Mounting exhaust manifolds.

The heads were surfaced and the manifolds are surfaced.

"People say.." "word on the street" is metal to metal was factory.

So, dry metal to metal?
metal with some kind of goo between metal?
or use a gasket?
Which gasket ? Like a copper gasket or a Mr. Gasket?

 

I use copper gaskets. Run the car a while then retorque them. They work great and can be reused many times

 

If both are surfaced, matę them up dry. No gasket needed

 

My go to is RemFlex. NEVER a problem.

Tom T.

 

Put them without gaskets if they leak you could always add the gasket.

 

I usually ended up replacing gaskets after awhile, so I finally switched to no gaskets and have not had any problems since

 

It was not an uncommon practice back in the day to go metal to metal. No gasket, goo, etc. You just have to make sure when you are rebuilding an engine that the mating surfaces are flat enough to go a second round, if not you will have to resurface them.

Tommy

 

Typical gaskets act as an insulator, manifolds run hotter.

If the head and manifold are FLAT and SMOOTH, leave the gasket out.

 

And use the correct ramp lock bolts torqued to 18 foot lbs.. these allow the manifold to move as it expands, and prevents them from cracking.

https://www.stage1restoration.com/product/bolt-kit-455-exhaust-manifold-bolt-kit/

JW

 

So, since I sent you the correct exhaust manifold bolts does that mean you plan to mount my manifolds without gaskets? You had previously mentioned using gaskets. I'm told that my manifolds have been surfaced flat before being sent to you. Or are gaskets recommended with aluminum heads and iron manifolds?

 

Remflex gaskets for sure! No leaks ever. Arp bolts

 

Two issues to be concerned with in your Alum head/ Ported cast iron manifold combo Ray..

Dramatic expansion rate differences, and the associated heat transfer are one concern..

But the overriding concern with your installation, in my mind, is galvanic corrosion due to the dissimilar metals. If there was a plated steel shim exhaust gasket available, like the OEM's use in a cast iron manifold/alum head combo, then that would be ideal. There is no such gasket to my knowledge,so we are going to use the big soft remflex gaskets, with your ramp lock bolts at the factory specificed torque, to allow the manifolds to wiggle around on the heads as they expand and contract.

This is not the most ideal situation for heat transfer back to the head, but you have to pick your battles.. I am much more concerned with the ported manifolds cracking, than I am about them warping..

JW

 

Thanks for the explanation, Jim. I understand about galvanic corrosion so, gaskets it is.

 

Above advice given with an assumption that the heads were iron--since "aluminum" was never mentioned in original post.

 

In my case as OP, I am dealing with iron heads and manifolds.
I knew the factory put them together without gaskets, but I was unsure if that was a cost savings decision, or an engineering decision.

 

I’m sure someone will correct me if I’m wrong but it seems that when the parts are new are flat then it’s ideal for reliability to go without gaskets. It wasn’t to save $, but to have one less gasket to eventually fail.

 

Jon, use the correct bolts, torque to 18 ft lbs, and your set.. no gaskets needed on yours.

JW

 

I believe Todd has the correct bolts if you need new ones.

 

I'm pretty sure I bought a set from Todd already. Now I just need to find where they were put.

I have a feeling I'm going to be saying that a lot coming up. I bought components while taking things apart, but that was years ago.
I did find all my original heater box bolts. 1 down.

 

Yep, I have Bolts!!! (thanks for the referrals guys. I see them and they are appreciated!!!)