ken_ichikawa Posted January 25, 2011 Share Posted January 25, 2011 What'll happen if you water cool an aircooled engine? I'm thinking of copper pipes down the fins of the air cooling fins. Which leads to a small pump and a radiator.... Just thinking out aloud for this project of mine. Thanks Link to comment Share on other sites More sharing options...
6538 Posted January 25, 2011 Share Posted January 25, 2011 What'll happen if you water cool an aircooled engine? I'm thinking of copper pipes down the fins of the air cooling fins. Which leads to a small pump and a radiator.... Just thinking out aloud for this project of mine. Thanks Suppose it depends upon what other changes you are making such as restricting the coolling veins to airflow? Link to comment Share on other sites More sharing options...
corevalue Posted January 25, 2011 Share Posted January 25, 2011 How do you propose to join copper pipe to aluminium(?) heat fins with a reasonable thermal performance? Link to comment Share on other sites More sharing options...
athe Posted January 25, 2011 Share Posted January 25, 2011 What'll happen if you water cool an aircooled engine? I'm thinking of copper pipes down the fins of the air cooling fins. Which leads to a small pump and a radiator.... Just thinking out aloud for this project of mine. Thanks You should get increased power I believe. There are kits for converting various specific engines out there - might give you ideas for your project. How are you going to attach the copper to the fins? You'll need good thermal transfer. Brazing with good long fillets would be a good way to go depending on the fin material (aluminium would be hard for instance). You'll need to degrease very thoroughly before connecting one to another. The biggest problem you are likely to have is build up of gunk (eg copper carbonate) in the water system. Ideally the water should only see a single type of metal in the entire circuit. Also be wary of using copper that has a very small bore (2 mm or less). Whilst the heat transfer is better with lots of small pipes, blockages can be a bugger, and if you are getting something like copper carbonate you need concentrated nitric acid to flush it out (which will also eat the pipes). You might want to consider a water substitute like hexid instead. I have successfully converted an air cooled furnace to water cooled. Managed to extract 4.5 kW of heat load (1400C inside) with the outer casing remaining cool enough to touch. No moving parts though so probably an easier project. The heat was wasted through a radiator with a fan. You can get extra flexible copper pipe in coils from the diy stores which is useful for this sort of thing. I seem to recall it was something like 50 or 60 quid for 25 meters. Link to comment Share on other sites More sharing options...
cashinmattress Posted January 25, 2011 Share Posted January 25, 2011 You should get increased power I believe. Well, that all depends on how efficient you make the cooling system. Plus you have to contend with the added mass of coolant + cooling system + the potential air resistance if this is a vehicle + pressurised system + lots more. Steam is a killer. Is this a model aeroplane or something along those lines? Link to comment Share on other sites More sharing options...
athe Posted January 25, 2011 Share Posted January 25, 2011 Well, that all depends on how efficient you make the cooling system. Plus you have to contend with the added mass of coolant + cooling system + the potential air resistance if this is a vehicle + pressurised system + lots more. Steam is a killer. Is this a model aeroplane or something along those lines? Bound to be a motorbike - it's Ken! Link to comment Share on other sites More sharing options...
Rare Bear Posted January 26, 2011 Share Posted January 26, 2011 I can see reasons for wanting water cooling rather than air cooling but why start with an air cooled engine and convert it, why not start with a water cooled engine in the first place? BTW, just as I can see reasons for wanting a liquid cooled engine I can see reasons why one might prefer an air cooled engine. Depends on intended use. Link to comment Share on other sites More sharing options...
ken_ichikawa Posted January 26, 2011 Author Share Posted January 26, 2011 How are you going to attach the copper to the fins? You'll need good thermal transfer. Brazing with good long fillets would be a good way to go depending on the fin material (aluminium would be hard for instance). Finding small copper pipes which are very slightly thinner than the gaps in the cooling vanes, then using thermal paste as in a CPU thermal paste compound to fill in the gaps. Link to comment Share on other sites More sharing options...
OnlyMe Posted January 26, 2011 Share Posted January 26, 2011 Aftermarket oil cooler might be better. Whatever you do to the air circulation with the water cooling will reduce te effectiveness of the air cooling - gain some lose some - not a great design really. Also look to see if you can improve the efficiency of the air cooler - air dams to force more air round the cooling veins, fan or uprated fan / motor would I think all be better and simpler modifications. Link to comment Share on other sites More sharing options...
libspero Posted January 26, 2011 Share Posted January 26, 2011 How will you cool the cooling water? If it just means more air cooling further down the chain it might be a false economy. Just a thought. Link to comment Share on other sites More sharing options...
ken_ichikawa Posted January 26, 2011 Author Share Posted January 26, 2011 How will you cool the cooling water? If it just means more air cooling further down the chain it might be a false economy. Just a thought. With a radiator of course. However I can siphon off the heat for other uses such as this: Proper heated grips! Link to comment Share on other sites More sharing options...
athe Posted January 26, 2011 Share Posted January 26, 2011 Finding small copper pipes which are very slightly thinner than the gaps in the cooling vanes, then using thermal paste as in a CPU thermal paste compound to fill in the gaps. Don't rely on the long term strength of CPU paste in a vibrating environment. You'll need to keep the copper pressed down tight on it somehow. Link to comment Share on other sites More sharing options...
ken_ichikawa Posted January 26, 2011 Author Share Posted January 26, 2011 Don't rely on the long term strength of CPU paste in a vibrating environment. You'll need to keep the copper pressed down tight on it somehow. Hmm looks like a biggish fan with a tapered end in a duct is the best solution then for now. Link to comment Share on other sites More sharing options...
MrPin Posted January 27, 2011 Share Posted January 27, 2011 Hmm looks like a biggish fan with a tapered end in a duct is the best solution then for now. I seem to remember there was a water cooling kit for the old Bonneville many years back! Link to comment Share on other sites More sharing options...
cells Posted January 27, 2011 Share Posted January 27, 2011 Are they not all practically water cooled its just the final heat dump is air. That is to say a chemical mix of mostly water cools the engine and then your radiator gets rid of the heat of the water mix. Adding another water to air heat exchanger will do nothing but dent performance, unless I suppose your second radiator is somehow more efficient or larger but on a bike or car the added weight would make it a bad idea. You can have a direct water cooled engine if it is stationary where you dump the final hot water rather than cool and recirculate but it doesn’t initially sound a good idea on a mobile unit. If you want to use this excess heat for heating something you are better off tapping the line that holds/runs this water chemical mix and taking heat from the liquid rather than the radiator. That’s how cars work. In fact my cars radiator fan is bust and in traffic the engine can heat up as there is no flow to cool the radiator and no fan to force air through. So instead I turn the heater in the car on which promptly cools the engine. That works via tapping into the water mix not trying to recover heat from the radiator. Hope that helps Link to comment Share on other sites More sharing options...
Chicken Posted January 27, 2011 Share Posted January 27, 2011 With a radiator of course. However I can siphon off the heat for other uses such as this: Proper heated grips! Haha - that's magic! Link to comment Share on other sites More sharing options...
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