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Riser Pass Thru Plate

smbdck

New member
Hello,
I have twin 8.1's with fresh water heated risers. There are 2 metal plates on each riser, a pass thru and a blocking plate. I understand the need for the blocking plate but not the pass thru plate. Is the pass thru plate necessary and can just a gasket be placed there instead ?

Thank You
Smbdck
 
the 8.1 uses what they call "wing plates" and they come in the blocking and pass thru configurations. I suspect it is due to the 'wing' around the exhaust passage. My understanding is that it is there to "catch" any water (which shouldn't be in that area of the passage).

on the 'heated riser' configuration the block off version goes between a pair of gaskets and that assembly goes between the riser and the elbow. (Same assembly would go between elbow and manifold in a no-riser setup.) the riser-manifold uses the pass thru plate between a pair of gaskets. I don't see the need for the lower wing plate if the upper one is installed. as a general rule, unless they are damaged, either plate can be reused with new gaskets....
 
the 8.1 uses what they call "wing plates" and they come in the blocking and pass thru configurations. I suspect it is due to the 'wing' around the exhaust passage. My understanding is that it is there to "catch" any water (which shouldn't be in that area of the passage).

on the 'heated riser' configuration the block off version goes between a pair of gaskets and that assembly goes between the riser and the elbow. (Same assembly would go between elbow and manifold in a no-riser setup.) the riser-manifold uses the pass thru plate between a pair of gaskets. I don't see the need for the lower wing plate if the upper one is installed. as a general rule, unless they are damaged, either plate can be reused with new gaskets....

Thanks for your response. I agree, there really is no need for the lower pass thru wing plate. I guess there is no way to contact Crusader anymore and ask them.
 
There Tech support dept still answers the phone - but, to be honest, I haven't called in a couple months. That said, I wouldn't expect any answer provided to deviate from the original (production) configuration.....
 
I believe the wing plates are designed to catch and boil off any water/moisture that may run down the inside of the riser or elbow to keep it out of the engine.
 
In the MERCRUISER world, they are called "turbulators" and catch condensation that forms on the inside of the elbows when engine first starts under most weather conditions.
 
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