engine building mistakes

hey guys im just curious as to what have been some of your most rookie mistakes building an engine, and if you decided to still run it!! ive done it, so i curious to see :D

If anyone actually admits their mistakes....

I've had problems with main seals.

The big one was a rebuild going into a 4x4 Bronco. Bolted it all up and fired it, yeah big oil leak. I was being paid flat rate at the time so that one killed me.

put on a timing cover in a 69 camaro that someone had removed with a screwdriver.. since it came off clean i didnt even give it a second look when bolting it back together.. u could see about 3/8 of an inch of daylight through that puppy where they pried it off.... big mess

Finding out my torque wrench was out of whack, and not checking for bolt stretch after I got the bottom end loosen up and re-torque(new wrench). Very expensive lesson.

Joel

not cleaning my crank after getting it turned!!! it was a steel crank and i (assumed) they clean it realy good... big mistake!! take the time and cleand all the oil holes it will save you big money!!

When I was 14 my father & I built a small block for a 55 chevy I had & we were following that book "how to rebuild your small block chevy" & we overlooked the oil pump drive shaft. It only ran for maybe 45 seconds but it was enough to ruin most of the bearings in the thing. I'm 34 now I still laugh everytime I see an oil pump drive shaft.

I've had a couple. One was when I put a set of intake gaskets on a cop car. I put the water block off plates to the front of the intake instead of the back. The gasket said this side up though but the plate where on the wrong end. I tested it out and drove it it was all fine until the cops come and got the car and while on patrol the bottom hose blows off. First job at a new dealership after tech school. :eek:

The other was forgot to torque the camshaft timing chain bolts. Person brought it back to me with a grinding noise in the front end of the motor. Those 3 bolts were backing out and left a perfect circle in the cover.

Lessons learned that I will not forget!!!!:yes:

Didn't break in a cam, just started it and messed around with timing a little then drove it. About four cam lobes were completley rounded after the first couple hundred miles.

Break those cams in properly or you'll pay.

The other was forgot to torque the camshaft timing chain bolts. Person brought it back to me with a grinding noise in the front end of the motor. Those 3 bolts were backing out and left a perfect circle in the cover.
Been there don that! Mine cost me a distributor cam and lifters because the cheap aftermarket cover let the cam come out way to far. I haven't put together an engine since without a lockplate on the cam bolts.
My other biggest mistake was I had an egine given to me. It had been rebuilt several years before and never started. It had been sitting uncovered in a shop that a 1,000,000 Mud Daubers called home. They got into the engine somehow and made nests. My dad refused to let me pull the engine apart and clean it out. We sprayed diesel into it to clean them out. The engine ran about 5 minutes before the oil turned brown and had grit in it. I drove it for a couple of weeks and the oil pressure dropped to near nothing. I pulled it apart the steel crank and bearing were shot. Alll it needed after that was a crank, bearings and hot tanked. :mad:

Yep, have a good one too. Back right after high school, I lost the engine in my 77 Firebird that I waas using as a daily driver. Well, since this was my only way to work (no busses ran out there) I needed to change the engine quickly. Well the first day I found a ride to work, worked over, came home, pulled the engine got the "new" one ready to drop in, showered, went back to work, came home and finished the engine swap (2nd night) all without sleep. I was exhausted and cranky to say the least. Well I got it done that second night and fired her up. I didn't change the cam, so no need for a break in. The engine ran for about 2 minutes before I noticed the knocking. I shut it down and tried to figure out what I had forgotten. Torque convertor bolts? Did I put a cracked flywhell on it? Broken pushrod? Bad cam/lifters? NOPE. Dumb*** me, in a hurry to get it running forgot one important thing. OIL! They don't last too long without it. The next day I bought a $600 1976 Olds Cutlass.

1.NOT Honing cyclenders re-using old rings
2.Over Torquing bottem-end
3.fixing 3.1 motor lower intake gaskits and forgot to reinstall the rockers/pushrods almost finished off assembly befor l realized
4.built a 400hp race-only engine made to last only a weekend guy purchased it from me and owndered why after putting it into his daily driver is started to squikity quirk from the comp-cam...............l sold it USED Race ONLY Track motor and yet somehow people can't understand that

don't know if it's a mistake, but the gear on my distributor was bad. causing the overheating and timing issue. spent money on a new fan (needed anyways), new gauges, etc. then found out it was the distributor gear. i bought a new msd distributor, fixed that problem :) yay

Newly built engine. Went through my long check list. Proceeded to break in the cam. Forgot to pull the two rubber plugs off my remote breather tubes. The pressure built up and popped the rear intake seal. Glad it didnt pop the main rear or front. Rushing to get it fired. I Didn't completely go through my check list. The "remove breather plugs" was written right on it.. DUH!!!!! JR

My first engine I had the timing chain off a tooth and the distributor out 180. On my second engine I checked and double checked the timing chain and still assembled it one tooth off. Now I triple check!

When I was 16 I rebuilt the 265 in my 55 chevy. I forgot to check the end gap on the rings and just slapped them on the pistons. Needless to say it broke most of the rings and it was blowing smoke like mad. My dad helped me take it apart and this time I did it right with his help..

A while back about 10-12 years ago) I did head gaskets on a toyota four runner V6, a very time consuming job. When I got done the thermostat would not open till the thing was really hot and would then shut again. Well come to find out there are two different head gaskets and I had them on the wrong side of the motor. Worked for free for a day and a half to fix that one. :mad:

How about not tightening one of the rod caps all of the way on a 350? That sure made a mess when part of the cap shot out through my oil pan shortly after I started it up.

I got very lax about the heads. Didn't torque them in 20lb steps, didn't much pay attention to tightening pettern. And I wasn't very gernerous with thread sealer. Cost me a head gasket replacement and a whole lot of labor (I pulled the motor). From now on, the heads are worshiped in my garage!

When rebuilding the 350 in my 69, I didn't adjust the valves properly. I replaced the cam and lifters, this was a hydraulic cam. After trying to start engine for 45 minutes and nothing. Loosened up all the valves and it started. Ran for 2 days before wiping several lobes off cam. Replaced cam and lifters, changed oil and filter. Thought everything was good to go. Nope engine only had 5 psi oil pressure at idle. Pulled engine back out, bearings were shot as well as crank journals. Had crank ground and replaced bearings. Learned an expensive lesson on that one. I would much rather have the valves set on the loose side and hear the lifters ticking than have them set too tight. Needless to say I learned how to adjust the valves.

You just reminded me of one mine also. Didn't know how to adjust lifter pre-load when I installed my first cam. Set them at overlap instead of at TDC or using a correct procedure. That motor turned over very easily and indicated something was terribly wrong.

A thread like is good because it shows we all learned things through mistakes. And if you aren't making mistakes you probably aren't doing anything or learning anything. :D

Well this happened to me about a year ago. I was helping my buddy get his motot fired up on the test stand. Our stand is just using the engine stand with some homemade supports so nothing moves. Ok I wired the plug wires the same way that I have done 100 times. Ok it's the moment we have been waiting for, for about 6 months start to turn it over you just know that it's bout to go VROOM. WRONG. What's the deal checked everything. Got current going to the distributor, Valves are adjusted correctly, and gas is pumping up. Try again. Nothing. What the He!! At this point I'm getting fustrated and just walking in circles. My buddy just about ready to EXPLODE all this time and money wasted. Well another guy came up to the shop we told him the problem. He stood thier for literally about 2 seconds and said the wires are going in the wrong direction! WHAT!!!!!!!! I checked and double checked that 10 times. Then it hits me (LMAO) I was standing behind it near the flywheel when I was wiring it up. Guess I was just use to doing it when its in the car.

Ok.....
I was rebuilding my 302 and worked the oil pump over per "How to Hotrod the small Chevy" Book. Grumpy trick!! I did all the measuring and putting groves in the plate and installed the pump. Fired the motor up and ...BOOM!! The oil filter blew!! :eek: 7 quarts of oil on the driveway!! Scratching my head...going thru the steps on what I did wrong. Cleaned the mess up and installed another filter thinking that it was defective. Fired it up and....Boom!!!!!!! Oil pressure went to 100 + and filter blew again!! :eek:

*** went wrong this time!! :turn: When I did the pump and cleaned all the passenges out I put the spring in backwards and had super oil pressure which
caused the filter to blow!! :yes: Took the pan and pump off and turned the spring around and Mister filter stayed on the block!! :rolleyes:

Dave
67 Nova Boy

1)

Did rings, bearings, gaskets etc on a 283 for a friend. Started it up. Low oil pressure once it warmed up. Took it apart, and had assumed it was all original before I opened it, but found out the mains only were ground -.010"

2)

Same friend. Same engine. Putting in the pistons. Put rings on #1 piston, installed it, torqued rod bolts. Put rings on #2 piston, installed it, torqued rod bolts. Repeat all the way to #7. Put rings on piston, notice that in the box there are 3 remaining thin rings that go in the oil ring groove. There should be 2 left as I only have #8 cylinder to go. Now what? Did I forget to install one on a piston from #1 to #6. Went over and over it in my head for hours until I was convinced I had done it all correct on the first 6 pistons. Took a chance, finished up, took the final thin leftover ring remaining and hung it on the wall as a souvenir. That was about 25 years ago and I think that 67 Impala convertible still is running that same engine today, exactly as I assembled it! I now ALWAYS count rings off before I begin!

3)

Assembled an all fresh 327 TH400 combo. Somehow managed to put in one flywheel to crank bolt from a manual trans (slightly longer than from an automatic). Tried starting, engine cranked a bit and locked solid. Tried again and again, same place it locked every time. Tore it all down, found nothing. As I was scratching my head, an older mechanic (I was 18) walked in and when I explained the problem, he figured it out in about a minute.

A while back about 10-12 years ago) I did head gaskets on a toyota four runner V6, a very time consuming job. When I got done the thermostat would not open till the thing was really hot and would then shut again. Well come to find out there are two different head gaskets and I had them on the wrong side of the motor. Worked for free for a day and a half to fix that one. :mad:

ah the blessed Toyota 3vz-e. I did the same headgasket job on my 4runner about a year ago, yeah, very time consuming.

built a 355.. installed new melling HV55 pump... fired the engine on the stand.. blew the oil filter seal in a split sec:eek:... pulled the filter replace with different filter.. same thing:eek:... pulled the filter..... reseated the seal.. tightened the snot out of the filter:D to be able to read the oil gage for a split sec... then noticed the pressure gage was reading 30lbs:confused: with the engine off.. (HUMM:eek::eek: lots a pressure to make the arbor rotate further when the needle hit the stop:confused:). a 270* sweep gage with a stop peg at 100psi.... I fired the engine again.. the gage pegged 100psi then the seal blew again:eek:.... pulled the pan, pulled the pump... removed the pressure relief pin and spring.. the piston would not slide out:mad:.. small tap and the piston moved:bored:... polished the piston and bore a bit.... reassembled the engine.. new gage. fired... 45psi:yes:....

I was 22 a BBC.. 408.. short block I got already rebuilt..because I was going to torcher this engine.. I decided to replace the rod bolts... IN the engine.. with out a resize(did not know better)... the engine was installed in a 77 c10.... ran for over a year before a knock developed...

threw a new set of motown 220 cc 208/160 heads w/ a 64 cc combustion chamber on my 383 without checking compression ratios and the fact that my old heads were a 76 cc combustion chamber.... yeah... big boom about 5,300 rpm shifting into second. I've still got a piece of piston that shot out of the oil pan that still has the KB (Keith Black) logo on it :) expensive lesson, and I'm still trying to get a 383 again...