Engine Failure/ Thrown Rod Just Rebuilt

[sparky52386]

Recently i just got done rebuilding my engine. The list includes, crankshaft machining/remanufacturing, rod bearing surfaces machined, all new crank/rod bearings (clevite), Evo 3 16g Turbocharger, Evo 3 Exhaust Manifold, and all upper and lower seals. Two days after driving around with no problems and about 400 miles on the engine i was cruising down the road going about 75mph when i noticed the oil pressure had dropped to idle level. I started slowing down fearing the worst when i slowed down i heard a knocking sound. I stopped on the side of the road the engine was smoking and oil was spewing out. We noticed the oil pan had a hole in it about 1/8th of an inch around. I beleive i threw a rod due to the shape of the hole. Like the rod cap cam off. The engine was still running when i stopped so i didnt have complete engine failure. I have yet to pull the pan off. I was wondering what the cause could be. I asked my autoshop teacher what it could be. He said it might have been because i re-used the Rod cap nuts, he said that you are not supposed to reuse the nuts because they have a certian elasticity and once they are torqued down they change elasticity. It was torqued once from factory once at the machine shop and once at my house. Any Ideas? or knowledge about this?

 

[spoolints04]

I'd never reuse rod bolts more than once, especially tiny 7 bolt rod bolts. It's very cheap insurance to have the rod bolts replaced with good bolts (ARP) and have the rods resized at the same time. Remember, almost every machanical part out there has a fatigue life. Bolts for instance, everytime you torque them they stretch. Once the bolt is stretched more than I think .006 it's time to trash it.
Maybe you just forgot to torque one, I always use a yellow paint marker and mark them as I torque them.
Best of luck with it.

 

[Maglin]

I feel for you man... that sucks.... did you Mic your journals and bearing clearances before you installed everything?? Or did you use plastigauge??? but I'm pretty sure those old Rod Bolts could have been the cause...

 

[sparky52386]

We Plastigauged it and we did check the side to side travel of the crank etc. The mechanic that did it has done many engines, but never a foreign car. They nuts were all torqued down, i am sure of that i watched most of the rebuilding process. Could the cylinder on the block be damaged from the volatile motion?

 

[Mirage2LTurbo]

After I torqued my Eagle's down, I went back through twice and made sure they were all in spec after rotating the assembly around a few times and taking a lunch break. Otherwise, I always seem to forget something when I rush

 

[Suparata]

Sparky ,
Did you find out what went wrong?