Upgrade to closed cooling?

[gtfireftr]

Re-powering both engines..... 4.3 Vortec 4 barrel... Alpha 1 gen 2....
My question is it worth doing a closed cooling upgrade considering I am installing new manifolds, risers, and new engines?
Not sure if the outdrives have an effect on closed cooling.... Never had closed cooling, but if I am going to change I think now is the time...
Any advice is greatly appreciated

 

[SCORPIO]

Now is the time if you are going to do it, BEFORE you run any salt through the engines. If you are planning on keeping the boat I'd say DO IT! I did the same thing when I repowered my 89 300 DA. The only issue is with Alpha's the water pump doesn't supply enough water for a full system that cools the manifolds, but you can install a half system which is block and intake only. The exhaust manifolds are raw water cooled. If you want a full system, you will need to install crank mounted water pumps and thru hulls. I opted for half systems on my 5.7's as I had an internal corrosion failure that caused me to loose an engine to water injestion.

OH, I see you have 4.3's, you may be able to use full systems since you have V-6's not V-8's. Call the company you plan on getting the kits from and ask their opinion about the full system.

FWC makes winterizing a piece of cake and no worries about internal corrosion. Also since it's a pressurized system, you can run a hotter thermostat which allows the engine to run warmer and more efficiently.

 

[NorCal Boater]

My Cobalt has FWC on the small block GM motor. However, because it is a jackshaft model raw water is pulled from the bottom of the boat, like an inboard, through the heat exchanger and out the exhaust. I still have a water pump in the outdrive supposedly to cool the upper gear case on the drive but I think I could accomplish the same thing with a drive shower.

There are Merc parts available to block the water passage through the gimbal housing.

 

[Bt Doctur]

Its best just to cut the hose in the housing and let it flow thru the drive to cool it

 

[NorCal Boater]

Its best just to cut the hose in the housing and let it flow thru the drive to cool it

Actually, there has never been a hose in the housing. Raw water goes in the bottom and out where the hose would normally connect.