cometic headgasket or HR headgasket
cometic headgasket or HR headgasket
i planing a 450whp Dynodynamics build and i was wondering is the cometic head gasket good for the job??? i know ive searched but everyone just says HKS. but thats $300. i dont want a 700whp car or a 18 psi TT 350z. my goals are only a measly 450 dynodynamics (built bottem end). PLAIN AND SIMPLE. so i dont want to overbuild. will the cometic suffice???? advice greatly appreciated.
edit title to DE headgasket
edit title to DE headgasket
Last edited by De La Money; Oct 15, 2009 at 10:26 AM.
AFAIk Joe is the only "proven" case for HR HG's. He had headlift issues and that was that but I wouldnt go around saying an HR gasket would perform as well or stand up better than even a Cometic HG. Perhaps in regards to cooling but its too soon to say IMO, more people need to prove these things.
For something as crucial as a HG, $300 is nothing to worry about (especially considering your SN LOL), if it is, you shouldnt be building IMO.
For something as crucial as a HG, $300 is nothing to worry about (especially considering your SN LOL), if it is, you shouldnt be building IMO.
Last edited by Alberto; Oct 15, 2009 at 11:00 AM.
GTM and JWT both have been using HR headgaskets for a while now. I personally spoke with both Jim and Sam regarding this issue, and they both recommend the HR headgaskets over the Cometic and stock DE headgaskets.
I know some people have issues with these companies, but both of them have been at this for a long time.
Of course, the HKS head gasket is definitely the most proven at this point, and I don't think anyone will go wrong using that head gasket.
For my build, I am still debating between the HKS and HR head gaskets, and it has nothing to do with cost (even though the HKS is around $360 and the HR is around $70). The issue I am looking at is the improved coolent flow path of the HR head gasket. Sam is using the HR head gasket on the 1000 whp (projected hp) Autobahn build, so I am going to closely monitor how that progresses before deciding.
I know some people have issues with these companies, but both of them have been at this for a long time.
Of course, the HKS head gasket is definitely the most proven at this point, and I don't think anyone will go wrong using that head gasket.
For my build, I am still debating between the HKS and HR head gaskets, and it has nothing to do with cost (even though the HKS is around $360 and the HR is around $70). The issue I am looking at is the improved coolent flow path of the HR head gasket. Sam is using the HR head gasket on the 1000 whp (projected hp) Autobahn build, so I am going to closely monitor how that progresses before deciding.
Last edited by ttg35fort; Oct 15, 2009 at 11:12 AM.
Dont get me started on inflated JWT dyno numbers or GTM
Believe who you want...IMO its not proven, I know the companies mentalities when providing dyno numbers to the public then knowing how the customers/shops really treat the cars.
Id personally trust shops like Intense and SP before GTM when it comes to "this head gasket WILL HOLD XXX power"
Drag racing with 900+whp AND spinning motors to 9000rpm is serious business, if you dont think it is, ask your shop why they havent done it!
1000+whp dynos and road racing at 500whp is blah to me...
Believe who you want...IMO its not proven, I know the companies mentalities when providing dyno numbers to the public then knowing how the customers/shops really treat the cars.
Id personally trust shops like Intense and SP before GTM when it comes to "this head gasket WILL HOLD XXX power"
Drag racing with 900+whp AND spinning motors to 9000rpm is serious business, if you dont think it is, ask your shop why they havent done it!
1000+whp dynos and road racing at 500whp is blah to me...
Last edited by Alberto; Oct 15, 2009 at 11:17 AM.
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HR gaskets here on my DE build and no headlift at this point (granted not a lot of miles at this point 1500ish). When I discussed this with Joe prior to starting my build he said the HR gaskets were solid. The post I read about his headlift (I can't find it since) clearly related the headlift issue to the TTY headstuds, not the gaskets, and that failure happened at ~17psi and ~650whp.
OP, remember that you must make this decision prior to machining the block because you ned to cut a cooling passage to match the HR gaskets IIRC.
Just my two cents on this topic. HKS is solid nd works....period. HR is less proven, but very inexpensive. Cometic is good/bad depending on what person or shop you ask. In the grand scheme of things $300 is a small amount, but the small amounts are what add up to the big dollars to go F/I.
OP, remember that you must make this decision prior to machining the block because you ned to cut a cooling passage to match the HR gaskets IIRC.
Just my two cents on this topic. HKS is solid nd works....period. HR is less proven, but very inexpensive. Cometic is good/bad depending on what person or shop you ask. In the grand scheme of things $300 is a small amount, but the small amounts are what add up to the big dollars to go F/I.
HR gaskets here on my DE build and no headlift at this point (granted not a lot of miles at this point 1500ish). When I discussed this with Joe prior to starting my build he said the HR gaskets were solid. The post I read about his headlift (I can't find it since) clearly related the headlift issue to the TTY headstuds, not the gaskets, and that failure happened at ~17psi and ~650whp.
OP, remember that you must make this decision prior to machining the block because you ned to cut a cooling passage to match the HR gaskets IIRC.
Just my two cents on this topic. HKS is solid nd works....period. HR is less proven, but very inexpensive. Cometic is good/bad depending on what person or shop you ask. In the grand scheme of things $300 is a small amount, but the small amounts are what add up to the big dollars to go F/I.
OP, remember that you must make this decision prior to machining the block because you ned to cut a cooling passage to match the HR gaskets IIRC.
Just my two cents on this topic. HKS is solid nd works....period. HR is less proven, but very inexpensive. Cometic is good/bad depending on what person or shop you ask. In the grand scheme of things $300 is a small amount, but the small amounts are what add up to the big dollars to go F/I.
If you search JWT's website, they have a pdf showing the differences between the 3 generations of head gaskets for the VQ35 motors (i.e., DE, rev-up, and HR head gaskets). You should take a look at that.
I have seen some people push the DE headgaskets to the mid 400 whp range on stock motors. You might want to do some research to see how they held up. I can't say I have heard of head lift at that level of hp, but then again I never was really interested in running a DE head gasket, so I really didn't pay attention.
If you have not yet built the motor, you might look at going with something a little more stout just for added safety. The HR head gaskets fit the DE motor and cost about the same as the DE head gakets. The HKS headgaskets are the most proven head gaskets for our platform, but they are north of $300. If you really want to run the DE head gasket, then give it a try and report back to the forum to let us know how it worked out.
I have seen some people push the DE headgaskets to the mid 400 whp range on stock motors. You might want to do some research to see how they held up. I can't say I have heard of head lift at that level of hp, but then again I never was really interested in running a DE head gasket, so I really didn't pay attention.
If you have not yet built the motor, you might look at going with something a little more stout just for added safety. The HR head gaskets fit the DE motor and cost about the same as the DE head gakets. The HKS headgaskets are the most proven head gaskets for our platform, but they are north of $300. If you really want to run the DE head gasket, then give it a try and report back to the forum to let us know how it worked out.
Last edited by ttg35fort; Oct 15, 2009 at 01:59 PM.
If you search JWT's website, they have a pdf showing the differences between the 3 generations of headgaskets for the VQ35 motors. You should take a look at that.
I have seen some people push the DE headgaskets to the mid 400 whp range on stock motors. You might want to do some research to see how they held up. If you have not yet built the motor, you might look at going with something a little more stout just for added safety. The HR head gaskets fit the DE motor and cost about the same as the DE head gakets. The HKS headgaskets are the most proven head gaskets for our platform, but they are north of $300.
I have seen some people push the DE headgaskets to the mid 400 whp range on stock motors. You might want to do some research to see how they held up. If you have not yet built the motor, you might look at going with something a little more stout just for added safety. The HR head gaskets fit the DE motor and cost about the same as the DE head gakets. The HKS headgaskets are the most proven head gaskets for our platform, but they are north of $300.
It shouldn't cost much. You're going to need the block machined anyway to bore and hoan the cylinders, just have them do the cooling mod at the same time. GTM is not charging me anything for this on my block. The JWT document I mentioned shows where to notch the openings. Here is a link:
http://www.jimwolftechnology.com/wol...HEAD_BOLTS.pdf
http://www.jimwolftechnology.com/wol...HEAD_BOLTS.pdf
We've done a mix of HR gaskets and HKS gaskets. Still prefer HKS, but no issues yet with HR. Honestly, at 450whp you aren't going to have a headgasket problem with either one.
Just make sure to use ARP L19 headstuds and trq to 95 ft/lbs with moly. Best of luck.
Just make sure to use ARP L19 headstuds and trq to 95 ft/lbs with moly. Best of luck.
FYI, it appears there has been yet another Cometic head gasketed motor experiencing head lift, this time on Sylvan Lake's car. It could be the sleeves or the HG, I don't think he knows at this point. For those that are still considering Cometic head gaskets, proceed with caution. Sylvan Lake did mention that Cometic has a new HG design coming out, maybe that one will be better.
Last edited by ttg35fort; Oct 22, 2009 at 08:34 AM.
they are 225 bucks vs the 369 I see the HKS gaskets for.
The car is holding up well. APS TT stetup; He sees the car spike to around 17 and settle in to around 15. He has about 5K miles on the build. We fiinished it up in '08, He went to the track last month and made 22 passes and all seems to be fine
I haven't seen the cometic, but I saw pics of both when we were ordering parts and they looked different. The cosworth gaskets we received from sharif looked very similar to the HKS gaskets I put in my motor.... and are even described as having the stopper ring like the HKS gaskets on sharif's site.
they are 225 bucks vs the 369 I see the HKS gaskets for.
The car is holding up well. APS TT stetup; He sees the car spike to around 17 and settle in to around 15. He has about 5K miles on the build. We fiinished it up in '08, He went to the track last month and made 22 passes and all seems to be fine
they are 225 bucks vs the 369 I see the HKS gaskets for.
The car is holding up well. APS TT stetup; He sees the car spike to around 17 and settle in to around 15. He has about 5K miles on the build. We fiinished it up in '08, He went to the track last month and made 22 passes and all seems to be fine
(I think this is when Japtrix stopped using Cometic H/G's on VQ motors.)