HG thickness on SR question - Zilvia.net Forums | Nissan 240SX (Silvia) and Z (Fairlady) Car Forum

Cone · 09-15-2007, 03:50 PM

I did a search and I couldn't find anything, so I'm planning on doing a little head rebuild on my SR. Probably just the head, but the block if I need to, since my motor has been burning oil since day one of my swap. I just have a T28 and I might want to boost it a little higher probably no more than 15 or so. I probably aren't going to do anything crazy to it, like a huge turbo or anything, nor am I aiming for over 300 hp either. I just want to keep it reliable.

What would be a good thickness for a head gasket? I think I'm going to go cometic.

rps13drift · 09-15-2007, 03:54 PM

I heard of alot of horror stories with the cometic! When i did a rebuild of my sr20 i retook the head off to replace my cometic with an apexi 1.1mm headgasket. You cant go wrong with the apexi! from what i hear its the best on the market

Cone · 09-15-2007, 04:06 PM

I did a few searches, and it seems like cometic is allright. It seems though that people like the Apexi though a lot, but it's twice as much.

rps13drift · 09-15-2007, 04:12 PM

Quote:

Originally Posted by Cone

I did a few searches, and it seems like cometic is allright. It seems though that people like the Apexi though a lot, but it's twice as much.

Spend your hard earned money right the first time and you wont be sorry. I personaly love the apexi unit and every one that has one loves them. I heard of alot of headgasket failures from greddy and cometic over the past few years and when it comes down to something that seals your motor i just wouldnt want to take any chances.

Koopa Troopa · 09-16-2007, 07:54 AM

Stock headgasket size is 1.0mm.. I recommend staying with that size. No need to lower or raise your compression when your motor is stock

Sileighty_85 · 09-16-2007, 08:10 AM

Power Enterpirse Kicks ass Im running a 1.5 mil on mine there right up there next to Apexi, Seriously though Ive talked to many shops when I was ordering my H/G they advised me to lean away from Cometic but maybe it was because of my set up I was running.
I'd go with what RSP13drift said do it right the first time and then you'll have no worries when it come to that time if you ever want to upgrade to a bigger turbo.

PoorMans180SX · 09-16-2007, 01:45 PM

Quote:

Originally Posted by Koopa Troopa

Stock headgasket size is 1.0mm.. I recommend staying with that size. No need to lower or raise your compression when your motor is stock.

^^He's right. You don't need a thicker HG to run 15psi on a SR

Thicker headgaskets are a crutch anyway.

240SX2high2aim · 01-05-2008, 02:44 PM

Hey man I dont get what is the difference between different head gasket sizes. What is could if you want more boost bigger or smaller plz explain.

Addicted2Kouki · 01-05-2008, 02:49 PM

Quote:

Originally Posted by 240SX2high2aim

Hey man I dont get what is the difference between different head gasket sizes. What is could if you want more boost bigger or smaller plz explain.

bigger... creating more space... lower compression.

Dousan_PG · 01-05-2008, 02:52 PM

ive been using a cometic for like 1 year now
running boost at track events (drift) anywhere from .9 bar to 1.5 bar depending what i want it at for the day
last few events have been 1.4 bar haha

it works great
9:1 compression rebuilt engine.

jspaeth · 01-05-2008, 03:12 PM

Quote:

Hey man I dont get what is the difference between different head gasket sizes. What is could if you want more boost bigger or smaller plz explain.

WTF this dude has now posted in 2 threads that are 2 and 4 months old

ugh

Somehow I don't think he's 47

Doluck · 01-05-2008, 03:58 PM

I love the apexi, it has done me way better than cometics.... (22psi daily on a .08x86mm)

I would stay with .08 or 1.mm x86mm unless your looking for 600+hp.

Problem with cometic is they sell 1 kinda gasket for sr20 its a 88.5mm bore for a fwd, its has about 17 diffrent part numbers for the diffrent car. If you call them they will tell you its the same gasket and it wont hurt anything. That BS.. the fwd is alittle diff. from the rwd. It can be used tho..
Anyway.. other issues are no fire ring, oil holes that dont line up. because the hg being to large pitting, erosion from detonation happens to the top of the cylinder walls, i have even see the walls cave in..

you can find about 1000000 threads on all of these issues on FA by Mazworx, and many others that mave built more motors than me.. ive aonly done about 8

smelly240 · 01-08-2008, 05:26 PM

riiight...
except they have in stock at multiple places 86.5 mm bore gaskets from cometic for s1X. I have never had a problem with my 86.5mm bore cometic - which apparently must not exist (i got mine the day after i ordered it from extreme psi btw)

all my oil holes lined up perfect and the everything to date is fine.

for the thread bumper guy - thicker HG lowers compression so u can safely increase boost... u want the HG bore within .5 of ur bore size in most cases

PoorMans180SX · 01-08-2008, 06:21 PM

Don't buy a thicker head gasket. It's dumb. The proper way to lower/raise compression is with different pistons.

There is no need to lower your compression on a stock SR20DET as it's already relatively low at 8.5:1. As you can see Dousan runs a 9:1 motor.

Thicker headgaskets decrease quench area, making the air/fuel charge less homogeneous and upsetting combustion smoothness. Lower compression also decreases off-boost torque and throttle response.

Spend your money on a good stock-thickness headgasket and get a good tune. Your engine will thank you.

Doluck · 01-08-2008, 08:18 PM

Its not 86.5.. if you messure it you will find its 88.5mm

smelly240 · 01-09-2008, 04:23 AM

screw u ass - its 86.5 - here

notice you can pick the bore size. OMG no way!??!

stop looking at threads mazworks posted in 05 and get with it...

it also makes the quench area bigger... the thing that upsets it is the oversized HG bore. Which as i just posted - isnt a problem (since cometic does make the smaller bore gasket - despite what the guys on FA thought*)

Hooorahh! · 01-09-2008, 09:00 AM

i would honestly go with a tomei / apexi whatever 1.2mm and call it a day ...
its just the safest way to go ... u might say u want 15 psi now but then later u might want 18-20 so just to be safe and not have to spend more money in the long run

tr_racing · 01-09-2008, 09:27 AM

I just ordered a ApexI 0.8mm x 86mm with ARP headbolt for my S15 SR20.

Kevin..

Koopa Troopa · 01-09-2008, 01:48 PM

I have a Tomei 1.2 because my head has been decked 2mil and it's been decked before I got it too... Bigger head gasket to keep my pistons from slappin my valves..

09-15-2007, 03:50 PM	#1
Cone Leaky Injector Join Date: Jan 2006 Location: Portland, OR Posts: 85 Trader Rating: (0) Feedback Score: 0 reviews	HG thickness on SR question I did a search and I couldn't find anything, so I'm planning on doing a little head rebuild on my SR. Probably just the head, but the block if I need to, since my motor has been burning oil since day one of my swap. I just have a T28 and I might want to boost it a little higher probably no more than 15 or so. I probably aren't going to do anything crazy to it, like a huge turbo or anything, nor am I aiming for over 300 hp either. I just want to keep it reliable. What would be a good thickness for a head gasket? I think I'm going to go cometic.

09-15-2007, 03:54 PM	#2
rps13drift Zilvia FREAK! Join Date: Oct 2006 Location: NJ BRO!!!! Age: 39 Posts: 1,194 Trader Rating: (6) Rides Gallery: rps13drift Feedback Score: 6 reviews	I heard of alot of horror stories with the cometic! When i did a rebuild of my sr20 i retook the head off to replace my cometic with an apexi 1.1mm headgasket. You cant go wrong with the apexi! from what i hear its the best on the market __________________ http://allies-drift.blogspot.com/

09-16-2007, 07:54 AM	#5
Koopa Troopa Post Whore! Join Date: Sep 2006 Location: 北谷著, 沖縄県、日本 Posts: 2,565 Trader Rating: (3) Feedback Score: 3 reviews	Stock headgasket size is 1.0mm.. I recommend staying with that size. No need to lower or raise your compression when your motor is stock __________________ Buy my Stillway shifter!

09-16-2007, 08:10 AM	#6
Sileighty_85 Post Whore! Join Date: Dec 2006 Location: Misawa, Japan Posts: 6,815 Trader Rating: (8) Feedback Score: 8 reviews	Power Enterpirse Kicks ass Im running a 1.5 mil on mine there right up there next to Apexi, Seriously though Ive talked to many shops when I was ordering my H/G they advised me to lean away from Cometic but maybe it was because of my set up I was running. I'd go with what RSP13drift said do it right the first time and then you'll have no worries when it come to that time if you ever want to upgrade to a bigger turbo. __________________ 後輪駆動車１番 1989 Built SR GT2871R -363whp 1998 S14 W/RB25- 250ish (For Now) 1986 SR86 - 200ish 1990 R32 GTR - 320hp Don't Buy Engines from JDM-Online http://zilvia.net/f/businesses/207457-jdm-online.html Don't Buy XS-Power or SSAC Shit

01-05-2008, 02:52 PM	#10
Dousan_PG Post Whore! Join Date: May 2002 Location: Orange County, California Age: 46 Posts: 16,640 Trader Rating: (23) Rides Gallery: Dousan_PG Feedback Score: 23 reviews	ive been using a cometic for like 1 year now running boost at track events (drift) anywhere from .9 bar to 1.5 bar depending what i want it at for the day last few events have been 1.4 bar haha it works great 9:1 compression rebuilt engine. __________________ Aaron Pink GodziRa www.geocities.com/pink_godzira

09-15-2007, 04:06 PM	#3
Cone Leaky Injector Join Date: Jan 2006 Location: Portland, OR Posts: 85 Trader Rating: (0) Feedback Score: 0 reviews	I did a few searches, and it seems like cometic is allright. It seems though that people like the Apexi though a lot, but it's twice as much.

01-05-2008, 02:44 PM	#8
240SX2high2aim Leaky Injector Join Date: Aug 2007 Location: SoCal Age: 64 Posts: 72 Trader Rating: (0) Feedback Score: 0 reviews	Hey man I dont get what is the difference between different head gasket sizes. What is could if you want more boost bigger or smaller plz explain.

01-05-2008, 03:58 PM	#12
Doluck Zilvia Member Join Date: Nov 2005 Location: Jacksonville, Fl. Age: 44 Posts: 182 Trader Rating: (0) Feedback Score: 0 reviews	I love the apexi, it has done me way better than cometics.... (22psi daily on a .08x86mm) I would stay with .08 or 1.mm x86mm unless your looking for 600+hp. Problem with cometic is they sell 1 kinda gasket for sr20 its a 88.5mm bore for a fwd, its has about 17 diffrent part numbers for the diffrent car. If you call them they will tell you its the same gasket and it wont hurt anything. That BS.. the fwd is alittle diff. from the rwd. It can be used tho.. Anyway.. other issues are no fire ring, oil holes that dont line up. because the hg being to large pitting, erosion from detonation happens to the top of the cylinder walls, i have even see the walls cave in.. you can find about 1000000 threads on all of these issues on FA by Mazworx, and many others that mave built more motors than me.. ive aonly done about 8

01-08-2008, 05:26 PM	#13
smelly240 Nissanaholic! Join Date: Oct 2006 Location: Philaburbia Age: 47 Posts: 2,137 Trader Rating: (4) Feedback Score: 4 reviews	riiight... except they have in stock at multiple places 86.5 mm bore gaskets from cometic for s1X. I have never had a problem with my 86.5mm bore cometic - which apparently must not exist (i got mine the day after i ordered it from extreme psi btw) all my oil holes lined up perfect and the everything to date is fine. for the thread bumper guy - thicker HG lowers compression so u can safely increase boost... u want the HG bore within .5 of ur bore size in most cases __________________ HREs on a S13 - check, 6262 - check, Girlfriend.... - nope

01-08-2008, 06:21 PM	#14
PoorMans180SX Zilvia.net Advertiser Join Date: Nov 2005 Location: Michigan Age: 37 Posts: 5,616 Trader Rating: (16) Rides Gallery: PoorMans180SX Feedback Score: 16 reviews	Don't buy a thicker head gasket. It's dumb. The proper way to lower/raise compression is with different pistons. There is no need to lower your compression on a stock SR20DET as it's already relatively low at 8.5:1. As you can see Dousan runs a 9:1 motor. Thicker headgaskets decrease quench area, making the air/fuel charge less homogeneous and upsetting combustion smoothness. Lower compression also decreases off-boost torque and throttle response. Spend your money on a good stock-thickness headgasket and get a good tune. Your engine will thank you. __________________ Build: http://zilvia.net/f/showthread.php?t=643065 Friends don't let friends buy knock-offs.

01-08-2008, 08:18 PM	#15
Doluck Zilvia Member Join Date: Nov 2005 Location: Jacksonville, Fl. Age: 44 Posts: 182 Trader Rating: (0) Feedback Score: 0 reviews	Its not 86.5.. if you messure it you will find its 88.5mm

01-09-2008, 04:23 AM	#16
smelly240 Nissanaholic! Join Date: Oct 2006 Location: Philaburbia Age: 47 Posts: 2,137 Trader Rating: (4) Feedback Score: 4 reviews	screw u ass - its 86.5 - here notice you can pick the bore size. OMG no way!??! stop looking at threads mazworks posted in 05 and get with it... it also makes the quench area bigger... the thing that upsets it is the oversized HG bore. Which as i just posted - isnt a problem (since cometic does make the smaller bore gasket - despite what the guys on FA thought*) __________________ HREs on a S13 - check, 6262 - check, Girlfriend.... - nope

01-09-2008, 09:00 AM	#17
Hooorahh! Zilvia FREAK! Join Date: Jan 2007 Location: california Age: 45 Posts: 1,195 Trader Rating: (0) Rides Gallery: Hooorahh! Feedback Score: 0 reviews	i would honestly go with a tomei / apexi whatever 1.2mm and call it a day ... its just the safest way to go ... u might say u want 15 psi now but then later u might want 18-20 so just to be safe and not have to spend more money in the long run

01-09-2008, 09:27 AM	#18
tr_racing Leaky Injector Join Date: Feb 2003 Location: Quebec Age: 42 Posts: 64 Trader Rating: (0) Feedback Score: 0 reviews	I just ordered a ApexI 0.8mm x 86mm with ARP headbolt for my S15 SR20. Kevin..

01-09-2008, 01:48 PM	#19
Koopa Troopa Post Whore! Join Date: Sep 2006 Location: 北谷著, 沖縄県、日本 Posts: 2,565 Trader Rating: (3) Feedback Score: 3 reviews	I have a Tomei 1.2 because my head has been decked 2mil and it's been decked before I got it too... Bigger head gasket to keep my pistons from slappin my valves.. __________________ Buy my Stillway shifter!