Cylinder Decompression - Zilvia.net Forums | Nissan 240SX (Silvia) and Z (Fairlady) Car Forum

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

Quote:

Originally Posted by CrazedPanda

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

. 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.

10-20-2006, 09:36 PM	#1
CrazedPanda Join Date: Oct 2006 Location: New Hampshire Posts: 10 Trader Rating: (0) Feedback Score: 0 reviews	Cylinder Decompression 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. __________________

10-20-2006, 10:16 PM	#3
CrazedPanda Join Date: Oct 2006 Location: New Hampshire Posts: 10 Trader Rating: (0) Feedback Score: 0 reviews	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. __________________

10-20-2006, 11:55 PM	#5
bardabe Post Whore! Join Date: Aug 2005 Location: SoCal Age: 35 Posts: 4,719 Trader Rating: (10) Rides Gallery: bardabe Feedback Score: 10 reviews	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. __________________ Review Thread

10-21-2006, 07:39 PM	#6
CrazedPanda Join Date: Oct 2006 Location: New Hampshire Posts: 10 Trader Rating: (0) Feedback Score: 0 reviews	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? __________________

10-22-2006, 12:14 PM	#7
bardabe Post Whore! Join Date: Aug 2005 Location: SoCal Age: 35 Posts: 4,719 Trader Rating: (10) Rides Gallery: bardabe Feedback Score: 10 reviews	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. __________________ Review Thread

10-20-2006, 10:07 PM	#2
shayrgob240 Zilvia Junkie Join Date: Jul 2003 Location: gurnee, IL Age: 40 Posts: 441 Trader Rating: (0) Feedback Score: 0 reviews	idk, I personally ? the sealing capabilities of 2 HG's put together. Aren't there any copmanies that make an extra thick gasket? lol

10-20-2006, 11:28 PM	#4
g6civcx Post Whore! Join Date: Apr 2004 Location: Virginia, USA Posts: 5,764 Trader Rating: (5) Feedback Score: 5 reviews	If you do decide to try, please let us know if the engine has issues.