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Sealant or No Sealant?

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Tank1949

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For some time, I have been ill. I have healed. I have dual MC Chevy V8s that are antifreeze cooled, except risers and heat exchangers. Salt water passes through risers to cool exhaust, but not exhaust manifold. I ordered riser SS spacers and gaskets from Sierra and will be install them soon. My exhaust manifolds are NOT blocked off where they meet risers (old model); hence I must use the SS spacer. My gaskets didn't come with instructions to use additional sealant between gasket and ss spacer/manifolds and riser surfaces. Should I use a sealant or sandwich the gaskets on or install them DRY? Please advise. THANKS
Order number: --
 
Tank1949 said:
For some time, I have been ill. I have healed. I have dual MC Chevy V8s that are antifreeze cooled, except risers and heat exchangers. Salt water passes through risers to cool exhaust, but not exhaust manifold. I ordered riser SS spacers and gaskets from Sierra and will be install them soon. My exhaust manifolds are NOT blocked off where they meet risers (old model); hence I must use the SS spacer. My gaskets didn't come with instructions to use additional sealant between gasket and ss spacer/manifolds and riser surfaces. Should I use a sealant or sandwich the gaskets on or install them DRY? Please advise. THANKS
Order number: --
Click to expand...
Dry
 
When you say old style,

What is old, a year of boat/engine and or description would work, like long and rectangular with end caps or current style meaning center riser/exit.
 
kghost said:
When you say old style,

What is old, a year of boat/engine and or description would work, like long and rectangular with end caps or current style meaning center riser/exit.
Click to expand...
The top of the exhaust manifolds are open to pass salt water if my motors were raw water cooled. I didn't want to buy new exhaust manifolds. Motors or remans I believe 1987 Chevy v8 blocks, which have never had saltwater in them.
 
You have new style center rise manifolds.

You say risers, Risers are spacers between manifold and ELBOW. Is this what you have?

Many people use conflicting descriptions.

A manifold is a manifold.
A riser is a spacer to raise the elbow higher based on engine placement vs boat design (typically used with thru hull exhaust)
An elbow is a elbow, NOT a riser.

Just to be clear!

Make sure you file the surfaces where the fiber gaskets will mate to, Make sure they are flat with NO imperfections that could lead to a leak.
Then dry will work fine. If I remember when I get home from work I will review the service manual and see what they recommend for closed cooling systems gasket prep.
 
What you are calling "spacers" are in fact stainless block-off plates. AS Kghost said, "Spacers" also referred to as "risers" by some, are extensions that fit between the exhaust manifold and the elbow to raise the elbow so that it is above the water line. Do as instructed, file the mating surfaces to verify both the manifold and elbow are flat. Gaskets above and below block-off plate. I use a very thin coat of Ultra Black or Perfect Seal.
 
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