So I got some custom made cometic MLS gaskets for my 412. 4.200 x .030".

So anyhow, there idea of an MLS gasket is 3 shims, riveted together in three spots.

Kinda weird.

Any thoughts ?

-- Joe

 

Any idea what the final compression will be?
Aluminum heads?
I was thinking MLS for the Bigblock build, but thought since we're using the iron heads there wouldn't be any benifit because it'll be iron heads to iron block-- no diff in heating & cooling of block//heads.

Post up how they work for you!

 

Gonna be 10.81:1 with alum afr heads.

These rivets are kinda freaking me out. I'm tempted to drill them. Why would they rivet the gaskets together.

-- Joe

 

Is that an option to get rid of?? If they hold the ply's together, how would that affect the " movement " around the bores//water jackets?

( edit )

I would think the rivs wouldn't cause a problem-- aren't they out side of the head//block mating area?

I miss my '74 Camaro : (

 

Dowel pins on the deck should center the gaskets i'd think. ?

This is my third 2nd gen.. I had a 79, a 78, and now another 79. I like the interior, the 'style'. I'm put off by how much the car weighs. You need another 100hp to run the same ET and MPH as a thirdgen.. Lame huh?

Unfortunately, with mortgages, horses, etc I can't afford the '67 Camaro I really want to build

-- Joe

 

I believe rivets may be holding the assembly in a way that allows the expanding//contracting of the MLS to be more controlled.?.?

Did you get copper or composite?

 

I use a MLS gaskets on my engine. Buy some copper spray and coat both sides of the head gasket. You can reuse the gaskets as many times as you want unless you somehow damage them. It's the last head gasket you'll have to buy.

MLS = Multi Layer Steel. They're riveted together because it keeps them lined up as a set. The rivets should not cause interference anywhere in the installation.

 

The rivets are just there to keep the 3 pieces aligned. You can and may have to remove them, I had to remove mine. It was also very difficult to get the gasket on, the holes for the dowel pins are exactly the right diameter so you may have to do what I did and slightly elongate one hole. It may be that the dowel pins on my block were that few thousandths off. Not sure what the story is, but thought I'd mention it.

My machinist told me to use the Permatex high tack spray rather than copper coat on them so thats what I did. So far I am very pleased with them.

 

Wow. Well. We've got some opposing opinions here.. darn..

I expected a felpro type MLS gasket, you know, like metal shims compressed together with a synthetic. But that is fine.. I'm concerned with a couple things:

1) I don't know wtf a 'surface roughness of 50' is..

2) The block was decked. It had been rusty, and the deck surface has some pits. A normal gasket I'd think would be ok with that.

3) I had some flash rust on the deck surface overnight in a small spot behind #7 and #8, even with the bag on. Oiled it down. WIll probably just rub it out with emory cloth, but still.

4) I'm not convinced the rivits won't either hang the head up, or just screw up the head surface..

I've heard good and bad things about cometic. Some google searches revealed a lot of water leaks with the ford guys.. I'm a bit worried over these $200 gaskets

-- Joe

 

Well after visiting their website I can say they changed the gasket because it says theres a .001 viton rubber layer on the shim and the shims on mine were bare metal.

I cant remember where exactly the rivets were, but the lower one was in conflict with the block. I think the others are near the edges of the lifter valley and those IIRC hit the block as well. I cant remember if I asked them or it was in some instructions the gaskets came with, but the rivets are not needed on an assembled motor. I think I probably asked them because it was made pretty clear the surface absolutely has to be flat. Unlike a composite gasket that can essentially flow when compressed during install and fill voids, the metal shims will not do that.

Cant tell you on the roughness, has to do with the surface finish. The guy that I had machine my block and heads has a really nice CNC machine for engines and parts and finished both accordingly. I cleaned it, sprayed the gaskets (both sides) and assembled it.

 

Not a problem with mine, and I did reuse them with copper rtv spray on both sides. The rivets are outside of any clamping area.

 

I guess I'll call them Monday and see what they say. I guess I'm just not all that convinced the heads will compress the rivets without the rivets ruining the heads or hanging up the gasket.

I'm only used to the felpro type MLS, which is 1 peice with a fire ring.

Thanks for the insight guys. My heads won't be here until the beginning of march (AFR = slooooow) so I've got some time.

Thanks again.

-- Joe

 

the rivets should be on the outside of the deck. They shouldn't interfere with the heads. I built hundreds of motors with cometics and assembled them dry and never had any comebacks.

 

I had a set and the rivetted portion was also outside the block/head surface. I had no interference problems.