I bought a cometic MLS off another site, at the time i was in iraq, and hadnt had a chance to do alot of research on this due to crappy internet, well after doing some reading here i'm thinkin what i have isnt gonna work for me, its a .060 gasket, is this to thick to use, i plan on pulling the head after hunting season, but what i've been reading is i should have a .010 thickness?? Can anyone shed some light on this, did i get something i can't use? Thanks for any info..

Capn

 

I think I would be more worried about it blowing after the install i put two on and both let go i have had stock ones last 10 times longer good luck if you put it on

 

Ok i thought from what i was seeing on here that the way to go was the cometic gasket? So what is this "marine" gasket i've read about, should i just go with something like that? Thanks for any info..

Capn

 

The Stock gasket comes in .10 &.20 over sizes and if your really going to push it hard get the head o-ringed when its off The the stock ones do a good job up to 500hp and 50lbs of boost or so with out o-rings ,hows it doing now ??

 

The stock gasket compresses to roughly .060, a .020" over would be .080"
Your Cometic is a stock thickness replacement. I would recommend you go with a Cummins gasket.

 

O/S refers to the bore oversize not thickness.

 

ok hopefully this will clear up the confusion, cause i'm confused now...lol heres whats on the package.

Cummins 24v Diesel 98-02
.060" MLS 4.020-4.188
C 5855-060
Part # H2684

I dont want to go with oringing, just looking for a good gasket, i'm pushing 45 lbs boost now, and twins isnt out of the picture, i have new springs, and head studs ready to go in... thanks for anymore info..

Capn

 

The most important thing is , to not let any coolant sit in the crank case , condensation can rust a lot of things and the coolant eats away at the bearings , letting the coolant stand in there for long can lead to a major rebuild .
As far the using the gasket , I have see a lot of posts complaining about those gaskets , then for the thickness , its depends on a number of things , what your are doing with the different gaskets [ and other parts ] is adjusting the deck height & compression ratio , as the head gets surfaced to straighten after overheating / blowing gaskets ect. , you are changing these numbers , so going back to stock , or for a specific mod .
The best thing to do is find a machine shop that knows these engines , let them know what your plans are , then get the gasket that fits the need you have , relative to the above numbers .
But if the coolant is been in the crank case for long , you need to drop the pan to check the rods & mains , unscrew the drain plug , all but the last thread or two and see if any water/coolant drips out , if not you may be OK .

 

Go with a stock gasket. Drain the block prior to head removal. The best is too pull the hose off for the heater hose at the front of the engine on the right side of the truck beside the alternator. That's a 1/2in heater connection is used for the heater line and/or tranny heat exchanger. It drain the block enough to drop the coolant level so you don't get coolant in the cylinders on a head pull. Clean, clean the block surface. Don't remove metal buddy, thats bad thing, just the old gasket material. Rust starts really quickly, so put on white grease on the surface. You thinking about new head bolts? The old ones might be stretched, still good, but.... New ones are cheap. How hard are you going to push the new head gasket? Why you replacing the old gasket? I've done three this year, and the year isn't done yet. You have to kill the original prior to is removal. My last three gaskets where only whimpy kills but still a kill. It makes a mess, but makes it easier to justify working on the truck. I lived with a small leak, for awhile last year. A easy weekend job, if you drink a few beers, it's not that bad of a job.

 

Nope, not for this application.

IMO you are already pushing the limit with out o-rings, and twins will secure it.
If you do a search on the Cometic gasket you will find my post with the build up of mine with all the pictures. It was with one of Cometics first MLS gaskets that Piers and Harry got in to beta test for the 12v so I don't know what/if they have made any changes in the last year.
Cometic makes another gasket called a Phusion that has gas filled rings for the fire ring but I have no personal experience with it.
We all had high hopes that the Cometic MLS would fill the need for the mid hp guys but it didnt work out for us.
Pretty sure you dont want to hear it but....my recomendation is to get your head decked and o-ringed by a reputable shop (there are as many bad o-ring jobs as good ones) and make sure you do your re-torques or you will be doing this all over again soon enough.
You can go with a .020" thicker gasket and that will lower you comp roughly 1 point to help the gasket live but lower comp has some downsides to it also.

 

Thanks for all the info guys, I dont think mine has blown yet, but i've got new head studs and springs to put in so just thought it would be a good time to change the gasket, not forsure if i dont have a small leak internally somewhere, my coolant seems to be going down every couple of weeks? No external leaks though, seems to be running fine so maybe thats just me? I'll do some calling around to check on oringing, not to many shops here into the diesels yet i'm finding out...grrrr once again thanks for the info..

Capn Happy Turkey Day!!

 

people have had lots of issues with the cometic. Scheid recommends some crazy clamping force for their version. My guess is theres just no real replacement for o-rings out there yet.
If youre in there for all that work, id do the o-rings too if you can swing it.
some shops have quick turn-around times if you send it out.

 

Scheids requires 14mm studs, although the ARP 625 studs may be enough. The Phusion gasket that Paul mentioned also required a like-new surface finish on the head and block. Seems cheaper to get the head decked if needed and o-ringed than decking the head and block, which would require pulling the engine.

 

My 12 valver is down right now with a blown head gasket.

What exactly is O-ringing and what are the benefits ?

What's a "ball park" cost for O-ringing a head ?