my very first build, in shop class. I dinged the crank. Went through a couple sets of bearings figuring it out. got the crank polished, and all was well.

Next major prob was in building a ford 302. Got the distributor rotation backwards. OK, not a major problem, but it dam sure stopped my engine from running.

Next : crank ding was in an olds engine, I was building for a bud in the army. I caught that early, didn't destroy the bearing. just took some 400 grit to the ding, ( and the bearing ) worked it smoth, and the engine ran fine. It wasn't performance or anything special. He got plenty of miles out of that mille, so I obviously did ok.

Next major problem was in the 'chicken bone'. This was one of two 74 C10s I bought to make one good one and sell. It was a 350 which gave me no end of trouble. ( called chicken bone cause it was full of Churches' chicken boxes with bones ) SOMEHOW the dam fuel pump push rod bore got dinged up. NO idea how. It would run fine till it warmed up, then the push rod would sieze up. That would have been easy enough to diagnose except that the distributor also had a problem: the pickup coil lost its locator tit and would rock back and forth on its axis. The wires cracked where the left the distributor, and would intermittently short causing misfire. Diagnosing these two conditions simutaneously was a royal bEAtch. I STILL have extra fuel pumps from the trouble shooting process. ( and the engine has a pressure guage now ).

Had another ford 302 which I didn't build, only 'refreshed'. Dam thing ran like a top, but I tore it down to take a look. The bearings were on the outside edge of acceptability ( plastiguage ) so I installed a high volume oil pump. Dam thing had Quaker State build up like you wouldn't believe.. cleaned that gunk out. Learned a real good lesson: I had always cleaned and re-used oil pump pick ups rather than buy new ones. But this time, during cleaning, I accidentally depressed the screen. Popped it out and figured it would be ok. Well, I was wrong. Once the screen in the pickup depresses, you gotta replace it cause it will pop in during normal run. This 'popping in' is a feature designed by the engineers. When it pops in, it reveals the opening in the center, and allows oil to pass ( assuming the screen is plugged ). Anyway, I missed a piece of the nylon timing gear and it got caught in the oil pump. Caused the distributor shear pin to .. shear. major bummer. Had to pull the engine back out to fix.

Out of about 20 or so engines I have built, those are the only major probs that come to mind.