Quench and compressed thickness
11-13-2008, 12:53 PM
#1
Drifting
Thread Starter
Quench and compressed thickness
I sent this over to Tony at AFR, but wanted to see what other members thought. I'm no engineer, so keep that in mind:
I'm curious if I made the correct selection for my head gaskets. I'm running a stock 1986E short block, with AFR 65cc 1040 195's. This is an F/I application with a max limit of 10psi.
I used the AFR recommended Fel-pro 1003 head gaskets with .041 compressed thickness. Given the factory L98 deck height of .025" in the hole, is my quench area, .066, too high?
Here are my cam specs:
224/234 @ .050 (282/292 advertised), .465/.488 lift (.496/.520 with 1.6 rollers), and 114 lsa
I calculate my static CR at 9.42 (if my number of 7cc factory 1986 piston volume is correct). If I change compressed thickness to get .040 quench, my static increases to 9.98 with a compressed thickness of .015. Piston to valve clearance issues at this level?
I'm curious if I made the correct selection for my head gaskets. I'm running a stock 1986E short block, with AFR 65cc 1040 195's. This is an F/I application with a max limit of 10psi.
I used the AFR recommended Fel-pro 1003 head gaskets with .041 compressed thickness. Given the factory L98 deck height of .025" in the hole, is my quench area, .066, too high?
Here are my cam specs:
224/234 @ .050 (282/292 advertised), .465/.488 lift (.496/.520 with 1.6 rollers), and 114 lsa
I calculate my static CR at 9.42 (if my number of 7cc factory 1986 piston volume is correct). If I change compressed thickness to get .040 quench, my static increases to 9.98 with a compressed thickness of .015. Piston to valve clearance issues at this level?
11-13-2008, 03:52 PM
#2
Race Director
Did you read my "Head Gasket Thickness Poll" thread -- which is still on the first page of this (C4 Tech) forum?
11-13-2008, 04:31 PM
#3
Burning Brakes
Yes, MAJOR problems! You must sell me your heads immediately! 
I think the .015 gasket will raise your compression too high for what most call a good safe compression ratio for a forced induction engine, but I have no experience with forced induction. I researched it alot though.
I think the .015 gasket will raise your compression too high for what most call a good safe compression ratio for a forced induction engine, but I have no experience with forced induction. I researched it alot though.
11-13-2008, 04:50 PM
#5
Drifting
Thread Starter
11-13-2008, 04:58 PM
#6
Drifting
Thread Starter
Tony's response:
I would run what you have....sounds like a good forced induction set-up to me. Ideal "quench" is not as critical on a forced induction set-up and I prefer the static CR to be where it is with your current set-up assuming your running pump gas of course.
Looks good....
Tony
I would run what you have....sounds like a good forced induction set-up to me. Ideal "quench" is not as critical on a forced induction set-up and I prefer the static CR to be where it is with your current set-up assuming your running pump gas of course.
Looks good....
Tony
11-13-2008, 10:20 PM
#7
Safety Car
Tony's response:
I would run what you have....sounds like a good forced induction set-up to me. Ideal "quench" is not as critical on a forced induction set-up and I prefer the static CR to be where it is with your current set-up assuming your running pump gas of course.
Looks good....
Tony
I would run what you have....sounds like a good forced induction set-up to me. Ideal "quench" is not as critical on a forced induction set-up and I prefer the static CR to be where it is with your current set-up assuming your running pump gas of course.
Looks good....
Tony
Quench is far less important with a forced induction motor.
More important things IMO
1. Proper SCR and DCR.
2. Keeping deck surfaces as thick as possible.
3. Utilizing the best head gasket you can afford.
4. Keeping the top ring down in the cyl.
Getting your SCR/DCR lower is more a important factor in controling detonation in a forced induction motor than quench will ever be. Since you already have the heads and the short block, you do what you have to do with the head gasket...
Will
