MILD THUNDER

iTrader: (3)

I run about .050 on my blown 468's. One block came in around 0 deck, and the other around .008 out of the hole. so engine 1 got a .051 HG, the other a .060 HG.

http://www.competitionproducts.com/P...uctinfo/66798/

Budman II

iTrader: (1)

Well, considering that mine is a NA engine with only about 8.7:1 compression and a max RPM of about 52-5400 RPM, do I stay with the tighter .038 quench, or go with the greater safety margin of.047? One of the reasons that I wanted to go with the thinner head gasket was to get my compression ratio as high as possible, considering that I am struggling on that front to begin with. But now I am wondering if I am exposing myself to risk of damage.

MILD THUNDER

iTrader: (3)

I'd stick a standard .039 head gasket on a call it a day

adk61

iTrader: (5)

agreed

blue thunder

The word quench comes from the idea that the top of the piston is cooled (quenched) as it stalls at the top of its stroke and is in near contact with the head. .038-.040 is where I like to put them even though it is said you can go tighter. I like a little margin in case the engine gets over revved. I don't see how this cooling effect is not good n/a or boosted.

Budman II

iTrader: (1)

Not trying to completely hijack the thread, but wondering if deck height measurement is always taken along the edges of the piston. I don't have access to a depth micrometer, so I tried measuring it both with the straight edge / feeler gauge method and with a dial indicator. In both cases I noticed that the top of the piston (Mahle flattop) has about .001 crown across the middle. I assume this is normal, and that the high point will be inside the combustion chamber so clearance at this point is not an issue, right? How far in along the edge do you want to take the measurement - half inch or so?

Thanks.

blue thunder

I take one measurement on each side of the piston parrellel with the wrist piin, then I average those two figures. I always use a depth micrometer.

supermx96

Last year i have run my blower engine at .050, this year i will try to close them to .040 after some research it's look like that is the way to go.

At .050 last year i get some sing of detonation after a wot run, when i shut off the engine the engine still to make some explosion without ignition but i need to say that i haved projected plug when that symptom occur.

So at .050 with non projected plug do you have nitice that symptom?

I am pretty sure the plug was the cause over the quench in my situation.

MILD THUNDER

iTrader: (3)

Nothing like that here. Sounds like it was "dieseling'' on you. I'd definitely look at the plugs.

What plugs are you running??

Black Baja

iTrader: (2)

I run the piston .005 to .007 out of the deck of the block and use a .039 or .040 gasket. That gives you .032 to .034 clearance. If you tell some of the sprint car guys that you need a quench distance of .040 they are gonna look at you like your crazy. They build there motors much tighter and the guys that really know what they are doing can just barely get the pistons to touch the head. The key is to squeeze the air and fuel out of the quench area into the combustion chamber. The theory on the quench area is starting to change though. Pistons are being made with inverted domes and a couple degrees of slope to push fuel away from the quench. Your real big motors have the pistons in the hole up to .200 thoose real big motors are also running 0 degrees of timing to get them to live...