robski

Some good stuff going on in the number 3 bigend thread, so I didnt want to start this one there.

Question : why do we have both oil and water doing a cooling job in the engine.
Obviously oil is there primarily to keep metal parts apart, and provides the cooling as an extra.

However, Im interested in what proportion of cooling the oil is supposed to provide? Is it SUPPOSED to provide any?

Also, does the water jacket provide enough cooling in its own right to keep the engine within operating parameters? (i.e. assuming the oil doesnt do any cooling, but keeps components well lubed)

Does the scoob have an "oil to water" or an "oil to air" oil cooler?

Why? Well I was wondering whether it would be worth running the engine a tad cooler by using a slightly lower temp ranged thermostat. Or is it the case that the cooling system would be open all the time anyway when running at reasonable speeds?

I am assuming that the ability of water to remove the heat from the engine would be sufficient, and that this would allow the oil to better do its primary job of providing the lubrication rather than helping with the cooling.

Ready to be shot down in flames

robski

chiark

The scoob has a doughnut oil to water heat exchanger which has the effect of warming your oil quicker when cold, and taking away heat from the oil when up to operating temperature.

It takes a hell of a long while for oil to get up to temperature (like 10 mins minimum)

I don't think, but likewise have flame suit on, that oil provides great cooling.

Adam M

Oil must provide some cooling otherwise they aouldnt have oil squirters which directly cool the piston from underneath.

Water is used to cool the block down, but it doesn't actually directly cool the pistons, which must surely get hotter than any other part of the engine as they do not have substancial mass to conduct and radiate the heat away and are not in contact with cooling water in the same way as teh block is, therefore I can only assume that any cooling they receive is through direct contact with oil.

Obviously the lubrication properties of the oil are most important too.

Sam Elassar

i thought oil stopped the oil squirters since MY95-96 so it couldn't have been a good idea.?

sam

MorayMackenzie

robski,

Oil does contribute to engine cooling... it's part of it's function. It also has to absorb and hold byproducts of the combustion process, which is mostly why it goes black and requires regular replacement, mostly.

Adam,

Not all engines have oil-squirters under the pistons.

Moray

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moved to drivetrain