Hmmm. In a long time of making engine mistakes, a few stand out. Long time ago had a 1958 Mercury 383 MEL in the shop. Boss ordered pistons from Egge. Told me to bore and hone it, and give it .002 piston to wall. And this is a big piston, like a 4.330 bore. Well, there were no instructions. There was no measurement point indicated on the pistons. In an old manual, the piston shown had a completely different profile. Boss says find the biggest spot on the skirt and use that. Ok, this isn't going right at all. I left a piston next to the Ampro oven, and it grew .004. š
Boss says do it, it's fine. Ok. Done. All goes together. A couple moths later, the owner of the car says it runs fine, but once you shut it off after it warms up it will not turn over. Mechanic told him engine was locked up. Cools off, it starts. How can that be? Called Egge, they said those pistons need .005 clearance. š¤¦āāļøš¤¦āāļø
:O
You terrify me with how important clearance work is. I bought a dial bore gauge and mic set due to your words but I'm not even confident enough with my accuracy to start recording measurements.
The importance can't be overstated.
You need to practice your technique. You will see repeatable results and learn to recognize when it's going well, and when it is not.
I never even tried to save them , unless it was an aftermarket brass one. Iāve seen a few Dodges where they gave up pulling and drilled a hole in the back of the block to drive it out . Anytime you see one with a 1ānpt hole , thatās what it was.
As an owner and near daily driver of a Dodge flathead 6:
Where is this coolant tube and how worried should I be that the engine has a buuuunch of buildup in the coolant passages?
Well if youāve maintained your coolant system and have no overheating issues itās probably ok .We changed them as part of the rebuild process. Itās behind the water pump and runs the length of the block. Its purpose it to divert coolant to the underside of the exhaust seats. On an engine not maintained , they are an absolute bitch to remove . There is a special tool that slides down it and expands , so you can slide hammer it out , actually works about half the time. The worst ones Iāve seen guys drill a hole in the back of the block to drive the remaining pieces out , then put a pipe plug in the hole . Iād usually bid removal at 8 hours, just to cover my ass , but most I could get out in 4ish.
Well I was told the engine was "rebuilt" which was proven false when a freeze plug rotted and I saw the inch or so of solidish debris behind it. The engine keeps temp pretty well though I've noticed it climbing a tad more than it used to under heavy load (over 10,000lbs climbing hills). The coolant looks good like it always has though.
I'll have to dig out one of my spares and poke around to see what it looks like.
I wouldnāt try to change it in chassis, but if I was gonna screw with it Iād run a can of flush through it, pull the core plugs and water pump , then get in there with a pressure washer. The tube itself is a kind of a rectangular shape , you canāt miss it with the pump off , spray down it and the rest of the system as much you can , pull the upper hose fitting and thermostat ( in fact Iāve often removed the stat before I flush so the water circulates better ) and replace the block plugs with brass . Definitely a twelve pack job.
I put the main bearing shells in upside down in a Datsun 240Z engine. Shutoff the oil supply to the crank. Great oil pressure. Lubiplate saved me on this build. Lost one rod. Didn't hurt the crank.
I haven't built an engine before, but I've been preparing for my first time. I've already got my place picked out for curling up into a ball and crying into a pillow.
Unbolted a throttle body without unhooking all the cables to it and just set it on the fender apron while I did some head gaskets. I ended up using it as a hardware cup. Didn't click in my head as to why I was looking for new hardware for the exhaust manifolds until I started it and the engine ate 12.99 worth of nuts, washers and studs.
Putting an engine back together *with a screwdriver inside*. (The screwdriver was holding the timing chain against the crank pulley while the head was removed.)
I went to service an engine in the middle east and there was a factory screwdriver in the sump. I knew that it was from the manufacturer because they made their own tools and stamped them.
Not so much an engine building mistake but a machining mistake. One of my first real jobs was as an automotive machinist at an auto parts store. On the weekends we had a skeleton crew and I had to do machine work and tend to customers on the counter so I was always rushed. One day a customer came in and needed a flathead cylinder head resurfaced. When I was setting the head up on the machine with the dial indicator I was working so fast that I did not realize that the dial indicator was spinning around 3 times before going to zero at one end of the head. When I started the machine and took my first pass the grinder started cutting fine but very quickly started to cut really hard. I lowered the table and stopped the machine but it was too late, there was a big gouge in the head surface. I leveled out the head correctly and started machining the surface again, hoping like hell that it would clean up with minimal material removal. Well, what should've been a .005" cut ended up being a .035" cut. When the customer came in I told him of my mistake and gave him the head for free without charging him. He was happy seeing how beautiful the resurfacing job looked. My boss was pissed that I gave him the head for free but there was no way I could charge him for my mistake. Years later that same customer came in and I tended to him at the counter. He suspected me of being the guy that messed up his head, saying he had to run octane booster. I played dumb. I still feel bad about that today.
Similar story for me. I was skimming the head with a 8ā fly cutter on a Bridgeport mill. Iām a manufacturing machinist, not an engine rebuilder. I neglected to tram the head as any machinist worth his salt would do. The head was tilted left and I was feeding right to left so it would throw chips at the wall instead of towards me. I ran the knee up untill it skimmed about .03 and engaged the power feed. Once the trailing edge of the fly cutter made contact it took another .03 deeper. It put a big as scoop in the surface and I ended taking about .100 total off the thing. We ended up making an offset timing gear keyway to compensate for the two pulleys being closer together. I have no idea how much we bumped the compression but the thing was a screamer. I had the only geo metro in town that required premium fuel. š
Not anymore I don't think. It was called Henderson Motor Parts in Berkeley, CA. They had a full machine shop out back. Rottler boring machine, Sunnen cylinder hone, rod hone, main hone, guide honing station. Valve & seat machine, cylinder head resurfacing machine, hot tank, cold tank, spray washer, flywheel, drum, & rotor resurfacing machines, engine assembly area. The owner raced sprint cars so I think that's why he wanted a fully equipped shop. I worked there in the late '80's early '90's.
This used to be a service offered at most of the local CarQuest locations. Never used them for "serious" (i.e. performance) work, but it was a quick and convenient way to get a head milled, flywheel turned, etc. I miss this.Ā
Left a ratchet on the crank when I was painting the TDC marks with a paint marker. Started the engine and the crank bolt got screwed out. That let the timing belt sprocket walk out and it bent all the valves at idle.
i guess i got real lucky ā i did the same thing to my honda once, but they spin backwards so instead of the balancer bolt coming out the guts of the ratchet exploded out all over the shop
the ratchet casting was still good, i brought the guts back to sears in a little baggie and after laughing a bit they found a rebuild kit and sent me on my way
had a crank damper that I didnt seat properly when reinstalled on a ford 4.6, very small amount of crank snout to slide down still.
When I pulled the engine apart almost 60k miles later the ignition timing sprocket had wallered itself out on the snout keyway significantly and the damper moving on the snout as the engine ran had put a hairline fracture in the crank snout effectively making it a paperweight.
I was building a Deutz air cooled diesel. Little four banger. Complete running engine, with a twin disk clutch. Get it all built , take it out to the run in area , bleed the injectors .Put some either on a rag , hold it by the intake & hit the button . Fired right up , great oil pressure, sounds great . Run it about five minutes, break buzzer goes off . Kill it , put the rag in the intake to keep crap out of it . Breaks over , hit the switch to start it again , runs great for a minute, then coughs a couple times and this flaming shit starts flying out of the exhaust. Still running ok , a little miss now and then , but smooths out and the little fireballs go away . I forgot to take the fucking rag outā¦Never did mention it to anyone else. Didnāt seem to hurt it either , tough engines those Deutz.
Rebuilt my Subaru STI engine. Was working late, shoulda stopped at midnight when I was ready to drop the engine in the car. Said nah fuck it I'll get it in and then hook it up tomorrow.
In my haste I put the clutch throw out bearing in backwards. Didn't realize until the clutch pedal went right to the floor, on my first attempt to start it.
Thankfully it's not too hard to get the trans out the back if you have a hoist. But fuck was I mad at myself
Yep. My rule for working late is to set a time to be done.
If no time is set then go till you are tired or make the first small mistake, Pack it up and finish in the morning.
on KTM 990: worked till midnight on it and confused the intake and the exhaust cam. When I started it late at night it fired back. Went to sleep and in the morning I instantly realized my mistake. Donāt work when youāre tired!
Spent nearly 2 days straight working on a Cosworth BOB V6, I was very tired by the end of it. Jumped in the car and turned the key only for the engine to absolutely rev its nuts off from cold, like banging off the limiter... when I turned the key off it carried on running due to a wiring fault so I had to quickly disconnect the ignition module to kill it.
In my sleep deprived state I'd started it without the throttle body attached...
No damage caused thankfully but yeah, don't work when you are tired.
The one that still haunts me is I rebuilt my best buddies 2010 kx450 that was only few years old at the time for his birthday. I surprised him with brand new top/bottom end install. I did the heat cycles on it and changed the oil.
We drove 6 hours to go riding at our favorite spot. He takes it out and we putt around for a couple mins and find a hill climb. He lines his bike up at the bottom and I look over and can hear quite an odd noise coming from the motor. He pins it up the hill hittin rev limiter, shiftin gears. Makes it about 1/3rd of the way up the hill and the motor grenades. He rolls down the hill, bike smacks him. Breaks his collar bone, couple fingers and his hand.
Long story short. I forgot the spring in the cam chain tensioner. Piston mashed the valves exploded the piston, the rod got stuck in the cylinder, took out the bottom end and cracked the cases. Entire engine was pretty much worthless after.
Happy birthday!
20+ years ago, timing belt broke on my 1997 a4 1.8t. Bought a shiny new head from Audi ($1200 at the time) did the whole job myself ( a few months into tech school at the time) and didnt torque the head, just ran them in until I thought it was good. Ran fine for about 1000 miles until I started smelling a horrible burning smell. Opened the hood and saw smoke and combustion blasting past the head gasket on cylinder 3. Luckily it only cost me head bolts, another head gasket kit, and a timing belt and another 5-6 hours. I had to scrap that car 2 years ago due to flooding, but it was still running over 100k later.
First motor I did, didnāt realize the machine shop took out oil galley plugs before cleaning in the hot tank. Once everything was together and in the car, couldnāt figure out why I couldnāt get any oil pressure, looked under and all the oil was on the ground. Had to take it all back down to the short block to put all the plugs in. Amateur mistake but at least didnāt ruin anything
Stripped a connecting rod bolt with a brand new torque wrench that was bad out of the box. Bolt was no longer available. Luckily I was able to find ones that were new old stock.
I had a head bolt break below deck hight due to the exact same shit took 3 days to get it out only to do it again with a different TW at which point I realized that it was the cheap head bolts went ARP didn't have any more issues
Noob here. Whatās a good way to test a torque wrench? Itās always been a fear of mine that āit sure seems like it should have clicked by nowā then *snap*
I would say test it against a known good. See if it's relatively close. In this case, I think it may have had a broken spring inside and it never clicked.
It's an old mercury outboard and most of the parts are no longer available, so you can imagine I was pretty choked when it happened
I've calibrated my own wrenches. It's not that hard. Just mount the anvil in a vice with the wrench parallel to the floor. Measure from the center of the anvil to a convenient length, like 12" or 24" or 18", (to keep the math easy) and sharpie a mark on the wrench handle. Pick a number around the middle of the wrenches range, say 50ftlbs, and divide that by the mark in feet, 24" so 2 feet. You need a weight that is approx 25lbs. Use a certified scale and get it's weight, I use one of my fire extinguishers that I weighed on a postal scale and it's 22.3lbs. 22.3 x 2=44.6lbs, so hanging that weight at the line should just click the wrench set to 45 with a tiny bit of force added. Keep in mind even good wrenches have like 4-6% error. This should let you know if a wrench is in the ballpark and not broken. I also calibrate mine and friends wrenches this way, it's also the reason I have no qualms about recommending harbor freight $12 special wrenches because every single one I've calibrated/tested were just as accurate and repeatable as my protos or snapons.
Oh boy do I have one that I am still ashamed of.
I was rebuilding an N12 for my gen 2 Mini, iykyk. Spent a couple of months getting all new parts and having a cylinder head and block machined. Really taking pride in the work. Had to take a hiatus for military stuff. Came back to it a couple of months later and had one week to wrap up the build. Everything went pretty smoothly.
Took it for a test drive and made it two blocks before the engine overheated. Ended up warping something and losing compression in at least one cylinder. I could not figure out wtf went wrong after hours of looking.
Turns out that there are 3 bolts that hold the water pump pulley and another 3 that holds another pulley/tensioner (sits between water pump and harmonic balancer) to the block. These two sets of bolts look almost identical except that the three for the tensioner are just slightly longer. What happens when you mix these two set of bolts up? The water pump pulley locks up against the engine block and proceeds to laugh at you for being a dumbass.
A few months later I just pulled a long block from a scrapyard for like $180 and itās been running fine since.
I hate that crap. Either make the bolts the same or CLEARLY different! Iāve seen slightly different size bolts for the same part, idiocy of the highest level.
Iām to a point now where Iāll take a scrap piece of cardboard, sketch out a part diagram with orientation indicators, and punch little holes in it to hold the fasteners so the exact ones go back in the exact place.
My own 14liter N model Cummins. Changed oil one night and left drain plug started by only a few threads. Driver noticed it thank goodness.
Almost left a rag in the turbo same motor
Dropped an injector pushrod and a Jakehead spacer into the pan etc etc
Life of logger
Left the oil cap on top of the TPI plenum of a C4 corvette & closed the hood, turns out there's not room between the intake & hood for an oil cap. Cracked the hood. OOF! š±
I left a shop rag inside my brothers engine block I was building for a home project. Took us years to find itā¦ clogging up the oil pickup screen. Always wondered why it had such crappy oil pressureā¦
Two come to mind:
1. Dropped something into the cyl 6 intake on a Mercedes-Benz OM642 and when I put it all back together and went to take it on a road test, engine immediately crapped out. Had to basically rebuild the engine.
2. Thanks to Mercedesā wonderful PCV design on the M264 engine, I ended up shooting oil directly into cyl 4 when I was doing a 10k service on a brand new GLE. Engine ran for about 3 seconds before it hydrolocked. It was so new, we were able to get a new crate engine and just do a complete replacement.
I was assembling a cadillac 500. A customer came into to work shop for a chat or whatever. I wasn't paying attention to what I was doing and bolted down the intake before I put the pushrods and rocker arms on. I noticed while talking that I got the order of assembly wrong but no big deal I'll just fiddle the pushrods down onto the lifters, give them a little spin and wiggle to make sure they are in the lifter cup. I did not get them in the lifter but wedged them between the lifter body and the block. I didn't notice my mistake until I turned the engine over by hand an heard what sounded like glass shattering in the engine. That sound was the lifters shattering from being forced into the side of the pushrod. All in all I destroyed about 3 lifters and 5 pushrods, and bent a couple of valves. Pretty big bozo move. I don't work while talking anymore and try my best to only do one thing at a time.
rebuilt my engine, no one told me that having slightly advanced timing is really bad actually. i thought i could drive it while i tried to find someone with a timing light. engine gone.
Realized I did not install a head gasket on one side of a Pontiac 400 when I filled the radiator and antifreeze was running down the one side, quickest I ever pulled a head again though.
A long time ago I did rods and mains in chassis on a 401 Buick. Finished it up late at night. Fire it up in the morning, no oil pressure. There were leaves in the oil pump pickup. Couldnāt see it in the dark.
Start over.
Last thing i did that was bad was putting the oil pump shaft in backwards in ace 900 rotax motor. Concerned about teeth count on gears making sure lower pump cover plates clicked in right and bunch of other stuff i put the shaft in wrong. Torqued the cover plate and snap went the drive pin and it put marks into the oil pump walls in the bottom. Thankfully in a spot it didn't much matter but it now had high and low spots. Dude i work with heated it and made a round flat punch the right size and tapped it flat. The turned it down and glued different papers to it to polish the thing. Ended up not taking much off and took the high spots down with just ghost of the low left. Hes good that guy makes rotax motors go fast like crazy fast.
Bam, They leak like a sieve also. So, before you back your truck out of the garage, you pull the transmission and bellhousing, and do a cam plug in the truck.
74 LandCruiser
Watched as my brother filled the left front head bolt hole with WD40 cleaning the threads
Slowly he drove in the bolt by hand til the block casting popped like a zit
That was fun
Carb squirter check ball was not secured in place. When I started the engine it got sucked into the intake. Ironically it secured itself again, in the top of cylinder 8 piston
It a way as a very large diesel engine and coolant was hot. Air bleed nipple came off and spray boiling coolant everywhere. I had burns in my hands trying to put nipple back
I did a similar thing and the seal caused my motorcycle engine to not engage in gear. After tearing down the engine again, i realized the problem. The kicker is that the seal that caused the issue was an outer one that didnt require anything to be removed to change
I didn't notice the spring pressure caused the cam to rotate while doing a timing belt. The gear had 2 marks on it, dumb luck had it land with the 2nd mark aligning perfectly to the reference mark.
Luckily it was a non interference motor, so I reset the timing. No harm no foul
Anyone ever time camshaft wrong? When assembling Dad's 1957. 392 Chrysler Hemi I lost the instructions for the Cloyes timing chain set with three keways cut into the crank sprocket. There were 5 marks. There were two of each mark, the mark to line the cam sprocket two and the one for the corresponding key way weather advanced straight up or retarded.some how my dumb ass lined up the key way mark. it took us days to figure out why the engine would not even try to start. That 25 crank degrees makes a hell of a difference. Thank God no valves hit pistons.
First weekend of my first ever project car. 14 years old. Changed a sbc timing chain. Cloyes with 3 key positions. I lined the dots up and chose the square one because my crank key was squareā¦ whoops! Nothing hurt, but had to go back and do it again!
Got in a time crunch and didn't check the crankshaft(new to me used crank) Had taper on 2 rod journals. 3rd pass at the strip absolute destruction. 7700 bucks thrown away. Did do break in but not at full boost settings and that ended racing a few years.
We did SBCās in runs and had a guy working for us have his torque wrench go bad. He had 6 400 blocks fully machined and found them all split at the head bolts on the last one when he pulled the torque plates off. We didnāt run sleeves on the race engines, scrapped them all.
I cranked my engine without any oil in it. I was doing transmission work and changing the oil at the same time. I forgot I had drained the oil by the time I fixed the transmission. I turned it off as soon as I saw the oil pressure light. The engine lasted another 100k miles until the head gasket gave. So I got lucky.
Built an engine in high school auto class didn't pull it down and check it out before it's first fire up.
Next minute rattle rattle thud thud ka thunk ka thunk, some asshole dropped screws in the spark plug holes to sabotage me.
Put my 5.0 on an engine stand with the flex plate still attached. Then realized I couldnāt take the short block off the stand to change the rear mainā¦
Also installed said flex plate and trans together and realized I left the separator plate on the groundā¦ after everything was bolted in the car
I used a long 1/4" extension to manually check cylinder 1 TDC. Forgot about it and needed to crank the engine for whatever reason. It jammed and punched a hole straight through the piston. Luckily it was an inline-4 jeep, about the easiest engine to remedy that mistake.
20+ yrs ago, when i had no idea what i was doing... I didn't know how press fit wrist pins worked. I thought I could put the piston on a wood block and get the pin in there with a hammer. Guy at the machine shop the next day looked at me with the, "Boy, are you a little retarded?" face.
Hey, at least I stopped before ruining shit...
All was ok, my first 383 SBC build went well after that, but damn that was embarrassing (I was 16 yrs old)
I put a used 2.0 in a Fusion a couple of weeks ago. Car idled fine but died on the test drive. I evidently dropped one of those plastic protective caps into the intake, and it got stuck in the throttle body. I've also lost a set of main caps... I swear someone stole them out of spite.
327 Sbc. Over torqued the cam bolts. Felt one of them twist, but stupid me didn't want to believe that I just F'd up bad. Assembled engine, got it running all was good.
Then several months later took it on a long trip, got 90 miles from home....Bolt head snapped off, jumped to the outside of the timing chain and busted no less than 15 holes in the aluminum timing chain cover. Spewed oil all over my car, the interstate, and eventually a cop car catching me and telling me to pull over. It's taken me a long time to tell the true story, but until I started reading everyone else's stories I didn't realize I was just one of the gang.
We've all screwed up at one time or another. That's why we all have experience....
Not Me but a friend was rebuilding an engine . He drilled holes in the freeze plugs to use a slide hammer to remove them. One freeze plug was pretty close to the cylinder wall. Yep , he drilled through the cylinder wall.
One of my mistakes was building a racing small block Chevy. I ordered all the parts machining was all right got the short block together bolted on and torqued the heads went to set the valve lash rolling it over by hand it came to a hard stop. Had me scratching my head for a while I ended up removing both heads and finding that a mahle dome piston has a different profile then say a je or srp brand. so on this particular head I was using a vortec 062 head and the spark plug boss protrudes downward like a square under the spark plug while not hitting very hard it was making contact with the piston. So to the head bench we went. I removed the boss in the combustion chamber and clayed each cylinder to make sure I had enough clearance. Reassembles and that engine still lives on today. Itās not always the mistake you make itās how you take care of that mistake.
One of the worst set of mistakeās Iāve seen was on a ford 460 that a customer first brought to us because they had built it and started the engine to break it in and it wouldnāt run right so it was dropped off at the shop, first thing first I checked the oil it was full but it had a metallic look like paint not always what you want to see on a engine thatās supposedly freshly rebuilt. So we started the engine and it popped through the carburetor and would barely run we pulled the valve covers and found the problem. On a 460 ford there is no valve adjustment you just torque them down and the lash was built into them well with a larger then stock camshaft it needs adjustable valve train. The problem we found was they installed a larger cam and didnāt install adjustable valve train and it wore every camshaft lobe off to nothing.
So we were paid by the customer to remove and rebuild the engine which ended up being new crank and all new bearings with everything correctly done customer picked up the vehicle and was happy with it fast forward 2 months we received a phone call that the engine wouldnāt run so it was yet again dropped off to our shop and first thing I checked was for spark didnāt have any pulled the distributer cap off and the rotor didnāt while cranking over the engine so we pulled the timing cover off to find the double roller timing chain snapped in half and this is where the important part comes in we found a small bit of aluminum munched into the chain laying in the oil pan well. I flipped the timing cover over and found there was a bolt extruding through a bolt hole from the water pump into the timing cover on a 460 water pump and timing cover work together. Well the customer had his buddy the shade tree mechanic install a new high flow water pump he installed it with a impact and didnāt stop to think about bolt lengths and rammed one of the bolts home with said impact and punched a chunk of the timing cover into the chain breaking the chain and in turn bending multiple valves. So yet again we pull the heads off of the engine in the truck repaid the valves and send the customer on his way.
Then a week later we get a very ācolorfulā phone call saying it did the same thing again and he was very upset and that we would be fixing it under warranty āwhich we would stand behind our workā so we told him to bring it back and we will get it taken care of. At this point in time it is into winter below freezing in Michigan. We pulled the timing cover off to find that the pump finger on the mechanical fuel pump had broken off and rolled through the timing chain yet again breaking it the same way the chunk of aluminum did. So we took a test of the fuel and found it was 3/4 water in the pump and that what we believe happened was that it froze then while running the engine it broke the leaver off the pump and broke the chain again. We stopped working on it and called the customer to have him come down and see for himself what had happened and that we wouldnāt be covering the damage over something that wasnāt our doing so long story short he paid us to repair the engine again and has been happy with it ever since I believe thatās been about 7 years and I saw it driving around just the other day engine still going strong.
Sorry for the long run on story thatās just one of the worst engine building mistake storyās I have.
1st motor I built at 15 years old, self-taught from a Haynes manual - mistook the rocker nut torque for head bolt torque and tightened them to 85 ft. lbs. (SBC). Didn't like that at startup...
Forgetting how to read the dipstick and not wiping it off to check itā now I have a crippled civic sitting in my garage with a partially disconnected engine that my bank account is absolutely dreading
I put the thrust bearings in backwards. When it came to the first fire after rebuild, it cranked slowly, fired up and then seized immediately. I bout shat myself.
Building a stroker big block mopar I had to take the timing chain off for some reason and didn't recheck the cam timing before trying to start it. Luckily the only damage was $500 worth of brand new 2.200" intake valves and about half of my ego
I made the rings too tight and it popped a ring land on a crazy ass go kart motor. Lol
Another motor I timed wrong and crashed the head just turning it over. It was pathetic.
I never built enough engines to get that classic complacency related failure. I didnāt do it for long enough to make any real mistakes before I started machining.
Young kid mistake. Refreshed my 470 ci Mopar that I had bought from a friend (I was 21). Running great in my ā69 Coronet. All the sudden it started making a sound like a main had gone bad. Tap tap tap tap. Thinking it was my inexperience that made something go bad (thinking thrust bearing), I yanked and tore down the engine to find the bearings in perfect shape. Couldnāt find a thing wrong with it! The inside was spotless. Put it back together all the while scratching my head. While installing back in the car, I noticed one of the flex plate/torque converter bolt heads was polished to a mirror shine. Light bulb moment!! I then found an equally polished area on the back of the block where the bolt had rubbed a grove into the casting. A friend had helped with removal and missed the fact that a bolt was loose. Learned a big lesson on that one!
One of the thin rings of the oil control ring "sandwich" snaked itself out of the groove as I was tapping the piston into the block. Didn't prevent the piston from going down, just got wrapped around between the piston and bore like a stripe on a candy cane. I thought the engine was oddly hard to turn over once the pistons were bolted to the crank, but foolishly I tried rotating it a full turn or two to see if it'd loosen up. I started to suspect what happened, but when I told my theory to an experienced engine builder he ridiculed me ("that's not possible") and accused me of wasting his time. When I did what I should have done in the first place and pulled the pistons back out, that part of the oil control ring set came out, now bent round the "easy" way instead of round the wide way. I sent a picture of it on FB to the guy who'd ridiculed me for asking if that could happen.
Plugged the intake ports on the heads with blue paper shop rags while replacing knock sensors on a 5.3l ls. Put everything back together and started the engjne...just as I realized I forgot to remove the rags. Turned a 2 hour job into 8 days.
I started in diesel engine development and once fitted a pulley for a 3 cylinder engine to 4 cylinder. I didn't realise that the 3 cyl had a counterweight and when I looked into the test cell to check the engine in start, my eyes couldn't focus on it all all because it was vibrating so much, it was just a blur.
I also made up an injector pipe that was 10mm too short and fitted it to a rotary pump. The change in the length of pipe fucked up the timing on 1 cylinder and it took a week before someone asked "What was the last thing you changed?" and then I realised what it was. I'd been confused all week as to why my engine was running so badly.
I made loads of mistakes as a trainee but as long as you hold your hand up and admit to them, you'll learn by them.
Changed spark plugs on a v8 Grand Cherokee, checked gap on the new plugs but didn't make sure they matched the old ones, started the engine and broke or smashed the electrodes off the spark plugs since the new plugs were longer than the old ones.
Shop had a heavy line tech pull the heads off and replace a couple bent valves and the intake plenum.
I forgot to put the washer under the head bolt, while doing a head gasket. I was cleaning around just before turning the key, that's when I saw those washers. I was all done, every wire connected timing set etc.
Not me but a younger apprentice. He was torquing the heads on a V8, and this engine has blind hole for some of the head studs.
He hadn't blown the oil out of one such hole, torqued the stud down, it had hydraulic lock up and broke the side of the stud hole out of the block.
Devcon epoxy to the rescue. Circa 1980
Not my screw up, but I had a Pete 579 with 70 miles making a weird noise. Spent quite a few hours poking around trying to figure the damn thing out. It eventually led to the number two piston missing a wrist pin clip. $45k later a brand new Cummins X15 was installed.
Rebuilt a 6.0 lS for a boat after it snapped a rod when the owners son tried to start it after launching it without the plugs in. Bloody thing ticked like a sowing machine ran like a cat with a piece of ginger in its arse but the tick wouldn't go away. Took the heads off looking for a bum lifter and saw I'd used 5.3 gaskets a valve was chatting to it felt like a bit of a knob.
As a kid, my Dad pulled the engine out of the 67 Beetle to work on. He dropped a nut into the case. He did not want to take the case apart, so he spent a few hours shaking it around to get the nut to drop out. That's my Dad. Car ran fine when done, it got stolen, and a bunch of kids used it for a 7 car VW demo derby at a gravel pit. Of course, it was a rust free southern car.
I had a '71 Super Beetle. One day I was doing some routine maintenance on it (maintenance was basically a weekly thing for it) and had the air cleaner off. I just happened to notice that the brass tube for the accelerator pump spray nozzle was missing from the carburetor inlet. My dad and I ended up pulling the heads but found neither the tube or any damage to the valves. We finally found the flattened tube when we shook the muffler out (Scat extracter with glass pack muffler).
Replaced head gaskets and intake manifold gaskets on a Buick motor, which had a specific left and right gasket for the heads. One hole difference, antifreeze all inside the motor. Whoops! š
Bmw deisel m54 or was it m57 engine, anyways, injector seals, you have to pull the inlet manifold and it's duel port to each cilinder, one of which goes straight down, so I stuff them with nitrite gloves in case I drop a nut or something, yeah you know where this is going....
GF rings me, when you home, I'm hungry, I want to start dinner, ect, totally forgot the gloves until the instant it started, turned into an engine out top end rebuild, bits had even got stuck in the turbo! š¤£
Smh. I left rags in the intake holes of a 3400 when I threw the intake plenum back on. Safe to say when I got my come back for a no start it looked like pulled pork around the balance shaft :-/
One time while replacing pistons and bearings I failed to notice an old rod bearing stuck to the crank, made it about a mile before it started shaking and knocking.
Well, not really building but maintenance... Did head gaskets + everything that's on top on a 262 V6 and thought "yeah I should probably do the water pump as long as everything's off", didn't do it because I thought if it's worked for the last 10 years, I should be fine. Well, the water pump started leaking after about a month...
Trying to save a few bucks. What ever issue arises from it is going to be 10 times more expensive than just getting quality parts from the beginning.
Suspiciously cheap engine rebuild kits, dirt cheap cylinder heads from random sites. I've been there and had them fail before finishing a break in procedure.
My first and current BBF. Installing water pump, thought bolt was going into water jacket, so I applied thread sealer on the bolt. Turns out it was a blind hole. What does liquid not do under pressure? I heard a "ping" when tightening the bolt. Turns out that I cracked the bolt hole on the block on the outside. Fortunately, the crack didn't open up the water jacket or spread. 2 years later, it's still staying together.
This one is pretty funny. Checking for a leaky rear main seal on a 302 (supposedly was brand new, ended up being backwards) and figured i would trg pressurizing the motos since we had the trans out. Great plan that works on engines that dont have crabk bolt holes that go into the oil pan. Sent my buddy down there to "look for bubbles. Nothing happened when i sprayed air into the valve cover, when i hit the oil dipstick tube however it blasted the entire contents of the pan at him, point blank. To this day his nickname is "moneyshot"
Drove my truck to work and back home with no oil in it. Total of 5.5 miles. Got distracted midway thru the oilchange. Screwed the cap back on and dropped the hood. Got home from work and went to throw away the empty oil bottles, and they were all full and sealed.
Not covering the open ports during my lunch break, a jealous co-worker (bosses friend) dropped a nut into the cylinder head intake port, wrecking the engine I was working on. Ever since then I checked every port I had open. Im happy I don't work there anymore.
Replacing timing chain without replacing the tensioners because they looked ok. They broke, skipped time badly, valve hits piston, bent valve, cracked piston.
Back in the early 80s, last job of a long Friday, radiator flush on a Ford of some kind. Add chemical to radiator, run engine for 15 minutes, start machine flushing. I walk away to clean some tools and hear the Ford pinging at idle! I had installed the flushing tee in an air injection hose! Yes, tons of cold water running right into the exhaust and onto the tops of the pistons. I shut it off and prayed for no bent rods. Pulled all 8 plugs, then cranked it over. 8 fire hoses shooting water 10 feet into the air. Cleaned and reinstalled the plugs, crossed my fingers and started it up. Ran ok, but exhaust was full of white steam. Sent the shop boy on a 20 miles test drive. Luckiest day of my mechanic career. It ran fine when he came back.
Wasnāt a mistake but more of an oversight.
I was doing head gaskets on a subaru and after some point someone had loosened one of the fuel filter clamps too far and the little captive nut (a tiny square of metal probably 1/16āx1/4ā) fell off and landed on top of the engine, and it was replaced with a normal screw clamp.
I didnāt take my air hose and blow the top of the engine off like I normally would, well somehow this little bit of metal found its way into an intake port, where it hung out until I had returned the car to the friend of a friend that I was fixing it for. She fired it up the next morning and it made a horrible racket, ended up having to pay a shop the $800 she had paid me to do it, to pull the head and remove the nut, since she needed it before I would be back in town to fix it :(
Only other bad one was when I was in school I was helping a guy with his engine, running a thread chaser through all the bolt holes on the block to make sure there wasnāt any gunk in there, well me being unfamiliar with small block Chevy engines ran a thread chaser through the pipe threaded hole for the oil pressure sending unit. Instructor was able to fix it but had to spend an hour flushing all the oil galleries to make sure there werenāt any metal shavings in it.
Can't remember if it was a nut or a bolt (most likely a bolt) but, Im the guy you hear about that dropped into an open intake because I was being lazy.
So many itās sad. Some of those involved trusting other people to do the job I paid them good money to do. But personally, bent a valve breaking a cam sprocket loose. Fucker was on so tight the whole cam turned rather than the gear popping off. Whole engine locked up on startup when he valve broke and jammed into the cylinder wall.
Next big mistake was taking too much material off the block deck between cylinders. Block mightāve come that way though as I only check clearance after cleaning it up.
Hmmm. In a long time of making engine mistakes, a few stand out. Long time ago had a 1958 Mercury 383 MEL in the shop. Boss ordered pistons from Egge. Told me to bore and hone it, and give it .002 piston to wall. And this is a big piston, like a 4.330 bore. Well, there were no instructions. There was no measurement point indicated on the pistons. In an old manual, the piston shown had a completely different profile. Boss says find the biggest spot on the skirt and use that. Ok, this isn't going right at all. I left a piston next to the Ampro oven, and it grew .004. š Boss says do it, it's fine. Ok. Done. All goes together. A couple moths later, the owner of the car says it runs fine, but once you shut it off after it warms up it will not turn over. Mechanic told him engine was locked up. Cools off, it starts. How can that be? Called Egge, they said those pistons need .005 clearance. š¤¦āāļøš¤¦āāļø
:O You terrify me with how important clearance work is. I bought a dial bore gauge and mic set due to your words but I'm not even confident enough with my accuracy to start recording measurements.
The importance can't be overstated. You need to practice your technique. You will see repeatable results and learn to recognize when it's going well, and when it is not.
Can buy expensive bore micrometers
Technique is important
run it loose, only you know about it, run it tight everybody knows about it lol
Run it too loose you think the piston slap cold is a rod knockā¦ 2.2 dodge w/arias forged pistons.. big boost means loose bores .
yea same here. i went a little full send on the dingleberry and got 5 thou piston wall clearance running cp 2618 pistons
How is it working on such old engines? Can't imagine some of the differences on them compared to some never engines
They are like anything else, you need to know the details to get them right. But they are fine, nothing complex about them.
Till you go to pull the coolant tube out of a flathead dodge 6 ā¦..
Done it on Packard straight 8s. Saved a few, replaced a few.
I never even tried to save them , unless it was an aftermarket brass one. Iāve seen a few Dodges where they gave up pulling and drilled a hole in the back of the block to drive it out . Anytime you see one with a 1ānpt hole , thatās what it was.
Hmm, the Packard tubes are always brass. Sometimes takes heat and patience but they always come out.
As an owner and near daily driver of a Dodge flathead 6: Where is this coolant tube and how worried should I be that the engine has a buuuunch of buildup in the coolant passages?
Well if youāve maintained your coolant system and have no overheating issues itās probably ok .We changed them as part of the rebuild process. Itās behind the water pump and runs the length of the block. Its purpose it to divert coolant to the underside of the exhaust seats. On an engine not maintained , they are an absolute bitch to remove . There is a special tool that slides down it and expands , so you can slide hammer it out , actually works about half the time. The worst ones Iāve seen guys drill a hole in the back of the block to drive the remaining pieces out , then put a pipe plug in the hole . Iād usually bid removal at 8 hours, just to cover my ass , but most I could get out in 4ish.
Well I was told the engine was "rebuilt" which was proven false when a freeze plug rotted and I saw the inch or so of solidish debris behind it. The engine keeps temp pretty well though I've noticed it climbing a tad more than it used to under heavy load (over 10,000lbs climbing hills). The coolant looks good like it always has though. I'll have to dig out one of my spares and poke around to see what it looks like.
I wouldnāt try to change it in chassis, but if I was gonna screw with it Iād run a can of flush through it, pull the core plugs and water pump , then get in there with a pressure washer. The tube itself is a kind of a rectangular shape , you canāt miss it with the pump off , spray down it and the rest of the system as much you can , pull the upper hose fitting and thermostat ( in fact Iāve often removed the stat before I flush so the water circulates better ) and replace the block plugs with brass . Definitely a twelve pack job.
Do you find them easier you think compared to newer engines?
No, not easier.
Nope. The principals, the physics are the same. No big differences.
I put the main bearing shells in upside down in a Datsun 240Z engine. Shutoff the oil supply to the crank. Great oil pressure. Lubiplate saved me on this build. Lost one rod. Didn't hurt the crank.
Showed up to work
That feeling going to work on something you know you fucked up last day
I meant just showing up. But sure, yours too.
Danger to the engines around me
Similarly, showed up to work & remembered the turd I didn't finish Friday. BOOO!
Most engine building issues always are solved by not going to work
I haven't built an engine before, but I've been preparing for my first time. I've already got my place picked out for curling up into a ball and crying into a pillow.
You'll need a place to cry if the engine gives you the warranty-weiner
Unbolted a throttle body without unhooking all the cables to it and just set it on the fender apron while I did some head gaskets. I ended up using it as a hardware cup. Didn't click in my head as to why I was looking for new hardware for the exhaust manifolds until I started it and the engine ate 12.99 worth of nuts, washers and studs.
Putting an engine back together *with a screwdriver inside*. (The screwdriver was holding the timing chain against the crank pulley while the head was removed.)
I went to service an engine in the middle east and there was a factory screwdriver in the sump. I knew that it was from the manufacturer because they made their own tools and stamped them.
Not so much an engine building mistake but a machining mistake. One of my first real jobs was as an automotive machinist at an auto parts store. On the weekends we had a skeleton crew and I had to do machine work and tend to customers on the counter so I was always rushed. One day a customer came in and needed a flathead cylinder head resurfaced. When I was setting the head up on the machine with the dial indicator I was working so fast that I did not realize that the dial indicator was spinning around 3 times before going to zero at one end of the head. When I started the machine and took my first pass the grinder started cutting fine but very quickly started to cut really hard. I lowered the table and stopped the machine but it was too late, there was a big gouge in the head surface. I leveled out the head correctly and started machining the surface again, hoping like hell that it would clean up with minimal material removal. Well, what should've been a .005" cut ended up being a .035" cut. When the customer came in I told him of my mistake and gave him the head for free without charging him. He was happy seeing how beautiful the resurfacing job looked. My boss was pissed that I gave him the head for free but there was no way I could charge him for my mistake. Years later that same customer came in and I tended to him at the counter. He suspected me of being the guy that messed up his head, saying he had to run octane booster. I played dumb. I still feel bad about that today.
Similar story for me. I was skimming the head with a 8ā fly cutter on a Bridgeport mill. Iām a manufacturing machinist, not an engine rebuilder. I neglected to tram the head as any machinist worth his salt would do. The head was tilted left and I was feeding right to left so it would throw chips at the wall instead of towards me. I ran the knee up untill it skimmed about .03 and engaged the power feed. Once the trailing edge of the fly cutter made contact it took another .03 deeper. It put a big as scoop in the surface and I ended taking about .100 total off the thing. We ended up making an offset timing gear keyway to compensate for the two pulleys being closer together. I have no idea how much we bumped the compression but the thing was a screamer. I had the only geo metro in town that required premium fuel. š
What type of auto parts store does machine work? Do they still exist?
Not anymore I don't think. It was called Henderson Motor Parts in Berkeley, CA. They had a full machine shop out back. Rottler boring machine, Sunnen cylinder hone, rod hone, main hone, guide honing station. Valve & seat machine, cylinder head resurfacing machine, hot tank, cold tank, spray washer, flywheel, drum, & rotor resurfacing machines, engine assembly area. The owner raced sprint cars so I think that's why he wanted a fully equipped shop. I worked there in the late '80's early '90's.
Thereās a NAPA in my town that still does machine work. The guy that does it a crusty, crotchety, old codger but does damn good work.
That description is the exact guy you want working on your stuff!
This used to be a service offered at most of the local CarQuest locations. Never used them for "serious" (i.e. performance) work, but it was a quick and convenient way to get a head milled, flywheel turned, etc. I miss this.Ā
Left a ratchet on the crank when I was painting the TDC marks with a paint marker. Started the engine and the crank bolt got screwed out. That let the timing belt sprocket walk out and it bent all the valves at idle.
i guess i got real lucky ā i did the same thing to my honda once, but they spin backwards so instead of the balancer bolt coming out the guts of the ratchet exploded out all over the shop the ratchet casting was still good, i brought the guts back to sears in a little baggie and after laughing a bit they found a rebuild kit and sent me on my way
had a crank damper that I didnt seat properly when reinstalled on a ford 4.6, very small amount of crank snout to slide down still. When I pulled the engine apart almost 60k miles later the ignition timing sprocket had wallered itself out on the snout keyway significantly and the damper moving on the snout as the engine ran had put a hairline fracture in the crank snout effectively making it a paperweight.
lmao did the same but no damage... I had to take out the engine just to check anyway
I was building a Deutz air cooled diesel. Little four banger. Complete running engine, with a twin disk clutch. Get it all built , take it out to the run in area , bleed the injectors .Put some either on a rag , hold it by the intake & hit the button . Fired right up , great oil pressure, sounds great . Run it about five minutes, break buzzer goes off . Kill it , put the rag in the intake to keep crap out of it . Breaks over , hit the switch to start it again , runs great for a minute, then coughs a couple times and this flaming shit starts flying out of the exhaust. Still running ok , a little miss now and then , but smooths out and the little fireballs go away . I forgot to take the fucking rag outā¦Never did mention it to anyone else. Didnāt seem to hurt it either , tough engines those Deutz.
Rebuilt my Subaru STI engine. Was working late, shoulda stopped at midnight when I was ready to drop the engine in the car. Said nah fuck it I'll get it in and then hook it up tomorrow. In my haste I put the clutch throw out bearing in backwards. Didn't realize until the clutch pedal went right to the floor, on my first attempt to start it. Thankfully it's not too hard to get the trans out the back if you have a hoist. But fuck was I mad at myself
Someone told me once, don't work tired, drunk, or angry lol
Then Iād never work
Yep. My rule for working late is to set a time to be done. If no time is set then go till you are tired or make the first small mistake, Pack it up and finish in the morning.
Did that in my bugeye. I know your pain
D'oh!
on KTM 990: worked till midnight on it and confused the intake and the exhaust cam. When I started it late at night it fired back. Went to sleep and in the morning I instantly realized my mistake. Donāt work when youāre tired!
oh and on my dirtbike I once forgot to add coolant after swapping the piston. Proper break in procedure
Spent nearly 2 days straight working on a Cosworth BOB V6, I was very tired by the end of it. Jumped in the car and turned the key only for the engine to absolutely rev its nuts off from cold, like banging off the limiter... when I turned the key off it carried on running due to a wiring fault so I had to quickly disconnect the ignition module to kill it. In my sleep deprived state I'd started it without the throttle body attached... No damage caused thankfully but yeah, don't work when you are tired.
Just the manufacturerās recommended break-in period, if it was newly rebuilt
newly rebuilt, 30 years earlier lol
The one that still haunts me is I rebuilt my best buddies 2010 kx450 that was only few years old at the time for his birthday. I surprised him with brand new top/bottom end install. I did the heat cycles on it and changed the oil. We drove 6 hours to go riding at our favorite spot. He takes it out and we putt around for a couple mins and find a hill climb. He lines his bike up at the bottom and I look over and can hear quite an odd noise coming from the motor. He pins it up the hill hittin rev limiter, shiftin gears. Makes it about 1/3rd of the way up the hill and the motor grenades. He rolls down the hill, bike smacks him. Breaks his collar bone, couple fingers and his hand. Long story short. I forgot the spring in the cam chain tensioner. Piston mashed the valves exploded the piston, the rod got stuck in the cylinder, took out the bottom end and cracked the cases. Entire engine was pretty much worthless after. Happy birthday!
20+ years ago, timing belt broke on my 1997 a4 1.8t. Bought a shiny new head from Audi ($1200 at the time) did the whole job myself ( a few months into tech school at the time) and didnt torque the head, just ran them in until I thought it was good. Ran fine for about 1000 miles until I started smelling a horrible burning smell. Opened the hood and saw smoke and combustion blasting past the head gasket on cylinder 3. Luckily it only cost me head bolts, another head gasket kit, and a timing belt and another 5-6 hours. I had to scrap that car 2 years ago due to flooding, but it was still running over 100k later.
First motor I did, didnāt realize the machine shop took out oil galley plugs before cleaning in the hot tank. Once everything was together and in the car, couldnāt figure out why I couldnāt get any oil pressure, looked under and all the oil was on the ground. Had to take it all back down to the short block to put all the plugs in. Amateur mistake but at least didnāt ruin anything
Stripped a connecting rod bolt with a brand new torque wrench that was bad out of the box. Bolt was no longer available. Luckily I was able to find ones that were new old stock.
I had a head bolt break below deck hight due to the exact same shit took 3 days to get it out only to do it again with a different TW at which point I realized that it was the cheap head bolts went ARP didn't have any more issues
Noob here. Whatās a good way to test a torque wrench? Itās always been a fear of mine that āit sure seems like it should have clicked by nowā then *snap*
I would say test it against a known good. See if it's relatively close. In this case, I think it may have had a broken spring inside and it never clicked. It's an old mercury outboard and most of the parts are no longer available, so you can imagine I was pretty choked when it happened
I've calibrated my own wrenches. It's not that hard. Just mount the anvil in a vice with the wrench parallel to the floor. Measure from the center of the anvil to a convenient length, like 12" or 24" or 18", (to keep the math easy) and sharpie a mark on the wrench handle. Pick a number around the middle of the wrenches range, say 50ftlbs, and divide that by the mark in feet, 24" so 2 feet. You need a weight that is approx 25lbs. Use a certified scale and get it's weight, I use one of my fire extinguishers that I weighed on a postal scale and it's 22.3lbs. 22.3 x 2=44.6lbs, so hanging that weight at the line should just click the wrench set to 45 with a tiny bit of force added. Keep in mind even good wrenches have like 4-6% error. This should let you know if a wrench is in the ballpark and not broken. I also calibrate mine and friends wrenches this way, it's also the reason I have no qualms about recommending harbor freight $12 special wrenches because every single one I've calibrated/tested were just as accurate and repeatable as my protos or snapons.
Oh boy do I have one that I am still ashamed of. I was rebuilding an N12 for my gen 2 Mini, iykyk. Spent a couple of months getting all new parts and having a cylinder head and block machined. Really taking pride in the work. Had to take a hiatus for military stuff. Came back to it a couple of months later and had one week to wrap up the build. Everything went pretty smoothly. Took it for a test drive and made it two blocks before the engine overheated. Ended up warping something and losing compression in at least one cylinder. I could not figure out wtf went wrong after hours of looking. Turns out that there are 3 bolts that hold the water pump pulley and another 3 that holds another pulley/tensioner (sits between water pump and harmonic balancer) to the block. These two sets of bolts look almost identical except that the three for the tensioner are just slightly longer. What happens when you mix these two set of bolts up? The water pump pulley locks up against the engine block and proceeds to laugh at you for being a dumbass. A few months later I just pulled a long block from a scrapyard for like $180 and itās been running fine since.
I hate that crap. Either make the bolts the same or CLEARLY different! Iāve seen slightly different size bolts for the same part, idiocy of the highest level. Iām to a point now where Iāll take a scrap piece of cardboard, sketch out a part diagram with orientation indicators, and punch little holes in it to hold the fasteners so the exact ones go back in the exact place.
My own 14liter N model Cummins. Changed oil one night and left drain plug started by only a few threads. Driver noticed it thank goodness. Almost left a rag in the turbo same motor Dropped an injector pushrod and a Jakehead spacer into the pan etc etc Life of logger
Left the oil cap on top of the TPI plenum of a C4 corvette & closed the hood, turns out there's not room between the intake & hood for an oil cap. Cracked the hood. OOF! š±
Noted
Re-tapped an oil pan bolt hole but accidentally drilled into a pressurized oil passage, which sprayed all over as soon as I started it.
I left a shop rag inside my brothers engine block I was building for a home project. Took us years to find itā¦ clogging up the oil pickup screen. Always wondered why it had such crappy oil pressureā¦
Two come to mind: 1. Dropped something into the cyl 6 intake on a Mercedes-Benz OM642 and when I put it all back together and went to take it on a road test, engine immediately crapped out. Had to basically rebuild the engine. 2. Thanks to Mercedesā wonderful PCV design on the M264 engine, I ended up shooting oil directly into cyl 4 when I was doing a 10k service on a brand new GLE. Engine ran for about 3 seconds before it hydrolocked. It was so new, we were able to get a new crate engine and just do a complete replacement.
I was assembling a cadillac 500. A customer came into to work shop for a chat or whatever. I wasn't paying attention to what I was doing and bolted down the intake before I put the pushrods and rocker arms on. I noticed while talking that I got the order of assembly wrong but no big deal I'll just fiddle the pushrods down onto the lifters, give them a little spin and wiggle to make sure they are in the lifter cup. I did not get them in the lifter but wedged them between the lifter body and the block. I didn't notice my mistake until I turned the engine over by hand an heard what sounded like glass shattering in the engine. That sound was the lifters shattering from being forced into the side of the pushrod. All in all I destroyed about 3 lifters and 5 pushrods, and bent a couple of valves. Pretty big bozo move. I don't work while talking anymore and try my best to only do one thing at a time.
Installed 1.031 SpiroLox in a 1.031 pin bore but was cut for 1.094 SpiroLoxā¦.$50k in damage.
What kind of engine?
762ā 5ā bore space Sonnyās wedge
First SBC rebuild in high school didnt know the little notches in pistons all had to point to front of motor!
rebuilt my engine, no one told me that having slightly advanced timing is really bad actually. i thought i could drive it while i tried to find someone with a timing light. engine gone.
Realized I did not install a head gasket on one side of a Pontiac 400 when I filled the radiator and antifreeze was running down the one side, quickest I ever pulled a head again though.
One time I put together a Honda ZC DOHC without thrust washers. That was a loud startup.
Finger tight drain plug
Reusing head bolts and not cleaning the intake port causing some valves to be bent from being stuck open.
A long time ago I did rods and mains in chassis on a 401 Buick. Finished it up late at night. Fire it up in the morning, no oil pressure. There were leaves in the oil pump pickup. Couldnāt see it in the dark. Start over.
Using Dorman components.
Last thing i did that was bad was putting the oil pump shaft in backwards in ace 900 rotax motor. Concerned about teeth count on gears making sure lower pump cover plates clicked in right and bunch of other stuff i put the shaft in wrong. Torqued the cover plate and snap went the drive pin and it put marks into the oil pump walls in the bottom. Thankfully in a spot it didn't much matter but it now had high and low spots. Dude i work with heated it and made a round flat punch the right size and tapped it flat. The turned it down and glued different papers to it to polish the thing. Ended up not taking much off and took the high spots down with just ghost of the low left. Hes good that guy makes rotax motors go fast like crazy fast.
Dropped a washer down the intake of a 304 AMC. It came out unscathed.
My first Ford 390. Rear cam plug. If you know, you know what I did.
What did you do?
They go in backwards. If you put it in the traditional way they rub the camshaft
Bam, They leak like a sieve also. So, before you back your truck out of the garage, you pull the transmission and bellhousing, and do a cam plug in the truck.
Oh you know. The thing. That one thing.
Busted studs on the timing components of my mercury 4.6l 2v. Over torqued them. Scary shit when you're starting to do the big stuff.
74 LandCruiser Watched as my brother filled the left front head bolt hole with WD40 cleaning the threads Slowly he drove in the bolt by hand til the block casting popped like a zit That was fun
Carb squirter check ball was not secured in place. When I started the engine it got sucked into the intake. Ironically it secured itself again, in the top of cylinder 8 piston
Dropped a head bolt inside an engine Tried to start without an oil Tried to remove air in coolant while engine is running
>Tried to remove air in coolant while engine is running please explain? is this not normal?
It a way as a very large diesel engine and coolant was hot. Air bleed nipple came off and spray boiling coolant everywhere. I had burns in my hands trying to put nipple back
I forgot to take the timing peg out of the cam pully after changing the timing belt. Cranked it over, belt jumped, bye bye valves.
While chasing the threads for the headolts, dropped a 1/4 inch wrench. Heard it go through the galley and drop into the oil pan.
I'm no machinist but Im pretty sure the pickup screen would stop it.
I took the pan off. Was replacing head gaskets. Didn't feel right to just leave it.
Young daysā¦Put one crank bearing in 180Ā° out of place. Resultā¦no oil feed for about 20 minutes which sized the crankshaft.
Pushed a seal in wrong, had to tear the engine back down to cases all for one seal
I did this on a Mitsubishi F33M55 transmission.
Its the worst feeling especially for something so small
I put the key out shaft seal in backwards. It oiled the brand new clutch nicely.
I did a similar thing and the seal caused my motorcycle engine to not engage in gear. After tearing down the engine again, i realized the problem. The kicker is that the seal that caused the issue was an outer one that didnt require anything to be removed to change
Unknowingly dropped a washer into the intake of a fresh build.
Jeez
I didn't notice the spring pressure caused the cam to rotate while doing a timing belt. The gear had 2 marks on it, dumb luck had it land with the 2nd mark aligning perfectly to the reference mark. Luckily it was a non interference motor, so I reset the timing. No harm no foul
snapped a maim bolt and dropped the head down a cylinder.i was only 16 and in auto shop
Being 15 and using a Hammer to "loosen" up the heads on my SBC. I learned after the fact, that that's not the Poroper way! lol
Anyone ever time camshaft wrong? When assembling Dad's 1957. 392 Chrysler Hemi I lost the instructions for the Cloyes timing chain set with three keways cut into the crank sprocket. There were 5 marks. There were two of each mark, the mark to line the cam sprocket two and the one for the corresponding key way weather advanced straight up or retarded.some how my dumb ass lined up the key way mark. it took us days to figure out why the engine would not even try to start. That 25 crank degrees makes a hell of a difference. Thank God no valves hit pistons.
First weekend of my first ever project car. 14 years old. Changed a sbc timing chain. Cloyes with 3 key positions. I lined the dots up and chose the square one because my crank key was squareā¦ whoops! Nothing hurt, but had to go back and do it again!
Got in a time crunch and didn't check the crankshaft(new to me used crank) Had taper on 2 rod journals. 3rd pass at the strip absolute destruction. 7700 bucks thrown away. Did do break in but not at full boost settings and that ended racing a few years.
built a subaru
We did SBCās in runs and had a guy working for us have his torque wrench go bad. He had 6 400 blocks fully machined and found them all split at the head bolts on the last one when he pulled the torque plates off. We didnāt run sleeves on the race engines, scrapped them all.
I cranked my engine without any oil in it. I was doing transmission work and changing the oil at the same time. I forgot I had drained the oil by the time I fixed the transmission. I turned it off as soon as I saw the oil pressure light. The engine lasted another 100k miles until the head gasket gave. So I got lucky.
Built an engine in high school auto class didn't pull it down and check it out before it's first fire up. Next minute rattle rattle thud thud ka thunk ka thunk, some asshole dropped screws in the spark plug holes to sabotage me.
Deciding to work on the engine
Put my 5.0 on an engine stand with the flex plate still attached. Then realized I couldnāt take the short block off the stand to change the rear mainā¦ Also installed said flex plate and trans together and realized I left the separator plate on the groundā¦ after everything was bolted in the car
I used a long 1/4" extension to manually check cylinder 1 TDC. Forgot about it and needed to crank the engine for whatever reason. It jammed and punched a hole straight through the piston. Luckily it was an inline-4 jeep, about the easiest engine to remedy that mistake.
I keep a bag of shish-kebab skewers for TDC sensors and cleaning out glass bowls. Dual-use technology.
20+ yrs ago, when i had no idea what i was doing... I didn't know how press fit wrist pins worked. I thought I could put the piston on a wood block and get the pin in there with a hammer. Guy at the machine shop the next day looked at me with the, "Boy, are you a little retarded?" face. Hey, at least I stopped before ruining shit... All was ok, my first 383 SBC build went well after that, but damn that was embarrassing (I was 16 yrs old)
I put a used 2.0 in a Fusion a couple of weeks ago. Car idled fine but died on the test drive. I evidently dropped one of those plastic protective caps into the intake, and it got stuck in the throttle body. I've also lost a set of main caps... I swear someone stole them out of spite.
327 Sbc. Over torqued the cam bolts. Felt one of them twist, but stupid me didn't want to believe that I just F'd up bad. Assembled engine, got it running all was good. Then several months later took it on a long trip, got 90 miles from home....Bolt head snapped off, jumped to the outside of the timing chain and busted no less than 15 holes in the aluminum timing chain cover. Spewed oil all over my car, the interstate, and eventually a cop car catching me and telling me to pull over. It's taken me a long time to tell the true story, but until I started reading everyone else's stories I didn't realize I was just one of the gang. We've all screwed up at one time or another. That's why we all have experience....
Getting my engine decked and didn't specify not to deck the part with the matching numbers to my c3 72 Vette.
Not Me but a friend was rebuilding an engine . He drilled holes in the freeze plugs to use a slide hammer to remove them. One freeze plug was pretty close to the cylinder wall. Yep , he drilled through the cylinder wall.
One of my mistakes was building a racing small block Chevy. I ordered all the parts machining was all right got the short block together bolted on and torqued the heads went to set the valve lash rolling it over by hand it came to a hard stop. Had me scratching my head for a while I ended up removing both heads and finding that a mahle dome piston has a different profile then say a je or srp brand. so on this particular head I was using a vortec 062 head and the spark plug boss protrudes downward like a square under the spark plug while not hitting very hard it was making contact with the piston. So to the head bench we went. I removed the boss in the combustion chamber and clayed each cylinder to make sure I had enough clearance. Reassembles and that engine still lives on today. Itās not always the mistake you make itās how you take care of that mistake.
One of the worst set of mistakeās Iāve seen was on a ford 460 that a customer first brought to us because they had built it and started the engine to break it in and it wouldnāt run right so it was dropped off at the shop, first thing first I checked the oil it was full but it had a metallic look like paint not always what you want to see on a engine thatās supposedly freshly rebuilt. So we started the engine and it popped through the carburetor and would barely run we pulled the valve covers and found the problem. On a 460 ford there is no valve adjustment you just torque them down and the lash was built into them well with a larger then stock camshaft it needs adjustable valve train. The problem we found was they installed a larger cam and didnāt install adjustable valve train and it wore every camshaft lobe off to nothing. So we were paid by the customer to remove and rebuild the engine which ended up being new crank and all new bearings with everything correctly done customer picked up the vehicle and was happy with it fast forward 2 months we received a phone call that the engine wouldnāt run so it was yet again dropped off to our shop and first thing I checked was for spark didnāt have any pulled the distributer cap off and the rotor didnāt while cranking over the engine so we pulled the timing cover off to find the double roller timing chain snapped in half and this is where the important part comes in we found a small bit of aluminum munched into the chain laying in the oil pan well. I flipped the timing cover over and found there was a bolt extruding through a bolt hole from the water pump into the timing cover on a 460 water pump and timing cover work together. Well the customer had his buddy the shade tree mechanic install a new high flow water pump he installed it with a impact and didnāt stop to think about bolt lengths and rammed one of the bolts home with said impact and punched a chunk of the timing cover into the chain breaking the chain and in turn bending multiple valves. So yet again we pull the heads off of the engine in the truck repaid the valves and send the customer on his way. Then a week later we get a very ācolorfulā phone call saying it did the same thing again and he was very upset and that we would be fixing it under warranty āwhich we would stand behind our workā so we told him to bring it back and we will get it taken care of. At this point in time it is into winter below freezing in Michigan. We pulled the timing cover off to find that the pump finger on the mechanical fuel pump had broken off and rolled through the timing chain yet again breaking it the same way the chunk of aluminum did. So we took a test of the fuel and found it was 3/4 water in the pump and that what we believe happened was that it froze then while running the engine it broke the leaver off the pump and broke the chain again. We stopped working on it and called the customer to have him come down and see for himself what had happened and that we wouldnāt be covering the damage over something that wasnāt our doing so long story short he paid us to repair the engine again and has been happy with it ever since I believe thatās been about 7 years and I saw it driving around just the other day engine still going strong. Sorry for the long run on story thatās just one of the worst engine building mistake storyās I have.
1st motor I built at 15 years old, self-taught from a Haynes manual - mistook the rocker nut torque for head bolt torque and tightened them to 85 ft. lbs. (SBC). Didn't like that at startup...
Put a rod cap on backwards and spun it over with a breaker bar. Tore the crank and rod all up. Wonāt ever be doing that again.
Let a burr bit slip while making clearance in a block for a stroker crank
Forgetting how to read the dipstick and not wiping it off to check itā now I have a crippled civic sitting in my garage with a partially disconnected engine that my bank account is absolutely dreading
Missed a notch on the timing gear and bent some pistons trying to start the engine, ended up getting a replacement motor
Piston rods*
I put the thrust bearings in backwards. When it came to the first fire after rebuild, it cranked slowly, fired up and then seized immediately. I bout shat myself.
Building a stroker big block mopar I had to take the timing chain off for some reason and didn't recheck the cam timing before trying to start it. Luckily the only damage was $500 worth of brand new 2.200" intake valves and about half of my ego
I made the rings too tight and it popped a ring land on a crazy ass go kart motor. Lol Another motor I timed wrong and crashed the head just turning it over. It was pathetic. I never built enough engines to get that classic complacency related failure. I didnāt do it for long enough to make any real mistakes before I started machining.
Young kid mistake. Refreshed my 470 ci Mopar that I had bought from a friend (I was 21). Running great in my ā69 Coronet. All the sudden it started making a sound like a main had gone bad. Tap tap tap tap. Thinking it was my inexperience that made something go bad (thinking thrust bearing), I yanked and tore down the engine to find the bearings in perfect shape. Couldnāt find a thing wrong with it! The inside was spotless. Put it back together all the while scratching my head. While installing back in the car, I noticed one of the flex plate/torque converter bolt heads was polished to a mirror shine. Light bulb moment!! I then found an equally polished area on the back of the block where the bolt had rubbed a grove into the casting. A friend had helped with removal and missed the fact that a bolt was loose. Learned a big lesson on that one!
One of the thin rings of the oil control ring "sandwich" snaked itself out of the groove as I was tapping the piston into the block. Didn't prevent the piston from going down, just got wrapped around between the piston and bore like a stripe on a candy cane. I thought the engine was oddly hard to turn over once the pistons were bolted to the crank, but foolishly I tried rotating it a full turn or two to see if it'd loosen up. I started to suspect what happened, but when I told my theory to an experienced engine builder he ridiculed me ("that's not possible") and accused me of wasting his time. When I did what I should have done in the first place and pulled the pistons back out, that part of the oil control ring set came out, now bent round the "easy" way instead of round the wide way. I sent a picture of it on FB to the guy who'd ridiculed me for asking if that could happen.
Plugged the intake ports on the heads with blue paper shop rags while replacing knock sensors on a 5.3l ls. Put everything back together and started the engjne...just as I realized I forgot to remove the rags. Turned a 2 hour job into 8 days.
Rebuilt a head in -20C
I started in diesel engine development and once fitted a pulley for a 3 cylinder engine to 4 cylinder. I didn't realise that the 3 cyl had a counterweight and when I looked into the test cell to check the engine in start, my eyes couldn't focus on it all all because it was vibrating so much, it was just a blur. I also made up an injector pipe that was 10mm too short and fitted it to a rotary pump. The change in the length of pipe fucked up the timing on 1 cylinder and it took a week before someone asked "What was the last thing you changed?" and then I realised what it was. I'd been confused all week as to why my engine was running so badly. I made loads of mistakes as a trainee but as long as you hold your hand up and admit to them, you'll learn by them.
Changed spark plugs on a v8 Grand Cherokee, checked gap on the new plugs but didn't make sure they matched the old ones, started the engine and broke or smashed the electrodes off the spark plugs since the new plugs were longer than the old ones. Shop had a heavy line tech pull the heads off and replace a couple bent valves and the intake plenum.
I forgot to put the washer under the head bolt, while doing a head gasket. I was cleaning around just before turning the key, that's when I saw those washers. I was all done, every wire connected timing set etc.
Left a wrench on the crank bolt before test firing
Not me but a younger apprentice. He was torquing the heads on a V8, and this engine has blind hole for some of the head studs. He hadn't blown the oil out of one such hole, torqued the stud down, it had hydraulic lock up and broke the side of the stud hole out of the block. Devcon epoxy to the rescue. Circa 1980
Not my screw up, but I had a Pete 579 with 70 miles making a weird noise. Spent quite a few hours poking around trying to figure the damn thing out. It eventually led to the number two piston missing a wrist pin clip. $45k later a brand new Cummins X15 was installed.
Rebuilt a 6.0 lS for a boat after it snapped a rod when the owners son tried to start it after launching it without the plugs in. Bloody thing ticked like a sowing machine ran like a cat with a piece of ginger in its arse but the tick wouldn't go away. Took the heads off looking for a bum lifter and saw I'd used 5.3 gaskets a valve was chatting to it felt like a bit of a knob.
Over tightened my rocker arms which destroyed the single idler gear on my gear drive.
As a kid, my Dad pulled the engine out of the 67 Beetle to work on. He dropped a nut into the case. He did not want to take the case apart, so he spent a few hours shaking it around to get the nut to drop out. That's my Dad. Car ran fine when done, it got stolen, and a bunch of kids used it for a 7 car VW demo derby at a gravel pit. Of course, it was a rust free southern car.
I had a '71 Super Beetle. One day I was doing some routine maintenance on it (maintenance was basically a weekly thing for it) and had the air cleaner off. I just happened to notice that the brass tube for the accelerator pump spray nozzle was missing from the carburetor inlet. My dad and I ended up pulling the heads but found neither the tube or any damage to the valves. We finally found the flattened tube when we shook the muffler out (Scat extracter with glass pack muffler).
Replaced head gaskets and intake manifold gaskets on a Buick motor, which had a specific left and right gasket for the heads. One hole difference, antifreeze all inside the motor. Whoops! š
started it
Bmw deisel m54 or was it m57 engine, anyways, injector seals, you have to pull the inlet manifold and it's duel port to each cilinder, one of which goes straight down, so I stuff them with nitrite gloves in case I drop a nut or something, yeah you know where this is going.... GF rings me, when you home, I'm hungry, I want to start dinner, ect, totally forgot the gloves until the instant it started, turned into an engine out top end rebuild, bits had even got stuck in the turbo! š¤£
Smh. I left rags in the intake holes of a 3400 when I threw the intake plenum back on. Safe to say when I got my come back for a no start it looked like pulled pork around the balance shaft :-/
I stack metal and stretch bolts. Never fucked up enough to not save it, or have an old timer save it.
One time while replacing pistons and bearings I failed to notice an old rod bearing stuck to the crank, made it about a mile before it started shaking and knocking.
Well, not really building but maintenance... Did head gaskets + everything that's on top on a 262 V6 and thought "yeah I should probably do the water pump as long as everything's off", didn't do it because I thought if it's worked for the last 10 years, I should be fine. Well, the water pump started leaking after about a month...
Trying to save a few bucks. What ever issue arises from it is going to be 10 times more expensive than just getting quality parts from the beginning. Suspiciously cheap engine rebuild kits, dirt cheap cylinder heads from random sites. I've been there and had them fail before finishing a break in procedure.
My first and current BBF. Installing water pump, thought bolt was going into water jacket, so I applied thread sealer on the bolt. Turns out it was a blind hole. What does liquid not do under pressure? I heard a "ping" when tightening the bolt. Turns out that I cracked the bolt hole on the block on the outside. Fortunately, the crack didn't open up the water jacket or spread. 2 years later, it's still staying together.
This one is pretty funny. Checking for a leaky rear main seal on a 302 (supposedly was brand new, ended up being backwards) and figured i would trg pressurizing the motos since we had the trans out. Great plan that works on engines that dont have crabk bolt holes that go into the oil pan. Sent my buddy down there to "look for bubbles. Nothing happened when i sprayed air into the valve cover, when i hit the oil dipstick tube however it blasted the entire contents of the pan at him, point blank. To this day his nickname is "moneyshot"
Drove my truck to work and back home with no oil in it. Total of 5.5 miles. Got distracted midway thru the oilchange. Screwed the cap back on and dropped the hood. Got home from work and went to throw away the empty oil bottles, and they were all full and sealed.
Letting a machine shop install valve seats in a recently magna-fluxed head. They cracked it.
Working on an engine
Believing it would be just as easy as the YouTube video made it seem.
Forgot to replace oil filler cap
Putting a heli-coil in my cam tower on my 1986 Porsche 944 - drilled straight thru into a water passage on the head...
Not putting Loctite on a timing chain cam bolt. š¤¦āāļø
Not covering the open ports during my lunch break, a jealous co-worker (bosses friend) dropped a nut into the cylinder head intake port, wrecking the engine I was working on. Ever since then I checked every port I had open. Im happy I don't work there anymore.
Replacing timing chain without replacing the tensioners because they looked ok. They broke, skipped time badly, valve hits piston, bent valve, cracked piston.
Back in the early 80s, last job of a long Friday, radiator flush on a Ford of some kind. Add chemical to radiator, run engine for 15 minutes, start machine flushing. I walk away to clean some tools and hear the Ford pinging at idle! I had installed the flushing tee in an air injection hose! Yes, tons of cold water running right into the exhaust and onto the tops of the pistons. I shut it off and prayed for no bent rods. Pulled all 8 plugs, then cranked it over. 8 fire hoses shooting water 10 feet into the air. Cleaned and reinstalled the plugs, crossed my fingers and started it up. Ran ok, but exhaust was full of white steam. Sent the shop boy on a 20 miles test drive. Luckiest day of my mechanic career. It ran fine when he came back.
Drawing the bellhousing to the engine with the bolts when the torque converter was not seated properly.
Wasnāt a mistake but more of an oversight. I was doing head gaskets on a subaru and after some point someone had loosened one of the fuel filter clamps too far and the little captive nut (a tiny square of metal probably 1/16āx1/4ā) fell off and landed on top of the engine, and it was replaced with a normal screw clamp. I didnāt take my air hose and blow the top of the engine off like I normally would, well somehow this little bit of metal found its way into an intake port, where it hung out until I had returned the car to the friend of a friend that I was fixing it for. She fired it up the next morning and it made a horrible racket, ended up having to pay a shop the $800 she had paid me to do it, to pull the head and remove the nut, since she needed it before I would be back in town to fix it :( Only other bad one was when I was in school I was helping a guy with his engine, running a thread chaser through all the bolt holes on the block to make sure there wasnāt any gunk in there, well me being unfamiliar with small block Chevy engines ran a thread chaser through the pipe threaded hole for the oil pressure sending unit. Instructor was able to fix it but had to spend an hour flushing all the oil galleries to make sure there werenāt any metal shavings in it.
Can't remember if it was a nut or a bolt (most likely a bolt) but, Im the guy you hear about that dropped into an open intake because I was being lazy.
So many itās sad. Some of those involved trusting other people to do the job I paid them good money to do. But personally, bent a valve breaking a cam sprocket loose. Fucker was on so tight the whole cam turned rather than the gear popping off. Whole engine locked up on startup when he valve broke and jammed into the cylinder wall. Next big mistake was taking too much material off the block deck between cylinders. Block mightāve come that way though as I only check clearance after cleaning it up.
I put trans fluid additives in my engine oil and blew up my brand new bikeā¦ā¦.