6.2L Mercruiser MIE: Close Cooled Dry Joint Exhaust. Convert From Cold to Warm Riser?

Greg_E

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Feb 17, 2009
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I will be replacing the exhaust manifolds, risers and elbows. The old parts were also dry joint style. When I removed the parts I noticed that the system was installed as a cold riser setup. From what I have read, the warm riser setup will help minimize moisture forming in the exhaust so I see that as a plus. Also, if the engine coolant circulates through the riser it would eliminate or at least extend the time between replacement of the risers. The elbows would still need to be replaced every 3 years as I have the boat in saltwater.
It looks fairly simple to make the change. The block off gasket would move from manifold to the joint between the riser and elbow and the full flow gasket would go between the manifold and riser. Also the hose nipple on the top of the manifold would move to the riser and a plug put in it's place. Provided the coolant hoses are long enough, they would connect to the relocated hose nipple on the riser. Is that all there is to it, and is this a worthwhile change?
 

Greg_E

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Thanks for confirming that A.D. Even if there was no benefit at all, It will save having to replace the risers every three years. That saves about $400.

I read somewhere that Mercruiser was no longer making the turbulator style gaskets and went back to the flat gaskets. Do you happen to know why that was done? They do look like they restrict exhaust gases quite a bit compared to a gasket that just matches the shape of the casting.
 

alldodge

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Mar 8, 2009
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There is a cost savings, my guess is yours was not changed because the manufacture did not want to be bothered.

So far as the turbulator gaskets, have not heard that Mecr was not making them. Have also been able to find them

27-864850A02 with restrictor
27-864549A02 block off
27-864547A02 full flow

Note: Restrictor side is place on same side and water inlet hose connection
 

Greg_E

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So far as the turbulator gaskets, have not heard that Mecr was not making them. Have also been able to find them

Just something I read on the internet. I don't remember where. I didn't know if it was true or not which is why I asked. Thanks.
 
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