MaroonMonsterLS1

I've read many different conventions for quench distance. Ranging all over the board from .030 to .055. I'm hoping someone with personal experience or some solid math can chime in here and share their opinion.

I would like to run as tight of quench as possible. The closer the piston gets to the head, the more air is forced out from those areas that have almost no air volume left between them at TDC. This helps turbulent air flow cool hot spots on the head, equalize temp in the chamber, and even sometimes cool the piston because it gets so close to the coolant jackets. I just don't want to press my luck and have a piston kiss the head.

If I assume a .008 out of the hole condition for a stock ls1, and run a .040 HG with 799 untouched heads, i'm about dead on with my 11:1 static goal. This yields .032 quench. I plan on spinning the motor to 6500 rev limit. Seems tight even at that rpm.

I could alternatively mill the heads and run more gasket, but I don't want to leave quench on the table if i don't have to. Aluminum block, piston, head, all seems like it will swell an awful lot.

Does anyone have experience with quench this tight, good or bad? Does anyone have a reason to deter me from this and make me go "looser"

98cherrySS

iTrader: (2)

I'm running similar compression on a valve relief piston and Advanced Induction recommended a .036-.041 gasket. I'm .005" out of the hole and went with the .040 compressed thickness cometic gaskets (.035 quench) and have been driving on it for 3 years without issue. I beat on the car a good bit as well. 1/4 mile and 1/2 mile racing as well as 2500 street miles a year.

1970camaroRS

iTrader: (8)

.032 is perfect.

A.R. Shale Targa

iTrader: (2)

On an all aluminum application : .032" at room temp becomes about .040 at operating temp.
An old school GEN I. all iron will kiss the head at .031"-.032".

pantera_efi

iTrader: (1)

There is the case of piston/wall clearance.
A 2618 alloy piston requires more wall clearance thus more movement at TDC from side to side.

Tight pistons, high silicon, can use a lower Quench Distance.

There is a piston speed consideration, caused by RPM/Stroke values.

I like a .007" "proud" deck, alloy block, 4.00" crank, .038 MLS, 4032 alloy N/A, 7000 RPM.

Lance

MaroonMonsterLS1

I am going to have the factory hyper flat tops, probably won't spin over 6500, and after putting a bridge and measuring exactly, will shoot for as close to .032 quench as possible with a 3.910 bore MLS gasket. Hope this is safe!

DavidBoren

I was also going to suggest as small of a bore head gasket as possible, if your intentions are to specifically reduce the dead space air volume. It looks like you are on top of that though. And without spinning past 6500rpms, I do not see you having a problem.

98cherrySS

iTrader: (2)

I think 3.910 was the closest I could find when I was building mine.