davepl

My engine builder friend just tore down an LS3 crate motor. It was ticking loudly, and it turns out part of #7 piston top is missing (mercifully it went out the exhaust I guess).

Looks like one injector was plugged up and the cylinder got very hot (lean) which must have butted the rings and popped the top off.

But I was really surprised because I thought factory ring end gaps were always big and sloppy. But they're apparently tight enough to butt under extreme circumstances.

So even though this is an LS3, it got me to wondering about the hand-built LS motors:

- Do you they ever file-fit rings or just install them out of the box pregrapped?

bigsapper

Well there's a range in the spec and I don't think (handbuilt == blueprinted).

Bill Dearborn

As far as I can tell hand built is sort of a misnomer. They use a lot of assembly line tools to do the assembly and parts are prepacked to make the process easier. They sure don't let people that pay to assemble their own engine file piston rings and I doubt the regular assemblers do either. Mainly hand built means one person built it Vs several people using the same tools standing along side an assembly line.

Bill

Internets_Ninja

The LS3 rings aren't loose enough to overcome the heat expansion from an extreme lean condition. Same reason you can't lay a lot of boost on a stock LS3/LS7/LT1 and expect longevity.

Also, I don't know the answer to your original question. I would normally think no, they are not hand filed/measured, but we're talking a crate motor here. Not all ring sets are the type that need to be hand filed either. Either way, my first sentence still applies.

Avanti

Short answer... no.