V-Drive Cooling

Sounds like you found the same things I did on the google search, sailboats.   Who knows why they do it that way?, Walters are a bunch of JackA$$''s to deal with from what I've seen and I sure wouldn't rule out they did it for continued sales down the road. If you're just putting it in salt water for the first time then I would think you've got plenty of service left before it needs replacing. I would put a Perko flush on so that it will flush the Vdrive and call it as good as it can be.

I Helped winterize a friends Tige yesterday that had a Marine Power 6 liter engine which I believe is the same base motor as the ZR409.   Anyway the way it was cooled is the hull intake ran through the Vdrive and then on to the raw water pump then to the heat exchanger. I wouldn't be real comfortable trying to figure out how to cool the Vdrive with T fittings after seeing it. There is a reason why the Vdrive is cooled with the coolest water availabe and I don't know what that is. There is also a reason why they didn't think it was necessary to include it in the fresh water loop and I don't know that either. My guess is either the Vdrive needs water cooler than what is circulating through the motor, or they aren't worried about what the salt water will do to it.

How about circulation?

Based on what I've found...

"The t'stat and housing have a unique construction in that when the engine is cold and the t'stat is "closed", it allows full recirculation through the engine loop but little or no coolant passes through the H/E loop."

"As the engine warms up, and the t'stat "opens", it starts to close off the engine recirc loop and shunts coolant through the H/E loop. The hotter the engine gets, less is recirculated in the engine recirc loop and more goes through the H/E - varies with load and engine temp. When the t'stat is fully "open", almost all the coolant runs through the H/E loop and little or no coolant runs through the engine recirc loop."


If the H/E could handle the extra capacity, where could I tap into the lines to get proper coolant flow?

I know this isn't an issue for many, but there really isn't a lot of information about closed cooling on GT-40s. I would be happy to document the process and post some pictures.

I'm sure it's possible, can't think about how exactly it would go off the top of my head though. I would look for a manual about the mid 2000's ZR6 and how things are routed. That motor is fresh water cooled and CC used the Walters at least up to the 226.