NPC! Engine problem Options

[ripper911]

I am here to draw upon the wealth of mechanical knowledge on this forum to help diagnose my brothers chevelle. I don't know much about that type of engine.

I believe the engine is a 400ci that has been destroked to 377ci.
It recently started flattening the spark plug gaps. He doesn't think the rods have stretched because they are supposedly high quality. It doesn't sound like the crankshaft is moving around or anything.

He's a mechanic, neither he, his boss, nor anybody else he's asked has been able to figure it out.

[rick 918-S]

Who built the engine? Are the heads shaved? I agree with the others. If the heads were shaved and he is using plugs with a long electrode and domed pistons that would do it. Leaving the crush ring off could do it. and Carbon built up on the piston would do it. But if he has that much carbon he has other issues and it's time for a teardown anyway. I bought a 2.0 914 engine that I thought had a failed seat. Couldn't rotate a complete revolution. When I pulled it apart I found carbon buildup that was stopping the piston on one cylinder.