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View Full Version : Cylinder Decompression

CrazedPanda
10-20-2006, 09:36 PM
Soon im going to be swapping a DOHC KA into my 1990 240SX, the plan is to add a turbo. Someone told me it would be a good idea to decompress the cylinders by putting 2 headgaskets in it. Im pretty sure Jun/Topsecret makes an extra thick gasket for this purpose but its somewhere around $600. Has anyone heard of using 2 headgaskets? I guess its done to imprezas also when adding a turbo.
shayrgob240
10-20-2006, 10:07 PM
idk, I personally ? the sealing capabilities of 2 HG's put together. Aren't there any copmanies that make an extra thick gasket? lol
CrazedPanda
10-20-2006, 10:16 PM
I didnt think 2 would make a good seal but he said it would be fine... anyways I think either Jun or Top Secret make extra thick ones, but they arent companies you just place an order with. They deal mainly with only racing.
g6civcx
10-20-2006, 11:28 PM
If you do decide to try, please let us know if the engine has issues.
bardabe
10-20-2006, 11:55 PM
save yourself the time/money/hastle. give cometic a call I am sure they can make you a custom gasket. its what I did. running a 1.2mm 87.5mm bore gasket ion my SR. im sur ethy cna build you a 2.4mm one if you wanted to.
CrazedPanda
10-21-2006, 07:39 PM
I talked to my friend again and he told me that there is a special "stackable" head gasket specificly made for using more than one. Also is it really necessary to use a thicker headgasket? How much of a decompression would it give me?
bardabe
10-22-2006, 12:14 PM
they are called multy layer Head gaskets. exacly what I just told you about. decompression is minimal a thick head gasket is not going to take you from 9:1 to 8.5:1. but it makes a diference just not bug. its mostly that the headgasket can take a royal beating. and HP before blowing to bits and shits.
PoorMans180SX
10-22-2006, 01:32 PM
I talked to my friend again and he told me that there is a special "stackable" head gasket specificly made for using more than one. Also is it really necessary to use a thicker headgasket? How much of a decompression would it give me?

You need to stop listening to your friend:smash: . Stackable headgaskets! Are you kiddin me?

Get a cometic. Done. Just get stock thickness, it stands better against boost anyway and doesn't ruin your quench area.