Air cooled?

[Guest]

I am building a Hartley & Brooks designed 38ft Ferro Cement double ender. Ihave aquired (free and in good working order) from my employer, an ex dumper diesel engine rated at 72hp. The engine has had an easy life and is in good order. Before I spend money on having it overhauled I need some advice if you please.

The diesel is a Deutz F4L912 four cylinder air cooled..............

Doea anyone have any experience of air cooled engines in a marine environment? I have aquired all the technical details of the engine from Deutz website, they specify a marine engine too, the only difference in the spec I can find is the 'optional' protection of the cylinders for salt water environment

<P ID="edit"><FONT SIZE=-1>Edited by lochen on Sun Jun 30 22:51:28 2002 (server time).</FONT></P>

 

[Jcorstorphine]

You need to allow a good supply of fresh air for the cooling otherwise the block and the oil may get too hot. Also exhaust of air cooled engines would normally run dry so you will have to lag the exhaust pipe and you will need a decent sliencer. Many years ago, I had a petrol air cooled engine in a small yacht but the problem with a hot exhaust was solved by fitting a small Jabsco pump off the aux belt and injecting water directly after the exhaust manifold. Result, a cold exaust and no need for a silencer. You also need to watch the resale value of the boat as anything which is "unusual" may detract from the price.

JC

 

[Guest]

Thanks for the response JC. The Deutz engine has ducting mounted on the side with a fan, air goes in and cools an oil cooler and then the cylinders in turn. I had thought that I would fabricate a continuation of the ducting to a swan neck topsides (maybe some of that flexible flue piping). The ducting (for want of a better description) can be configured to cool a hydraulic oil cooler, which I have retained as Im talking to someone else about hydraulic drive systems.
The next problem is how to get rid of the hot/warm air from the engine room. Maybe a drying locker also vented to topside.

Resale value isn't an issue, not when building a ferro boat in the UK and particularly not for me, this is my 'one time' boat, my 'cottage' by the sea.

Regards

barry

 

[sapper]

My own enquiries on the subject indicate that noise can be problematic but not an insurmountable one & I have seen suggestions that an extractor fan to push used air topsides will reduce the amount of hot air recirculating. Lastly Duetz advised painting exposed aluminium, hope this helps.

 

[johmal]

I fitted a Lombardini aircooled deisel in an open launch. Cooling was a problem - in that you needed to make sure that the inlet air is not drawn from the outlet air!

You also need to ensure that the engine can always draw in a much larger volume of air than a water cooled engine would need. (i.e. bigger holes above deck)

John

 

[Guest]

Thanks to everybody so far for your useful and constructive advice. I had heard that air cooled engines were noisier due to lack of a water jacket. I think with modern materials I can minimise this. Your advise has given me confidence in what I had more or less concluded and I feel reassured, again thankyou.

Barry