tim burks

well guys i've ran into piston availability problem with my 6.0 build. seems that a stock stroke and 6.125 rod makes it hard to find a off the shelf piston at 11:1 compression on a L92 head. I did however find a 11.7 to 1 compression off the shelf piston for my stroke/rods. my question is how would it like 93 octane pump gas with the compression that high?

speedtigger

iTrader: (16)

what are your cam specs again Tim? and how much stall converter?

fast89stang

iTrader: (2)

Cam will determine how well it will handle that compression. Cam can be designed so it will work.

tim burks

BTR cam 235/248 @.50 .610/.595 lift on 111+4

im using PTC 4000 converter

fast89stang

iTrader: (2)

Im no cam expert, lol. Speed understands them much better than me. i always leave all that to FTI. But if i had question, I would just contact grinder and see what he says. i know for a fact most of them wont just try and sell you one if not needed. My buddy, Lucas walker changed his motor up some, added cubes and compression. Instead of Ed trying to sell him a new cam, he told him it wasnt enough change to warrant a new cam, just to run what he had. I am sure Brian can tell you if it will be fine and will bleed off enough cylinder pressure.

speedtigger

iTrader: (16)

I would think that with a 4000 converter you might be okay if you are conservative on the timing and stick to 93. It is pushing it though. The EFI guys with later intake valve close can and do get away with more, but us carb guys can be more limited with the cams that we run.

If you have a lock up torque converter it will rattle if you lug the engine at low RPM.

You could have your cylinder head guy soften up the combustion chambers and remove a few CCs maybe unshrouding the valves a bit in the combustion chamber.

tim burks

thanks speedtigger, Im gonna give it a shot and see what happens. its got solid domes so we may cut the piston a tad.

tim burks

the other option I have is a flat top, so it would be around the 10 to 1 range. just hate to leave power on the table ya know

Doug G

Can mill the heads ?
.050 mill on my LS3 heads bumped me about 1 point on a stock LQ4 bottom end. Your 10:1 and a .030 to .050 cut should get you close also ??

Measure

speedtigger

iTrader: (16)

That is really easy to do before the engine goes together. I have cut many pistons down over the years. I am not saying you should, but I would be tempted to run it and see how it does. I have thought about bumping mine up to 11.25.

tim burks

just to update, I swapped my 6.125 rods for a set of 6.100's. the got a set of wiseco that are 11.1 with my l92 heads.

speedtigger

iTrader: (16)

Tidy solution. I look forward to seeing how it runs.