Thread: Caamshaft Selection

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1. Squish (also called quench) is the measured distance from the crown of the piston to the flat surface of the cylinder head at top dead center. The tighter this dimension, the more aggressively the fuel/air mixture will be "jetted" across the chamber, leading to superior mixing and the elimination of dead spots in the chamber. The area between the crown and the head is also a dead spot where combustion does not occur, so the smaller and tighter that area, the more power will be produced and the cleaner the emissions will be.

2. I have no idea. Ask your engine builder.

3. Richard, I think you're very confused and that you need to step back and reevaluate your goals. In one breath, you're telling us that you want a "driver" (here's your quote: "I want low speed drivability") and in the next breath you're telling us that you are planning on shifting at some insane rpm's (here's your quote: "I am looking to keep shift points between 5600-6000 rpm").

4. It's also dependent on the dyno used, the dyno operator, the shop header design used, the fuel, the fuel curve, the ignition curve, the components used in the build, the clearances used in the build, the ambient temperature and humidity at the time of the test, etc., etc.

5. Your builder is right on the money. If you have the squish optimized and are running less than 11.0:1 c.r., then you can run on pump gas with no detonation. It's all about cylinder pressure. You can run more cylinder pressure on the same gas if you optimize the squish. With a deck height of 0.015", you would want to use a gasket that would compress at between 0.020" and 0.025" in order to yield a squish of 0.035" to 0.040".

"I thought that a thicker head gasket would reduce running compression and reduce the chance of detonation"

Not so. A thicker gasket will INCREASE the tendency toward detonation. Even though it will increase static compression ratio slightly, a thinner gasket will reduce the squish dimension and reduce the tendency toward detonation.