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Fan cooled oil cooler for Walter v-drive
Posted: May 6th, 2021, 9:16 pm
by Fireriders
Hi all and a question about Walter V-drive. My cooling system on the V-drive is shot. Cover is corroded so bad it pisses out water all around the gasket surface. The actual V-drive is really bad also with corrosion and the bolt holes are shot. Before the salt water eats into the actual gears I want to completely bypass the raw water from the V-drive and go straight to the engine pump. Has anyone replumbed the oil system to a engine oil cooler with a fan? I've been building hot rods since the late 1960's and can't see why this would not be a far better cooling system than raw water that eats it away as it cools. I know boats aren't cars so any input pro or con greatly appreciated.

Re: Fan cooled oil cooler for Walter v-drive
Posted: May 6th, 2021, 9:45 pm
by Viper
I don't think you'll get better heat absorption through air than you would through raw water. If routing through an external cooler is the route you want to take, why not run through a raw water oil cooler like the one you find on the engine for the engine oil.
Have you looked for a rebuilt drive or just a casing and swap the parts?
Re: Fan cooled oil cooler for Walter v-drive
Posted: May 6th, 2021, 10:46 pm
by tomschauer
If you move to an air cooled unit in the bilge, where the air is close to 180 degrees when running at cruise speed, you will need a really big cooler.
With a car, your cooler is seeing ambient temp, not the high temps of engines and transmissions in a confined area with limited air flow.
As viper mentioned, maybe an external water to oil cooler?
Re: Fan cooled oil cooler for Walter v-drive
Posted: May 6th, 2021, 11:47 pm
by bud37
I think you found the reason all that was disconnected.....Just a quick tip, somehow you need to make sure the drives are mechanically sound before you start engineering. I would hate for the cooling to be rigged up only to find the drives are worn out. Consider how long the originals lasted, the raw water cooling works pretty well, and with a dockside flushing system may still be ok......good luck man.
Re: Fan cooled oil cooler for Walter v-drive
Posted: May 7th, 2021, 7:09 am
by Viper
Ya in an air cooled system, you're not going to extract much heat in a compartment where the ambient temperature is 100 degrees under normal running conditions. Even if you're in the tropics, the chances of running in 100 degree raw water is pretty slim. There's a reason why marine application are water cooled. The corrosion associated with a salt water application is just part of life in the marine world but there are things you can do to minimize the effects like regular fresh water flushing.
Re: Fan cooled oil cooler for Walter v-drive
Posted: May 7th, 2021, 11:23 am
by Fireriders
Thanks everyone for the responses. Has given me plenty to think about,. First the budget I work with on my pension will no way let me buy or re-case my V-drive. A remote sea water heat exchanger has very good possibility and like one of the replies mention I will wet the boat and engage the drives. If either is damaged then all is a moot point and will have to take a step back from the whole thing. Like I said the corrosion is extremely bad. If the case isn't leaking into the gear cluster then I will consider myself lucky. I pulled the dipstick and the oil is clean with no water which is very encouraging.
Re: Fan cooled oil cooler for Walter v-drive
Posted: May 7th, 2021, 9:19 pm
by ColRon
Fire riders, Walter is still in business and they have a rebuild service for their drives. You might want to contact them and ask. I recently had some questions regarding the current recommendations regarding using gear lube or 30 weight motor oil Check them out at
www.waltergear.com