Cometic mls failed!

M

mhuggler

One piece at a time
Joined
Sep 20, 2007
Messages
1,526
I replaced my head gasket with the mls no more than 300mi. ago and it just blew again!*bdh* I can't even think of any reason it could possibly blow again. I took my time and made sure everything was perfect. I surfaced the head plenty smooth enough for a mls gasket and installed it with a new set of ARP studs.:( Any ideas? Does Cometic offer any kind of warranty with their gaskets? While I was at it I put a set of mach 5's in(which are awesome btw), so now I'm pretty much beyond broke! Has anyone else had any problem with the mls? Should I try a marine gasket? TIA.
 
what where the boost#'s and egts before it blew i am intrested in why and what cause i am looking at getting one of these
 
cahammer said:
what where the boost#'s and egts before it blew i am intrested in why and what cause i am looking at getting one of these
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I was just going to work cruising down the highway. Every time the boost came up I could hear compression blowing through the gasket.
 
Has anyone blew the super dooper cometic. I don't know what it is called.It is like their 'replacement' or 'rendition' rather of fire-rings.
Try that one?
 
There was a guy that was having terrible luck with cometic, in 2007. I am not sure what gasket he was running, but he ended up going back to fire rings.

I think the fancy gasket is phuzion. I had some flexible rings in my 01 for about 2500 miles, and they ended up not holding up. This was back in 2002 or 2003 though. The idea was people weren't sure how the fire rings would hold up on a street truck for 50k, or 100K. They had seen some firerings cracked, so they felt the flexible rings would be the ticket. The ones I used had no reciever groove in the head or block. After 2500 miles or so it blew on a hard run(100hp injectors, comp box) It now has fire rings in it and that was 20,000 miles ago.
 
That sucks.
I have heard Cometic is giving refunds if you send them back the gasket. They want to see the failure so they can fix it better.
Just call them.
 
I have spoken with several guys who are in the same boat! Seems that these gaskets are not holding quite as expected......
 
tony597fitter said:
That sucks.
I have heard Cometic is giving refunds if you send them back the gasket. They want to see the failure so they can fix it better.
Just call them.
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Good idea.:thankyou2:
 
I USED to use them in Duramax world, sent them all the stuff to build us gaskets, and out of the 11 sets of gaskets I've had, 10 failed, the 11th set just sold on ebay.
 
Humm...Interesting.

When I was working at Mercedes Benz, they used an MLS design similar to what Cometic is using.

We had no issues with them untill an engine had to come appart. If the head and block surfaces weren't PERFECT, both being plained they would fail.

Sorry to hear about your luck! Keep us posted to what they do for you.
 
That may be the issue with these. The 3rd gens are having great luck, but they are starting out with two planed surfaces. Most people are just surfacing the head.
 
DieselDood said:
If the head and block surfaces weren't PERFECT, both being plained they would fail.
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I think this is going to be the biggest problem with people using them. With a MLS gasket like Cometic its almost imperative to have the block decked and the head milled before installation to ensure an ideal mating surface. Though it being a fresh design for the 6BT engines it may still need some polishing R&D.

$.02

Did you have your block decked and your head milled before installing the gasket or did you just clean it up?
 
A guy on the DTR (ratsun), rebuilt his motor had both the head and block milled and the Cometic gasket still failed in 1000 miles.
 
Dodgentwo said:
I think our trucks run a little harder than the mercades cars do.
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I wont' argue that... but a twin turbo V12 is nothing to shake a stick at either.

Benz also uses the MLS gaskets on the diesels with no issues. Again not near as hard as we run our trucks, but at least it's a diesel!
 
I have only had one block that did not need a resurface. Every other block that I have pulled was warped at least .006" and take about a full .008" to clean up the warpage and to take out surface blem's. And if a block had a blow out between cylinders, you can forget throwing a gasket at it, the block has to be surfaced.
 
Is fire-ringing still the be all end all sealing solution? It sounds like the rubber coated copper flatout-racing gaskets hold their own, but leak coolant.

I wish there was a middle ground!
 
How flat was the block&head in thousandths, front to back, corner to corner and side to side?
 
No way I wouldut a cometic gasket in a 12v, 24v or CR engine. I have had way too many guys have failures using these gaskets! They may be an option for a stock truck or even a slightly modified (under 100 RWHP over stock) but for anthing else there are just too many failures.
 
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