EXHAUST

[mrjamieson]

Hello folks, I have recently repowered my 1992 5.7L Wellcraft to a Marine Power 5.7L vortec, carb, EST and electric fuel pump engine. Can I upgrade my exhaust to a dry joint?? I currently have a wet joint 4 in. center riser. ThANKS

 

[Bondo]

Ayuh,..... Welcome Aboard,...... It's yer boat, 'n you can do anything you want to it,.....

You may, or may not need to change out the t-stat housing in the process,....

 

[mrjamieson]

I should have been clearer. I meant, Is it possible to convert to a "dry joint" set up. If possible, any ideas where to research what else I have to change. Like you mentioned, the t-stat housing.

 

[achris]

First thing I would do is determine which cooling system flow diagram applies to your engine (in the Merc service manuals).. Then post that info here.

Next I would ask @achris to post his list of part numbers for the conversion... Oh wait, that's me.

You should only need the manifolds and elbows. All the other parts should be 'plug and pray'.

Wet joint

Manifolds
V8 – 860246A15

7° (4”) parts

Exhaust elbow – 807988A03
Inter elbows (with NO riser)
V8 - 11086T (port)
V8 - 14343T (stbd)
Y-pipe - 807130A4 (Originally -44266T)

Dry Joint

Manifolds
V8 – 865735A02

7° parts

Exhaust elbow – 864309T02
Inter elbow (with NO riser)
V8 - 11086T (port)
V8 - 14343T (stbd)
Y-pipe - 807130A4

Research done....

Chris........

 

[achris]

Oh, you'll need a couple of manifold/elbow gaskets too.
27-864850A02

Chris......

 

[mrjamieson]

Thanks achris, I'll check the #'s and flow diagram. Those dry fit #'s are what I got to. Thanks

 

[mrjamieson]

BPI has some reasonably priced kits. # BPISBDJ7 is the one I believe I need.

 

[Lou C]

Barr Marine also makes a good aftermarket version of the dry joint....

 

[mrjamieson]

Great, I'll check them out. I wasn't sure if we could use company names on these forums.

 

[Bt Doctur]

dry joint gaskets are kinds of expensive

 

[Lou C]

The whole dry joint system is a good deal more expensive but if you are in salt water I'd say it's definitely worth it. In fresh water where exhaust corrosion is not such a big issue it might not be as much. Here in the salt pond if I could fit the dry joint exhaust to my OMC engine (it now has the late OMC/Volvo style wet joint) then I would spend the extra for it.

 

[achris]

The dry joint manifolds on my engine are 16 years old (they're original). The elbows are 10 years, and that's all salt running (we have virtually no freshwater here. Even our tap water is some of the hardest in the developed world). As much as I absolutely hate to promote Mercury (search up my history with a certain oil leak ), a lot of their products do seem superior. I used to be a MerCruiser/Mariner dealer and owned a shop. As a dealer I did try the cheaper aftermarket products like bellows, impellers, seals etc, and unfortunately the extra you pay for the OEM is worth it. Exhaust componentry is also one of those. Merc's manifolds and elbows are ceramic coated, and I don't think any of the others are... I think, if you intend keeping the boat for more than the next 5 years, then the extra up front cost of the Merc manifolds vs their longevity makes them the cheaper option...

Just my perspective...

Chris....

 

[mrjamieson]

My thoughts exactly achris. I own a few gas stations/shops/marts and I use OEM as much as possible. The extra $ is definitely worth it.

 

[Lou C]

If the Merc OEM will last that long in salt then over time it would be cheaper because in that time frame (10 years) you’d wind up replacing most aftermarket 2x usually. I chose Barr when I did mine because I read in here they cast for some OEMs like Volvo Penta. Not sure if there is a difference between what they cast for VP & their own label but at almost 5 years they look good. To me just the idea that the dry joint prevents the deterioration of the vulnerable wet joint that will let salt water corrode exhaust valves is a major improvement.

 

[76SeaRay]

I went with HGE manifolds and risers on my scratch build 5.7L Vortec. I went further though and installed closed cooling with the dry joint system.

 

[mrjamieson]

I went with HGE manifolds and risers on my scratch build 5.7L Vortec. I went further though and installed closed cooling with the dry joint system.

I would like to do that next winter. Can you give me some pointers?

 

[achris]

I would like to do that next winter. Can you give me some pointers?

Be aware that if you run salt water through a block it's not advisable to put closed cooling on at a later date. If you want closed cooling, do it right from the start...

Chris...

 

[Lou C]

Yep, once cast iron starts corroding, you can never really stop the flaking. It corrodes differently than cast aluminum. Closed cooling is really only for a new engine or a reman one that came from an auto application where antifreeze was used in the cooling system.

 

[mrjamieson]

Be aware that if you run salt water through a block it's not advisable to put closed cooling on at a later date. If you want closed cooling, do it right from the start...

Chris...

The engine, transom assy, and outdrive are brand new. Hasn't been in the water yet. It was a complete boat rebuild.

 

[Lou C]

Well then you can! You now have to decide If you have enough cooling water flow to be able to install a full system (including the exhaust manifolds) or only a half system (block only).