Closed Cooling, or Not

[Blue Heron]

So assuming closed cooling on both, how soon can I expect to be changing manifolds or risers on a Mercruiser versus a Crusader?

Also, if I can find a low hours used Crusader inboard, how difficult would it be to mate up with my Bravo drive using parts scavenged from my existing setup?

Thanks for all the input.

Dave

[TollyWally]

With FWC manifolds aren't really the issue, it is the risers. Think of them as a consumable. Frequency can depend where you live, generally speaking warmer water shorter interval. I look at mine every 2 years and swap them out every 4 or so. I am being fairly conservative, you can stretch it if you are looking at them frequently enough.

The problem with the mercruiser in my opinion is the castings are not robust enough and leave you with a much smaller margin of error. How much smaller? I don't know.

The price of the parts is part of the equation. My Volvo is cursed with expensive parts, the engineering is good but the swedes are too damn proud of their parts! I bought a new set of manifolds and risers and when I get sufficient ambition I am going to swap out the old Volvo manifolds so I can replenish with inexpensive risers rather than the Swedish ones at 3 x the price.

I don't believe that it would be difficult to hook a Crusader up to your outdrive but I can't speak to that intelligently. I'm not a sterndrive guy. It would seem that a chevy is a chevy. Someone else is bound to chime in with more specific knowledge.

[Blue Heron]

Mercruiser offers a stainless riser elbow. Assuming I stick with Mercruiser on the repower, would a combination of closed cooling and stainless risers be an improvement, or is the stainless just going to cause the corrosion to shift to another part due to galvanic action?
Dave

[TollyWally]

Offhand I'd say that the SS riser coupled with FWC sounds like a good thing and would be an improvement. I'd think that gasketing would serve as at least a partial barrier to any galvanic corrosion shift. In any event the corrosion might be something that could be monitored.

One slight issue to keep in the back of your mind is that stainless often looks pretty good right up until it fails, while ordinary steel gives plenty of warning that things are deteriorating. It might lull you into a false sense of security years down the road.

Maybe you can find a Mercruiser forum or something and see how people like the SS riser and how it stands up. What's it cost? My solution of choice was decent cheap risers that I can change frequently. Higher priced risers that can stand up for extended periods of time might be a better trade off. I don't know.

Here's one little trick that I learned from a boatyard. Since it is quite difficult to remove the rubber exhaust hose once it has sealed and cured to the riser without cutting it I run short pieces of hose to a 6" pipe. When I check my risers I only need buy the short lengths, the bulk of the system remains intact, which makes it much more inexpensive which in turn lets me check my situation more frequently. I thought it was a cheesy halfassed idea until I saw the boatyard owner having it done on his own personal boat. After that, if it's good enough for this guy, it's good enough for me.

Another thing to keep in mind is if this motor has been operated in the salt for a long time you may need to pay extra attention to trying to clean the existing inner passages of the block. If the motor is out maybe it would be worth pulling the freeze plugs. Your motor with FWC will probably run hotter since at least around here in our waters raw h20 cooled motors are notorious for running too cool.

Keep us posted. LOL it's easier and cheaper to learn from others

[Blue Heron]

I was told by the previous owner that the current risers are stainless. When I pull them, I'll see what kind of shape they're in. On the outside, they look a lot better than the manifolds. Assuming he hadn't changed them since he had the engine installed, they have 400 hours on them. On the Mercruisers, there is a short exhaust tube from the riser to an elbow that turns down to the y-pipe. That should be all I would have to replace when installing new risers.