cometic head gaskets???

D

duramaxcummins

Chevy Cummins
Joined
May 18, 2008
Messages
93
are cometic head gaskets any good or are they basically a waste of time? any idea on what kind of boost they can handle with a studded head? thoughts would be appriciated.
 
there a waste of time. i had an mls one that lasted 3 months. i was driving down the interstate and it blew in 4 different places. this was 2 yrs ago. 12mm studs, 45psi of boost was the max i saw with it
 
Never used them but heard they suck. Had a buddy insist on running one and it blew in just a couple weeks. Barely a 400 hp truck. He gave another one a try and same thing. So I would say no go on them.
 
They work ONLY if both the head and the block are perfectly flat. Just like the common rails come from the factory.
 
BigB82789 said:
They work ONLY if both the head and the block are perfectly flat. Just like the common rails come from the factory.
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I agree.
IMO, the head and block both need to be decked in order to run any kind of MLS gasket.
An MLS gasket is less tolerable to imperfections on the surface it is mating to than a regular gasket is.
 
BigB82789 said:
They work ONLY if both the head and the block are perfectly flat. Just like the common rails come from the factory.
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They still blow when both the head and block are surfaced.
Many people on here tried them and not one has lasted.
 
Forrest Nearing said:
you realize that all Cummins heads and blocks come perfectly flat from the factory, right? :confused:

the Cometics are JUNK!!!!!!
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Take a 100,000 mile or more head and block like alot of these guys have and check its flatness. It's not perfectly flat...
 
haha well i guess im not wasting my time or money on one of them than. so just o ring it and be done with it?
 
BigB82789 said:
Take a 100,000 mile or more head and block like alot of these guys have and check its flatness. It's not perfectly flat...
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very true...

now, take one of those engines and do the standard "mill the head flat, o-ring it, and stud it" vs. "mill the head flat, and wave the cometic unicorn horn over it" and see which one actually holds
 
What about having a Cometic gasket cut for firerings and going that route. Just wanted to ask cause I have a friend that is doing this. I tryed to talk him out of it, but he wanted it done.
 
Timebomb said:
What about having a Cometic gasket cut for firerings and going that route. Just wanted to ask cause I have a friend that is doing this. I tryed to talk him out of it, but he wanted it done.
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I talked to Brad at Schieds about doing this for one of my deals. He said that they had a custom MLS gasket made with no fire ring built in and the are putting the .105 firerings in with it. It required 14mm studs to properly compress the rings. He said so far they were holding good in there test trucks but they didnt have enough time for a longevity test. So the only thing different is the gasket? I said why change something that we know works well like the Cummins factory gasket. Sounds like im glad i didnt try it. Tim
 
ILLINOISRAM said:
I talked to Brad at Schieds about doing this for one of my deals. He said that they had a custom MLS gasket made with no fire ring built in and the are putting the .105 firerings in with it. It required 14mm studs to properly compress the rings. He said so far they were holding good in there test trucks but they didnt have enough time for a longevity test. So the only thing different is the gasket? I said why change something that we know works well like the Cummins factory gasket. Sounds like im glad i didnt try it. Tim
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Yep that's what he's doing. Guess time will tell.
 
I was one of the lucky ones to try the cometic too. Got a whopping 300 miles out of it before it blew!:bang
 
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