Dry Joint and Closed Cooling on Gen VI 7.4

SDSeville

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Hi Everyone,
I am finally getting around to repowering my Maxum with a remanufactured 7.4. The shop is recommending a Dry Joint exhaust manifold and closed cooling. They said this way I wouldn't have to worry about hydrolock caused by leaking manifolds or risers in the future. I get the closed cooling, but how does Dry Joint help?
Thanks!
 

Scott Danforth

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because with dry joint design, there is NO water near the exhaust gasket. so no chance of water leaking into the exhaust manifold from the joint.
 

SDSeville

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because with dry joint design, there is NO water near the exhaust gasket. so no chance of water leaking into the exhaust manifold from the joint.

Thanks. This i sprobably a dumb question, but -- so this protects against gasket failures, but how about rusted through risers?
 

Scott Danforth

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nothing prevents rusted thru risers except replacing every 5-7 years if your in salt water
 

tpenfield

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Rusted through elbows (and maybe risers if you have both) will still need to be attended to. But the maintenance interval will be longer, and almost non-existent in fresh water. The exhaust manifolds should be good for a lifetime with a full closed cooling setup.
 

SDSeville

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Thanks Scott and Ted! It looks like the Dry Joint (and of course the closed cooling) is worth the little extra money. I don't want to go thru this repowering thing again for a long time.
 

achris

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Thanks Scott and Ted! It looks like the Dry Joint (and of course the closed cooling) is worth the little extra money. I don't want to go thru this repowering thing again for a long time.

:thumb:

Dry-joint man flows.jpg
 

HT32BSX115

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Why hasn't Merc produced a dry joint for the 7.4/8.2 ?

Might have something to do with the "end-of-life" of the 454/502. Don't remember when Merc stopped offering the 7.4 but that would probably have something to do with it.

I sure wish they did. There are after markets offering "dry" stainless/welded risers that are dry joint, but I think they bolt to the "regular" manifold........so they don't eliminate the leak-point. You still need to seal the top of the manifold (or extension) with some sort of gasket.

The shop is recommending a Dry Joint exhaust manifold and closed cooling.
Please post it here when you find those manifolds and risers for your 7.4L!

Lot of people would like to do the same thing!!


It looks like the Dry Joint (and of course the closed cooling) is worth the little extra money. I don't want to go thru this repowering thing again for a long time.

I'll also add that I added closed cooling to the 7.4L Bravo in 2006 when I repowered my OMG 460 King Kobra powered Fourwinns.

It's a San Juan Engr full system and was worth every penny! About 2 years ago, I had a riser gasket leak coolant iinto the exhaust. It didn't seem to hurt anything because I probably caught it early.

If I had "dry-joint" exhaust, that would have NEVER happened!

But so far, I have not been able to find dry-joint manifolds for a 454. If I had known this, I would have paid a little more when I was repowering and gotten the 496/BIII I found!
 
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