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MG MGA - tempeture question

Rather than add to the long list on getting up to tempeture, let me state that there is no such thing as a water cooled engine, engines are air cooled, the water justs transfers the heat to an air flow. The air removes the heat.
As some one has pointed out, fit a radiator blind and be happy.! That is, cut down the air flow.
Restricting water flow will cause heat damage to the exhaust valves and cyl. head. How to check for the correct temp? easy ,if the heater is not reasonably warm the engine is too cool. If you can confortably touch the top tank ,ditto. Engine fan plus an electric fan necessary in hot Aust summer climbing a long hill in third 3 to 4 thousand revs,which equals low air flow , Otherwise the electric fan does the job 95% of the time. I had to refit the engine fan for that 5%. I run a 185 thermostat year round . Runs 185 on a cool day and 195-200 on a hot day. All the British cars up to the fifties used radiator blinds in the winter to bring the temp. up. A piece of carboard will also do the trick. Sean
S Sherry

Without wishing to be pedantic you are incorrect. The engine is water cooled..the water takes the heat away from the engine. The hot water is an intermediate heat transfer medium and in turn is air cooled.via the radiator
..but I agree re the single electric fan...I read the bumf on this site before starting and it did seem marginal...and that is why I fitted twin fans and they manage in all circumstances I have come across so far here in NSW....and I live in very hilly country.
Neil Ferguson

Neil have you ever thought what would happen to the hot water if there was no air flow.? The heat in the water is the portable heat transported from the combustion cycle to the radiator where it is in turn transported away by air flow. Sean
S Sherry

Yes, the engine can be cooled with no air flow, and no radiator. The engine is water cooled. The radiator is air cooled. When the engine is used in a boat it has no radiator and is cooled with ambient water supply. The engine could care less how the heat is removed from the water. The only way you can say the engine is air cooled is if you include the radiator as an integral part of the engine.
Barney Gaylord

Sean, I was quite encouraged by what you said in your original post.
I have recently fitted a thermostatically operated electric fan (Revotec) in order to get rid of that dangerous piece of yellow metal and release the couple of horsepower it was stealing from me. Right now it is pretty cold here and the modified cooling system works beautifully. The engine warms up quickly and yes, the engine is more responsive. I was hoping that the system would cope with our summer, and reading was you said about it coping with the Australian summer 95% of the time makes me think I am in with a chance. I will run with just the electric fan and report my findings on here when we get the right kind of weather to put it to the test.
Lindsay Sampford

Conventional terminology labels internal combustion engines as liquid or air cooled Barney is correct in his statement. Think of the fins on a motorcycle or VW cylinder and head. These are air cooled engines, ie air is the primary cooling medium, oil is secondary. On our MG engines, water is primary, oil and air do assist buy not as significant as water. As I have said before, air cooling of the block is more significant when the differential temp between the block and the external air temperature is large.
Other than that, which is being pedantic, Sean is correct in his description of the use of fans for air flow to help control temperatures on the hot end of things. In other words, cooling the engine compartment on hot days, and not cooling it on cold days are good things to do.
This is great fun!
James Johanski

Barry I think we are splitting hairs here, the subject is an engine with water to carry away the heat and expose it to an air flow. A boat engine has a constant supply of cold water, the expeled hot water disapates the heat to the air. Where does heat go if not into the air ? With global warming and sea tempetures at 190% these boat engines are going to be in trouble ! Outside of all the technical reasons our MGAs overheating , if there is not enough air flow they get hot and too cold if there is too much air carring away the heat too quickly.
To our friends with cool runing engines reduce the air flow as Domonic has done in sunny Switzerland. In good faith , Sean
S Sherry

This thread was discussed between 22/12/2010 and 24/12/2010

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