I have seen the common ones being 0.030 and 0.074, refered to as NA and boosted respectively... and which pistons are you using?

I have wiseco pistons and I am going with a thicker head gasket, 0.045 will increase quench to 0.037 (stock value) and apparently 0.035 is opitmum.. but the 0.074 (boosted) head gasket, is it made for wiseco pistons or stock pistons.. cause I don't want to open quench up too hgh, but I think it is my issue, and I am looking for some experienced answers and some "I have this........ and it works great" answers, thanks

-Garrett


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so I am the only one boosted hey.. lol


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I have to highly doubt the quench is .037 stock, where did you see that value? The LN2 for instance is about .075-.080 or somewhere around there. With cast rods and pistons, .037 would be a major risk for an OEM to take, and we all know GM doesn't take risks with the grocery-getters.
The 'optimum' value is .000", how close you can safely get to that depends on the parts and build design.



fortune cookie say:
better a delay than a disaster.

optimum is 0.035,

as for stock, I don't know where I got that number from.. I think I grabbed a thickness of something that seems wrong.. I agree with 0.075 stock...

any tighter than 0.035 greatly increases detonation instances.


HP Tuners | Garrett T3/T04B | 2.5" Charge Pipes | 2.5" Downpipe | 650 Injectors | HO Manifold | Addco front/rear | Motor Mounts | HKS SSQV | Spec stage 3 | AEM UEGO Wideband | Team Green LSD | FMIC | 2.3 cams | 2.3 oil pump swap | 280WHP | Now ECOTECED

damn it I need to be premium again so I can edit, I was going to add this, and the guys credentials are as follows:

3 Winston Cup Poles
5 Winston Cup front rows
2 Winston Cup event records
1 Winston Cup track record
8+ NHRA national records
Over 100 Fast times at local tracks

Quote:

Excessive cylinder pressure will encourage engine destroying detonation with no piston immune to its effects. The goal of performance engine builders should be to build their products with as much detonation resistance as possible. An important first step is to set the assembled quench distance to .035". The quench distance is the compressed thickness of the head gasket plus the deck height, (the distance your piston is down in the bore). If your piston height, (not dome height), is above the block deck, subtract the overage from the gasket thickness to get a true assembled quench distance. The quench area is the flat part of the piston that would contact a similar flat area on the cylinder head if you had .000" assembled quench height. In a running engine, the .035" quench decreases to a close collision between the piston and cylinder head. The shock wave from the close collision drives air at high velocity through the combustion chamber. This movement tends to cool hot spots, average the chamber temperature, reduce detonation and increase power. Take note, on the exhaust cycle, some cooling of the piston occurs due to the closeness to the water cooled head.

If you are building an engine with steel rods, tight bearings, tight pistons, modest RPM and automatic transmission, a .035" quench is the minimum practical to run without engine damage. The closer the piston comes to the cylinder head at operating speed, the more turbulence is generated. Turbulence is the main means of reducing detonation. Unfortunately, the operating quench height varies in an engine as RPM and temperature change. If aluminum rods, loose pistons, (they rock and hit the head), and over 6000 RPM operation is anticipated, a static clearance of .055" could be required. A running quench height in excess of .060" will forfeit the benefits of the quench head design and can cause severe detonation. The suggested .035" static quench height is recommended as a good usable dimension for stock rod engines up to 6500 RPM. Above 6500 RPM rod selection becomes important. Since it is the close collision between the piston and the cylinder head that reduces the prospect of detonation, never add a shim or head gasket to lower compression on a quench head engine. If you have 10:1 with a proper quench and then add an extra .040" gasket to give 9.5:1 and .080" quench, you will create more ping at 9.5:1 than you had at 10:1. The suitable way to lower the compression is to use a dish piston. Dish (reverse combustion chamber), pistons are designed for maximum quench, (sometimes called squish), area. Having part of the combustion chamber in the piston improves the shape of the chamber and flame travel. High performance motors will see some detonation, which leads to preignition. Detonation occurs at five to ten degrees after top-dead-center. Preignition occurs before top-dead-center. Detonation damages your engine with impact loads and excessive heat. The excessive heat part of detonation is what causes preignition. Overheated combustion chamber parts start acting as glow plugs. Preignition induces extremely rapid combustion and welding temperatures melt down is only seconds away!

HP Tuners | Garrett T3/T04B | 2.5" Charge Pipes | 2.5" Downpipe | 650 Injectors | HO Manifold | Addco front/rear | Motor Mounts | HKS SSQV | Spec stage 3 | AEM UEGO Wideband | Team Green LSD | FMIC | 2.3 cams | 2.3 oil pump swap | 280WHP | Now ECOTECED

i heard somewhere that the thickness is .035-.037 stock for 2.4.....

as for gasket im using the cometic boosted h/g no problems, also running rapid fire#5 plugs @ .032 gap



R.I.P. Brian Klocke, you will never be forgotten

Yes, I already read that in your other thead (didn't learn anything, but I read it). NOTHING in there says a quench tighter than .035 will increase detonation. The only reason .035 is suggested is due to mechanical (not thermal or fluid) limitations...aka rod stretch, piston rock, bearing wear, and clearances within the assembly. In an ideal engine, the optimum quench distance would be 0, zilch, none.
You tried disagreeing with me in the other thread as well, but the article you posted confirms what I said (going to a thicker gasket will increase your detonation).
Read, then comprehend, por favor.
If you want to determine the stock quench, you just add the distance the piston sits below the block deck at TDC to the compressed headgasket thickness.



fortune cookie say:
better a delay than a disaster.

Quote:

If you want to determine the stock quench, you just add the distance the piston sits below the block deck at TDC to the compressed headgasket thickness.

obviously

and thicker headgasket will not necassarily increase detonation. But this is research, I will post from experience when hopefully, it fixes my issue. We are arguing about what we have read..


HP Tuners | Garrett T3/T04B | 2.5" Charge Pipes | 2.5" Downpipe | 650 Injectors | HO Manifold | Addco front/rear | Motor Mounts | HKS SSQV | Spec stage 3 | AEM UEGO Wideband | Team Green LSD | FMIC | 2.3 cams | 2.3 oil pump swap | 280WHP | Now ECOTECED