Headgaskets Aluminum Heads

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Rat Bastid said:
If everything is right, they are better gaskets. They way they seal is better. But, you can’t have a rough surface and they need to be retorqued. Plus, you can get them with about any bore size and any thickness you need. That’s a big deal IF you want to keep crevice volumes down and IF you think compression matters (spoiler alert: I think it matters…a lot).
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Ah, crevice volumes. I wondered about that when I put my 273 together and used generic small block gaskets with a big hole. Oh well, 9.68/1 is fine for a cruiser. A race motor? I would have done something different.
 
Rat Bastid said:
If everything is right, they are better gaskets. They way they seal is better. But, you can’t have a rough surface and they need to be retorqued. Plus, you can get them with about any bore size and any thickness you need. That’s a big deal IF you want to keep crevice volumes down and IF you think compression matters (spoiler alert: I think it matters…a lot).
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Nitrous, turbo, supercharged may be another reason because MLS is supposed to tolerate higher pressures. But yes block and head must be machined to high standard for them to work. MLS is supposed to be reusable too so that another benefit.

The FelPro 1008 met all of my needs and I didn't want to deal with potential leaks of MLS when I had no need for any of their benefits. I looked into MLS and carefully considered and went with what I thought was right for my particular setup. If I had forced induction probably would have leaned MLS.
 
Only gaskets I have ever sprayed anything on were the stamped steel shim style. I always use Copper Coat.
 
I like the Cometic/MLS because as the head expands at a different rate than the block, the leaves of the MLS are free to expand at different rates against one another so they minimize stress in the gasket itself. A composite gasket might just tear apart internally.

Full disclosure, I've not used any of the other gaskets in this thread. I've done a dozen Neon heads and a billion all-aluminum motors (motorcycle).
 
jos51700 said:
I like the Cometic/MLS because as the head expands at a different rate than the block, the leaves of the MLS are free to expand at different rates against one another so they minimize stress in the gasket itself. A composite gasket might just tear apart internally.

Full disclosure, I've not used any of the other gaskets in this thread. I've done a dozen Neon heads and a billion all-aluminum motors (motorcycle).
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Some of those bikes take special care when torquing them say cometic.
Volvo's, done many. Iron block w/aluminum head. They end up near 90 lbs but it's the 2 step then 90 degrees more 'torque angle' deal. No issues, or her than porosity in the rear passage 'we weld those up and flatten the head'.
Theres really no issue with by metal motors that imo wasn't flat out a design flaw in the core.
 
jos51700 said:
I like the Cometic/MLS because as the head expands at a different rate than the block, the leaves of the MLS are free to expand at different rates against one another so they minimize stress in the gasket itself. A composite gasket might just tear apart internally.

Full disclosure, I've not used any of the other gaskets in this thread. I've done a dozen Neon heads and a billion all-aluminum motors (motorcycle).
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Not only do the heads expand, every time there is a firing cycle the head lifts away from the block. Those embossed trenches in the MLS gaskets basically function as pneumatic springs that follow the head as it lifts from the block and keeps the combustion sealed.
 
Rat Bastid said:
Not only do the heads expand, every time there is a firing cycle the head lifts away from the block. Those embossed trenches in the MLS gaskets basically function as pneumatic springs that follow the head as it lifts from the block and keeps the combustion sealed.
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Yup. Very similar in the way rod bolts stretch with every revolution. Same principle, but different forces involved.
 
Got to be careful, no one wants to find fire ring depressions when they pull a set of alloy heads.
 
Bakerlite said:
Real world? A real would you don't live in because your not one of these "high end builders' you mention.. Gimme a break :rolleyes:
Have you ever had to coat them? Do you think spraying copper paint on a rubber surface is a game changer?
If you're a "high end" builder you are most likely to use an upgraded gasket instead of trying to spray seal one that's not up to the job.
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I think I will just trust the best builders in the business and I won't give out names because that's not necessary but hopefully you won't feel too left out as your name didn't make the list. Have a great day
 
Lower compression engines we've been fine with Fel-Pros. Engines with more compression we use Cometic.
 
Begs to question, are 1008 a "MLS" gasket? They refer to them as "Steel core laminate".
 
'68cuda416 said:
I think I will just trust the best builders in the business and I won't give out names because that's not necessary but hopefully you won't feel too left out as your name didn't make the list. Have a great day
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LOL, your just too funny..
I don't need to make someones list.. do you?
It's not important to me. "Lists" don't pay my bills.
All I have to do is make sure my customers are happy and get good value for money and at the moment I'm not coating Cometics to do so.
 
Fwiw The mls/cometics I sprayed with copper coat.. were being reused, that's my experience with them during a tear down. You may find the coating.. worn through on the Impressions 'also a music group' if said movement is happening.
I just want to mention that I had a customer call cometic and ask what his head gaskets needed to be torqued to and is 360 and a guy on the phone told him 75 lb... I laughed n said not on my name, fk that. 95.

Sometimes there are other variables as well like it didn't quite get the surface finish so they spray a little shellac so to speak. Builders shmuilders.
Everybody rates a builder differently and everybody builds different **** for different things there are great lawn mower engine builders too ...simply because their engines don't blow apart and they last. Let's not get too loose with words/definites...you may wake the gurus.:popcorn:
 
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'68cuda416 said:
Also as a FYI Cometic states on their site and will probably tell you if directly asked not to put anything on their gaskets but my builder and MANY others also copper coat their gaskets as they do have a history of seeping some water.
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The auto parts guys and the sealant manufacturers push the concept that gaskets need sealants. You would think that gasket manufacturers know what they are doing, especially those like Cometic. If you need a sealant, especially silicone, there is a gap that needs to be filled, and that should be addressed by a machinist. Furthermore using silicone on engine parts is falling out of style. Too many engine builders have found damaged engines due to the silicone finding its way into oil passages. Engine builders like for Indy Cars F1 and NASCAR do not use silicone on their engines. Many (like Cosworth, Ferrari, and Rolls Royce) use Hylomar which is a non-drying compound. There, the parts can be removed and replaced without cleaning off the residue. This is a great advantage when rebuilding engines at the track in between rounds.
 
Jean Genibrel said:
The auto parts guys and the sealant manufacturers push the concept that gaskets need sealants. You would think that gasket manufacturers know what they are doing, especially those like Cometic. If you need a sealant, especially silicone, there is a gap that needs to be filled, and that should be addressed by a machinist. Furthermore using silicone on engine parts is falling out of style. Too many engine builders have found damaged engines due to the silicone finding its way into oil passages. Engine builders like for Indy Cars F1 and NASCAR do not use silicone on their engines. Many (like Cosworth, Ferrari, and Rolls Royce) use Hylomar which is a non-drying compound. There, the parts can be removed and replaced without cleaning off the residue. This is a great advantage when rebuilding engines at the track in between rounds.
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Who said anything about silicone? I was talking about copper coat....but since you brought it up it is also common practice by builders IF they feel the need to finger smear a very light coat around the water ports of the Cometics as well. Not saying everyone does it but I know many that have and or on certain engines with no adverse side effects. The point of the matter is this.....in all aspects of life there are usually instructions to a certain degree but then real world and reality set in and guys have figured out what actually works.
 
Rat Bastid said:
I don’t bother. I back them off and torque them again. That is the correct way to do it.

Of course, you’ll say it’s wrong so it must be because you know everything, even if it goes against what Cometic says.
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You are right. When you "torque" a fastener all you measure is the friction that is present between the threads and the surface of the underside of the nut or bolt. If you try to check the torque on an already installed fastener, you will get a reading for static friction which means nothing. The proper method to retorque a fastener is to break it loose and then retorque it. This will not tell you what the tension was in the fastener before you loosened it, but it will be appropriately torqued. Of course the right way to "torque" fasteners is by the stretch method or the torque-angle method.
 
Jean Genibrel said:
The proper method to retorque a fastener is to break it loose and then retorque it.
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You don't break them "loose" so to speak, you back them off slightly, keeping some tension on the fastener and re tension.
A reference mark on the fastener will tell you all you need to know when investigating these issues.
 
Getting 1008.

stroker11.jpg
 
That looks like a block of flats sitting on that engine.
 
The Mopar spray was a combo of soybean oil, Teflon, & cellulose fibers, and the instructions for the new MLS gasket installation was to hang the gasket & drown it till it dripped from in between the layers, which were stainless with thin sheets of Teflon sandwiched in between.
Using Copper spray gasket or teflon spray or paste isn't to "seal", it's to prevent damage to the sealing surfaces as they "itch across" the surfaces during expansion/contraction cycles.
 
I think allot of guys on here have the blocks painted black and/or can't see with a crap or it could be they just don't put any miles on their stuff :lol:
 
lead69 said:
I think allot of guys on here have the blocks painted black and/or can't see with a crap or it could be they just don't put any miles on their stuff :lol:
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Some of my stuff was very low mile, hard mile but low mile. I'd say my stuff is still low mile, my 67 only gets driven about 50 -75 miles a year on the street with a 4.30 gear, it's the only car I have left, my old high school car in my avatar.
 
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