Cometic head gaskets?

I'e been reading on build threads lately about cometics head gaskets. And people are saying not to use them?

I purchased a kit from CZP and it came with the head gasket. We've put the heads on already, the block was shaved and honed, dipped. And the heads were also shaved etc. Does this mean my surfaces are right? When installing it my housemate (the mechanic) sprayed blue stuff on the gaskets saying it will make it seal that little bit better..

I did a search and not much infomation came up on the cometic gaskets.

Does any one use them and not have problems? or having problems?

 

I'll be looking at one of the full gasket kits from czp in the near future. Did you go for the one that mentions metal head gaskets?

Personally I wouldn't use them. I've used different brand metal gaskets in the past and was lucky to get 10k out of them before having problems. That's on a freshly built engine, decked heads, etc and using that Blue head gasket spray.
But this was close to 10 years ago and it's safe to say head gaskets have improved a lot over that time.

Since then I've only used OEM gaskets and had no trouble. Even at over 30psi boost!
I was reading about a 1900HP built 2JZ a few weeks ago. Even that was running a OEM head gasket!!
Just my 2cents worth.

 

I like Cometic headgaskets. 95% failure rate is utter shit. I have done probably 10 VG's with cometic gaskets . no failures

 

I will only run greddy or Tomei metals .
I ran greddy's on last engine.

Never had much luck with stock headgaskets..(rev limiter)

Cometic are probably fine but have seen /read more failures than the above choices .

 

The biggest key in using any MLS style gasket is to ensure the deck surfaces are straight and flat as well as they must have a CBN style finish (mirror) in order for the gasket to be used properly. Most don't get this done which at times give those an issue. DO NOT spray copper/blue coating on the gaskets as all of the MLS gaskets have the rubberized coating on them that is standard from the manufacture.

ALL MLS gaskets can be reused up to 3 times before discarding.

hope that helps

 

have a search on tt.net if you need evidence. not 2 mention the recent failures of rob260s on a freshly built motor machined 2 perfection, not just a home DIY job not 2 mention there is a reason why specialty Z wont use them and kye from IPP in the states wont touch them . and seb is running a 9 second Z :br:

why risk it. cometic fail !! thats been proven

 

I didn't say they were good I just said the issues I've seen with individuals using them. I personally use Tomei in any MLS gasket I use unless the customer sends me Cometic. I warn them but they want to proceed. All I can do is assemble the way I know how. To date I havent had any fail but thats not saying that one will. A lot of issues do lie in the assembly though.

For these reasons that some have had failures in the HG dept I've contracted a company to make my own MLS gasket similar to Tomei which I hope to bring to market this year. Infinite bore size and thicknesses.

 

Nothing found on any internet forum is evidence! A lot of it is utter BS being typed by kids still at school pretending to be big shots.

My experience has seen one engine build with Cometic head gaskets require a re torque then no trouble at all (I did not build the engine), I have built 4 or 5 engines with Cometics with zero issues.

Have seen one engine built with composite gaskets that the engine builder swore by, lasted as far as the tune session on the dyno & blew at 10PSI boost.

I agree with Tech@EPR a lot of it comes down to machining & assembly, ALWAYS torque the heads down as per the instructions then allow to sit as long as possible & re torque, you will find they tend to settle & when you re torque them they will take as much as another 1/8th of a turn depending on various factors.

The ones that have failed on TT.net:
Head bolts or studs?
New or re used?
Correct lube on threads?
Cooling system bled properly so no air lock on start up?
Calibrated torque wrench or retired grandfathers one he got when he was an apprentice & has dropped twenty times but never re calibrated?
Gasket surfaces cleaned with what? - (turps will leave a residue)
Surface finish? sure machined but to what spec & with a grinding wheel or fly cutter?

Sooooooooo many factors & you can bet 99% of posters will NEVER admit when they screwed up.

How many posts have you seen where someone blames a product for being mud then comes back later & posts "actually the product failed because I screwed up the install"? nah not many if any.

 

There have been guys filling the system up with coolant prior to startup too , then wonder why they have problems

 

Thanks for all your advise guys.

Decided to leave it in there, shown all the posts to my mechanic mate and he has said if it lets go he'll personally pull the motor back out for me and replace the gaskets.

Guessing there are lots of people out there that use them, you only hear from the ones that fail..