Cometic Head Gasket success? horror stories? what ya got...post up!

[Carl H]

Well after scratching my head for several weeks now trying to figure out WHY my car is acting the way it has been ever since i got back from Fl with the Jag I have come to the conclusion that I suspect the head gasket is blown.car starts, runs, drives great but idles like poo and recently I have discovered has been eating coolant (but with no sign of coolant in the exhaust!).Loss of coolant as well as poor idle vaccum (but great decel vaccum, and unchanged performance) leads me to believe that perhaps the 'sleazebay special' gasket i fitted some 50-60k odd miles ago has finally given up the ghost even with arp head studs...or perhaps it was just my antics running the car on 22psi finally catching up to it.

the question posed is this:a) who has used a cometic gasket?b) has it leaked and caused issues?c) if any issues what and how were they rectified?andd) would you reccomend fitting one to an rb engine again?

I have had less than great success fitting cometic gaskets to nissan 4 cylinders with them leading to either a) severe aghervation, b)removing and refitting a stock hg, or c) fitting some kind of jdm gasket.i'm curious to see what kind of results the rb guys have gotten as it seems the jz crowed seems to have good luck with them...but i could be wrong!

[jdmser]

The only time I've personally run a Cometic head gasket is on the 650cc in my Kawasaki X2 and it's held up for years. I have heard of a lot a domestic guys having great success with Cometic head gaskets and boosted application, my friend's 383 71 Chevelle w/ D1SC Procharger for example. It seems to me that preparation is the key. The head and the block must be milled for it to seal. It's not a slap-n-go gasket.

[DrifterProdigy85]

Whats your compression say carl? Wont a blown headgasket show low compression between the two cylinders that are leaking or where it leaks into the coolant passages?

[kouki-gymkhana]

I don't have any experience with Cometic HGs aside from the fact that when I tore my engine down after I blew my HG, I'm pretty sure it was a 3-layer metal Cometic gasket that failed.

I'm waiting for Darius to chime in...I *think* he might have some strong opinions on this matter...

[USMCgetsome]

from all the years of reading cometic head gasket leaks and failures a few instances popped up. Preparation is the key and the use of COPPER Spray to help it seal better are your goals. good luck.

[DrifterProdigy85]

I see alot of guys use Cometic on there SR's and they have issues. Could be from not prepping though. Personally i like Apexi. Its got a crushable ring around each cylinder giving a very good seal.

[S14-NEO]

i had a cometic on my SR before i went RB and i have to say i thought the gasket was a complete pile of crap. i got into a heated dicussion with a few people who completely defended the cometic gaskets quality until i told them to compare with a japanese version of the same gasket..when that was done there was no comparison.. without a doubt i would go at the very least with an Apexi head gasket or if you have the coin for it the best out there would be a tomei.

[Darius]

Ahhh this thread brings back repressed memories.

I completely agree that preparation is key on any metal head gasket (MHG). HOWEVER, the smoothness recommended by Cometic was something that could not be achieved by simply decking the block and head. A near mirror finish is required to get the 50A (?) smoothness, which takes additional polishing. Ludicrous when you can get a gasket for the same price that doesn't require that level of finish.

On my first go around, I only decked the head and cleaned the block up the best I could with extremely fine grit sand paper and it leaked upon startup. My bad! The second go around, I had both surfaces milled and the gasket still seeped. Cometic's bad! I didn't see evidence of any coolant in the oil, but it definitely seeped down the side of the block. I am on the third gasket and this one has sealed, for now. I don't want to jinx it.

There are other gaskets out there that are more forgiving. Cosworth, HKS, etc. The problem with the Cometic gasket is that they use Viton to coat the metal layers. Viton is a very smooth, slick material that has higher temp resistance than EPDM, but it is an inherently troublesome gasket material. This is not only for engine applications, but for large industrial air supply applications too. Contractors always complain when we specify them install Viton gaskets in air piping because they always have to go back and reseat the gaskets.

I'm not a huge fan of copper spray since it is a bit of a band-aid fix IMHO.

If I ever have to pull the head, I'm reinstalling a Cosworth gasket.

[cdorhout]

Cosworth FTW I've installed two new Cosworth head gaskets and even re-installed one after using it once before and no leaks ever.

[gawdzilla]

i'm running a cometic, probably 20k of on it in the past 5 years. car is hardly street driven and mostly on the track. the gasket has not given me problems and i did not spray it. head and block were finished when i built the motor, and both were prepped super clean at assembly.

given an HG is not something you want to do again, i'd probably spring for something a little "better" at this point. probably cosworth. when my aftermarket parts were being pieced together in 03-04'ish there were hardly any options... that's probably why you ended up with a cometic at the time too, carl. it's been good to be so far though.. *knock on wood*

also... did you re-torque your studs?

[Carl H]

i actually used some generic hg kit i got off ebay for my rebuild...didnt look nearly as beast as the stock oem gasket.like i said i got 50-60kmi out of it before it gave me issues...after all the feedback my mind on cometic gear hasnt changed and i'll most likely source a STOCK oem nissan gasket and go from there.

[lexrob]

Im running a cometic without a resurface. Only got to drive it for two weeks until wiring error on my part. I've had no signs of problems yet hope it holds! I could not find an oem in the states so..... arp 85ft. ((no retorque))

The retorque part is def. a touchy subject.

[lexrob]

I did some research on it and cometic states no retorque is required! Clean DRY surface (no copper spray) -heard both ways on it tho

There are a few people out there runnin one without a resurface. Some people say to retorque anyways. Some say retorque IF it leaks.

OEM is the ways to go if your not going over like 400 so i've heard "if you can get/find one"

[240z4u]

I did some research on it and cometic states no retorque is required! Clean DRY surface (no copper spray) -heard both ways on it tho

There are a few people out there runnin one without a resurface. Some people say to retorque anyways. Some say retorque IF it leaks.

OEM is the ways to go if your not going over like 400 so i've heard "if you can get/find one"

You can make well over 400hp without any problems with a stock headgasket.

Why not run stock gasket carl?

I don't understand the appeal of a mhg for an RB. it seems to me that ringlands get destroyed well before headgaskets do. If you have a built lower end, then that is different I guess.. however I still don't think that 99% of MHG users should have bothered.

Evan

[StricNyne]

i have no proof of this, but idk where i saw or heard this but i heard that cometic rb gaskets suck, so i ponied up the money for a tomei, but like i said idk where i heard it (4 years ago) or form who

[Carl H]

well like i stated in the original post the engine was put back together with a stock style composite gasket and it has held up for 50-60kmi now...the gasket looked much 'weaker' than the stock gasket that was removed from the block...infact stock gasket looked fresh as can be dispite being overheated badly 4 different times.I'll just go with another oem nissan gasket and call it a day...just was curious about the cometic.

[240z4u]

well like i stated in the original post the engine was put back together with a stock style composite gasket and it has held up for 50-60kmi now...the gasket looked much 'weaker' than the stock gasket that was removed from the block...infact stock gasket looked fresh as can be dispite being overheated badly 4 different times.I'll just go with another oem nissan gasket and call it a day...just was curious about the cometic.

Carl, just to clarify.. I wasn't dumping on you. Just thinking outloud.

Evan

[lexrob]

Just curious where can you get an oem head gasket right now?

Why are dsm guys all about mhg's for reliability, where rb's oems fine.

Carl did you get my message? sorry its urgent.

[TimeAttackTheory]

I see alot of guys use Cometic on there SR's and they have issues. Could be from not prepping though. Personally i like Apexi. Its got a crushable ring around each cylinder giving a very good seal.

The cometic head gasket has the same crushable ring. Ususally when people have problems with them is when they run a cometic h.g on an engine that came stock with a single layer gasket. for best seal id resurface the head and deck with the appropiate finish for mls head gaskets as sr's do not come with this finish from the factory. i'd also o ring the block copper spray isnt a bad idea but not necessary as the grey coating on the outside of the gasket serves the same purpose.

[rb25det250sx]

Just curious where can you get an oem head gasket right now?

Why are dsm guys all about mhg's for reliability, where rb's oems fine.

Carl did you get my message? sorry its urgent.

lol does the letters DSM mean anything to you... a DSM head gasket will go out at just the thought of over heatin the motor, or boost over like 16psi.

at least mine went out a 16psi. and never overheated. not once. there fragile motors

[flatrate]

i have a cometic gasket in my honda i run 30psi thru it reguarly on pump and meth it makes well over 600whp and i havent had an issue until just recently which was my fault.. i never retqed the head studs and they were loose...

I havent pulled the head off yet but i am experiencing low idle vacuum, and i get bubbles out of the radiator during a leakdown test... so obviously somethings up haha... i still drive it and boost the s*** out of it and its never overheated

I have heard people on both sides of the fence but i have had good luck with them so far... my block and head were both milled prior to installation and my paticular engine comes MLS from the factory

I also have a cometic on my Rb25 but i have yet to run it... both surfaces were milled prior to install

[boosted98gst]

thats all a myth I made over 600 hp on a stock oem mitsu headgasket. I remember back in 01-02 I had an issue with cosmetic with a headgasket on my dsm, I will never again use that company.

[ItzGenX]

I ran a cometic as my first gasket for my sr race motor, never again. The head and blocked were milled and prepped to literally almost a mirror. The motor upon the first 10 mins of idling started puking oil at the rear of the head all over the transmission. So I had to pull the head and tried using my spare cometic head gasket (ordered 2 at the time) with copper spray. This time it ran for about 40 minutes total (mostly idling) and began seeping out oil slowly this time right under the #1 intake runner. I got fed up and custom ordered a 90mm apex'i gasket from a friend stationed in japan at the time to pull strings for me (90mm bore sr22det btw). The apex'i gasket LOOKED so much better, as it had a fire ring that gets squished around the top of the cylinder to ensure a nice tight seal. The oil ports on the gasket had a rubbery coating around them too. This gasket has NO leaks and that was about 5 years ago. Still to this day puts down 509rwhp on 93 octane revving to 9.5k rpm with not so much as a seep. I learned my lesson there with cometics and parts in general. You buy cheap, you buy twice.

[Fibre guy]

You guys are scaring me... I have a cometic hg.

[flatrate]

i will be running oem honda gasket this time around, even though i didnt have an issue with cometic

the only reason im using cometic on the RB is because its the only MLS gasket resonably priced... i hate those composite style gaskets..such a PITA

[rb25det250sx]

thats all a myth I made over 600 hp on a stock oem mitsu headgasket. I remember back in 01-02 I had an issue with cosmetic with a headgasket on my dsm, I will never again use that company.

i somehow dont believe you, seeing how 3 of the fastest DSMs in the U.S and a 1000hp evo are from (my town) Iowa. and there is no way it was stock. but OEM maybe.

[boosted98gst]

First of all im not going to get in contest on benchracing this and that..... mitsu does make an oem gasket for high hp apps its not the stock oem gasket from the factory durrrr lol second the fastest dsm's are in ohio http://www.dsmtimes.com sheps are is over 1400 hp http://www.shepracing.com. and the fastest evo's are http://www.burshurracing.com in wakeman ohio also. The top 7 fastest evo/dsm this year are all from ohio.........you can check with this also at http://www.dsmtimes.com

[boosted98gst]

Here you go the 12 fastest dsm's in the whole world 10 of them out of central ohio.

#1 Brent Rau 6.970 198.00 0.000 0.00 0.000 81 mm borg warner No ACT, osofastracing.com NABR#2 Bob Niemczyk 7.610 171.77 4.799 142.39 1.096 GT4202 No NABR#3 Albert Lioe-a-tjam 7.660 175.04 4.880 142.47 1.118 GT45R Yes Buschur Racing #4 John Shepherd 7.700 191.32 5.104 148.07 1.296 FP GT42R Yes Shepracing.com, FP, ACT, Polk, AMS, Busc NABR#5 Ryan Garcia 7.797 174.41 4.964 140.66 1.159 T 72P Yes SKF/ United Auto & Performance Ltd. #6 David Buschur 7.810 174.46 5.010 141.02 1.140 T67 P trim Yes Buschur Racing #7 Nick Zervos 7.943 176.96 5.200 138.97 1.185 GT42R No APC, Castrol, Haltech, ARE #8 PHIL DAVIDSON 8.074 167.21 5.146 134.65 1.161 67MM Yes First Impressions Collision #9 Andre Simon 8.230 179.50 5.460 139.80 1.419 T51R SPL No TSW/Speedtech #10 Chris Carey 8.410 161.69 5.387 130.57 1.285 BW S380 Yes Modern Automotive Performance #11 Kevin Kwiatkowski 8.424 166.52 5.499 136.17 1.346 Borg Warner 74mm No Precision Industries, Wiseco, FP, Monkey NABR#12 Serge Turcotte 8.471 169.02 5.576 132.48 1.406 GT42R No F. Villeneuve/Camo/Quebec Perf./Magnus M

[boosted98gst]

here is my run @ norwak

http://www.youtube.com/watch?v=nKIRstpY3sA

white 1g. Too bad im not on that top 3 last I checked I was like 123rd in the nation, but im ok with a 9 second street car.

[boosted98gst]

And like I said I was running 601 awhp 8 years ago this 2009

http://www.youtube.com/watch?v=G84qbWfcQB8