How much noisier should a stock aluminum LS1 block be than the same one with forged rods & pistons? I bought this used last Easter. It's been reliable so far, but I certainly didn't expect this much noise. Now I'm trying to isolate a noise and I wish it were quieter, as it sounds like a diesel.

Are the iron blocks much quieter?

 

Does it do this (dieseling) at all engine speeds? When cold and/or hot?

The rod and crank materials don't mean much one way or the other. Some of the new forged pistons can be run at close piston-to-wall clearances without trouble. I'm wondering where your piston-to-wall clearances are. Any build sheet for this engine?

-Mindgame

 

I wasn't given a build sheet nor did I know to ask for one. I had a couple of experienced LS1 engine builders listen to it and it didn't seem out of the ordinary to them. One said his engine sounded like that too even though it was built to spec.

The dieseling noise is most pronounced at idle speeds.