Plymouth man
Member
What kind of sealer,thread locker or what do you put on exhaust manifold studs that go in the head on a 440
Exhaust manifold sealer
- Thread starter Plymouth man
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SwissMonaco
New Member
I work as an engine builder and we use Loctite 638 for such things
I wouldn't use Loctite Thread Locker (especially the 638 green) in that application. Since it goes into the water jacket, I'm not sure if it would seal or not, probably not. The main reason is if you break a stud removing the manifold at a later date, it's going to be that much harder to remove the broken stud. Having worked a bit with the 638 myself, I would say that heat from the exhaust would make it useless as a locker anyway.
I would use Permatex #3. It's a slow drying, non-hardening compound that will work up to 400*F. You want to seal the threads so coolant doesn't leak and they don't need to be locked into place. I would rather have the stud back out rather than break.
Also, no gasket under the manifold, just like the factory did.
I'm not a professional engine builder, but I have built a bunch of 440 engines over the years.
I would use Permatex #3. It's a slow drying, non-hardening compound that will work up to 400*F. You want to seal the threads so coolant doesn't leak and they don't need to be locked into place. I would rather have the stud back out rather than break.
Also, no gasket under the manifold, just like the factory did.
I'm not a professional engine builder, but I have built a bunch of 440 engines over the years.
Plymouth man
Member
Thanks but when I took manifolds off it did have gaskets
It should not have gaskets. Unless it's some weird RV engine, it won't have gaskets from the factory.
Just about every big block I've ever seen that has gaskets under the manifold will eventually burn through and leak. If the manifold isn't flat, have a machine shop correct it.
sprice
Active Member
Big John, I have read about the exhaust manifold studs going into the water jacket however mixed readings on exactly which studs. I have read at times its only the end ones. Would be nice to set this straight for next rebuild. Would you know the answer to this on 440 heads? Thanks.
From my observations and reading, it seems that it depends on the casting and/or how deep they drilled the holes.
I've read that earlier heads tend to have just the outer studs in the water jacket and later heads tending to have all the studs in the water jacket, but really nothing that I could say is absolute.
So, there seems to be no set pattern. You could poke into the holes and figure out what ones are in the water jacket or better yet, just treat them all as going into the water jacket.
Plymouth man
Member
Do you know the part number all the part houses are trying to sell me the silicone tube type and ask me for the part number I've surfed the net looking and come up with several different part number types thanks for any reply
Plymouth man
Member
Thanks big john
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