subject says it all...

 

here is my take on it. . . . . .

with quench being .070 or more, the piston at TDC will have this much room between the piston and quench pad on the head. This will allow for the A/F mixture to stay in this area and burn at a slower rate or later time than the A/F that is in the chamber. It can also have puddles of air and fuel instead of a good mixture.

When the quench is tighter than this (.035 to .045) you will have the piston closer to the head at TDC and at it will cause the A/F mixture to be forced from the area between the piston and quench pad. When this happens, it causes the mixturte to be very turbulent, mixed well and packed into a smaller area (the chamber only). This will allow more to burn at one time and less to be wasted.

I believe that you want the quench as tight as possible without the piston hitting the head. Parts stretch and pistons rock so RPM, rods (steel or aluminum), piston diameter, side clearance and rock, etc will all need to be taken into consideration if you are trying to get everything that you can.

Around .040 is pretty much what everyone shoots for with steel rods and 7000 RPM. Fel Pro gaskets are .038 to .041 and if you zero deck the block, you will be safe. I have ran +.005 deck ht with Fel Pro gaskets at 7500 RPM and not had problems but it depends on how lucky you feel.

If you are dealing with stock bottom ends and have the piston down in the hole .040 to .100, you will NEVER get the quench right until you swap pistons. If the piston is .030 or less in the hole, you can correct alot with thinner head gaskets.

NightTrain66
(Lloyd)

 

 

Good write up Lloyd, that post says it all.

 

wow...thanks for the info!

so what is the quench on a stock lt1?

so i guess that using a thicker gasket on a blown motor to help reduce compression is a big no-no then huh?

 

Well add up the gasket thickness and .025 and you'll be close probably around .060-.070

That's one reason the Imppy gasket it so nice, helps the quench and compression.

Yeah a bigger gasket is a BIG NO NO

Bret

 

ok...thanks for the info guys!

 

For a dirt-cheap bolt-it-together combo that gives good quench height look into a set of Keith Black hypereutectic pistons (they sit ~.017" in the hole with no block decking) and use a GMPP .028" compressed thickness head gasket (dirt cheap- $23 for a set of 2). ~.045" quench height right outta the box.

I've really gotten good results with Keith Black pistons for years now. Watch their special ring gap recommendations and they'll live a long long life. Heck, I'm using them in my blower motor right now (which I don't recommend, but obviously it can be done). I've also used the GMPP .028 head gasket in several motors now and have ZERO complaints (including in my blower motor). They are as good or better than the Fel Pros (my previous favorite gasket).

The combination of the two works well and, obviously, gives you good quench in a bolt-it-together combo for the bucks-down street performance junkie.

 

Why not use more head gasket all the ricer do it .

 

FYI: FelPro steel head gaskets compress to 0.017" when properly
torqued.

I mic'd my set after removing them last year.

Now...try to get the part number from me

 

FEL PRO 1094

http://store.summitracing.com/partde...1094&view=2047

Bret

 

http://store.summitracing.com/partde...1094&view=2047
I know for a while they had to have stoped makeing for a while I told a friend about them and when I went to show them to him a few weeks after I first saw them they were gone with out a trace???
Better get em before they go a way.

 

Just thought I would mention this for all the 4th gen Camaro guys....
Those gaskets are not for LT1's.