Hi Guys I have an 04 350z Roadster with the JWT TT kit. I'm in the middle of building my engine and have a question about head gaskets. My hp goal is at or just500rwh and I figure about 18-20 psi max. For the people with FI what head gaskets are your running? I have purchased the Cometic headgasket set but I have some people to use the stock one as they have had problems with the cometic gaskets leaking. Any thoughts you could share would be apreciated.

Thanks Mike

 

i've always thought that the HKS head gastket was pretty much de rigeur for people who were building their motors.

 

IMO HKS because of the o-rings. To date I have yet to see one HKS gasket fail. We have on the other hand seen Cometic HG's fail, but to be fair many factors could have contributed to those that did fail-and having the HKS in some scenarios would have "saved" the motor....

 

Hks Ftw!!!!!!!!!!

 

Personally, I went with Cosworth. But HKS is good as well.

 

sometimes, losing a headgasket can save the motor. headlift is more a factor of detonation than too much boost. Detonation can jack cylinder pressures much higher than boost will! It is better to lose a headgasket than to lose a piston/cylinder.

I am not doubting the effectiveness of the HKS gasket, but I think the cometic may have gotten an undeserved bad reputation. all the big bore VQs use the Cometics(unless people are modding other gaskets). cometic has 100mm and 101.5 mm bore HGs for the VQ35.

also, the HKS gasket isn't an "o-ring" Headgasket. it has a "stopper" ring. traditional "o-ring" headgaskets require a receiver groove to be machined into either the head or the block to accomodate the special o-ring headgaskets.

............for what it's worth, I'll probably end up using the HKS gasket.

 

buy my nismo headgaskets! .7m

https://my350z.com/forum/showthread.php?t=315710

 

arent cometic just the same as the oe headgasket with difference thickness? I rather pay the extra $$$ for the HKS than risk headlift in the future.

 

i don't know how many people are running cosworth, i have no doubt that it is a quality product, but it seems to me that a very large number of built VQ's are running the HKS gaskets

 

I understand this. But just because a majority of the people use something doesn't always mean it's the best or the only comparable option for upgrade. Just giving him another option.

 

+1

 

HKS gets my vote. Cosworth is coming out with their own line of stopper ring style gaskets. Saw some samples at SEMA, and they look very promising. This time, they aren't rebranded Cometic. Time will tell if they hold up.

 

the hks is hands down the most reliable. atleast it is on this forum. but for your hp goals and boost levels a cometic will do fine. only rarely have people had issues with a cometic or cosworth...and when they do its due to the fact of over punching their car. or just because of bad installation problems.

but if you want to be safe....and have that safe mindset about your engine then just get the hks...you can get an hks for as low as 325 if you know where to look...a cometic or cosworth is still going to run you 200 so for an additional 125 and the ease of mind id go with the hks.

 

a mde this a while ago, a comparison between stock and hks; http://cj-motorsports.com/headgaskets1.htm

not sure if anyone has seen it lately

 

It was the reason why I went with HKS. Great write up and analysis.

 

We have run stock (780rwhp), Cosworth's old style (1000rwhp), and Cometic (650rwhp) and have not had any problems yet...knock on wood.

 

no one has experience with the nismo head gaskets?

 

Stock for me and holding strong.