Exhaust manifolds and risers

[Timbo]

It's getting time to replace my exhaust manifolds and risers on my 3200scr, I have the twin 5.7's what is the best ones to use to replace them I've looked at several different manufacturers but don't what ones to go with?

[shrew]

Mercruiser. I would not suggest using 3rd party parts for Engine and drive.

[Kevlar7r]

Not all of us are as rich or persnickety as shrew. :-)



I used sierra and have had no problems. Plus I had quite a bit of extra beer money in my pocket vs. Using mercruiser manifolds.

[mmwjr]

I have used OSCO, Sierra, and Mercs and IMO the only difference is the Mercs came ready to install with a good paint finish, the Sierra as were painted just not the same quality but after 5 years no rust so I guess good enough, and the OSCO were only primed and I had to paint them.

Then you can decide between dry joint or wet joint.

[Timbo]

What's the difference between wet joint and dry joint, is one better than the other.

[mmwjr]

Originally Posted by Timbo

What's the difference between wet joint and dry joint, is one better than the other.

Wet joint is what came with your boat and all mercruisers until sometime in the mid 2000's. The water transfer ports are cast into the units and are near the exhaust port, issues is if the gasket fails water can leak into the exhaust and get back into the engine.

Dry joint only has exhaust port at the gasket and the water port is cast as an external tube so if it leaks its visible externally.

Wet joint has been around as long as inboards and still used by Volvo with an excellent reliability, merc just eliminated this potential fault condition.

[Kevlar7r]

Dry joint is better, and priced accordingly. The gasket surfaces of wet joint are a weak point, but, like mike pointed out, dry joint eliminates that weakness by separating the water transfer from the exhaust transfer.



Its actually hard to explain, pictures do a much better job. Do some googling.

[Timbo]

Thanks all for your help in clearing this up for me I really appreciate it. Now its time to break out a couple more boat units.

[shrew]

Originally Posted by Kevlar7r

Not all of us are as rich or persnickety as shrew. :-)

Geez, you say it like its a bad thing.

[Kevlar7r]

Originally Posted by shrew

Geez, you say it like its a bad thing.

Not at all, in fact there was a twinge of jealousy in my tone! :-)

[jamanati]

I put GLM manifolds/risers on my 3200/5.7L