DerrenC

I'm trying to resolve a knock in my engine. I've been getting help from members at TGO in this thread:

http://www.thirdgen.org/techboard/lt...ns-knocks.html

but maybe my questions more appropriately belong here.

That thread chronicles how it sounded wrong when it first fired:



and how I ended up pulling the heads (after pulling the pan and checking rod bearings) to find this:



The rings looks to be intact, and there is a wide shallow gouge on the cylinder wall opposite the piston damage. Valves appear fine.

So my question for experienced LS1 owners is this: As bad as that looks, would it cause the knock heard in the video?

c0ncEpT

iTrader: (4)

It more than likely has something broken in the valvetrain. Sounds just like my buddys car when a rocker lost all the needle bearings.

All the cars I have seen lose a ringland have ran decent -1 cylinder. My friend drove his car 70 miles home from the track with a broken ringland. Other than a slight miss and a back fire it ran as quiet as before.

DerrenC

So far the valvetrain looks fine. I pulled the rockers and pushrods and they were fine. I pulled the heads off to replace the lifters when I found the busted piston.

I figured I had found my problem, but yeah, I wondered if it would actually cause a knocking noise or not.

Has anyone ever had a busted piston like this cause a discernible knock from the engine?