To Cool, Or Not To Cool

[Skippydiesel]

Nice topic for the Brains Trust.

I am about to repower a Ferris zero turn, with a brand new B&S, 2500, 724 cc, 25 hp engine.
The new engine comes with an oil cooler. The old, same engine, detuned to 23 hp, did not have this feature.

This has got me thinking about my Hustler Super Z, zero turn.
I fitted it with a new Kawasaki FX 730, 726cc, 23.5 hp, only about 80 operating hours ago. At the time I was tempted to fit an oil cooler (bought all the bits) but didn't, feeling that the engine maker would have done this if required.

Our mowers operate in ambient temperatures in the 25-47 degree Centigrade range. I keep them very clean - blowing out any chaff from the engine cooling system, after every use - still I worry about cooling.

What thinks the Brains Trust about installing that oil cooler I have on the shelf????

 

[Tiger Small Engine]

Nice topic for the Brains Trust.

I am about to repower a Ferris zero turn, with a brand new B&S, 2500, 724 cc, 25 hp engine.
The new engine comes with an oil cooler. The old, same engine, detuned to 23 hp, did not have this feature.

This has got me thinking about my Hustler Super Z, zero turn.
I fitted it with a new Kawasaki FX 730, 726cc, 23.5 hp, only about 80 operating hours ago. At the time I was tempted to fit an oil cooler (bought all the bits) but didn't, feeling that the engine maker would have done this if required.

Our mowers operate in ambient temperatures in the 25-47 degree Centigrade range. I keep them very clean - blowing out any chaff from the engine cooling system, after every use - still I worry about cooling.

What thinks the Brains Trust about installing that oil cooler I have on the shelf????

I would think an oil cooler versus no oil cooler would be better.

 

[Bertrrr]

No downside to adding an oil cooler

 

[bertsmobile1]

Check that it has thermostat & bypass
A lot of cheap coolers do not so the oil never gets hot enough to drive out the moisture
Oils are designed specifically to work within a quite narrow temperature range.
Back in the 70's fitting aftermarket oil coolers to motorcycles was all the rage and a lot of them suffered serious damage because the oil never got up to it's operating temperature
I killed several SR 500 Yamahas because of the cheap oil cooler
When I fitted a better one I kept an eye on it and it rarely ever opened except in high summer sitting in city traffic going nowhere .

 

[Skippydiesel]

Check that it has thermostat & bypass
A lot of cheap coolers do not so the oil never gets hot enough to drive out the moisture
Oils are designed specifically to work within a quite narrow temperature range.
Back in the 70's fitting aftermarket oil coolers to motorcycles was all the rage and a lot of them suffered serious damage because the oil never got up to it's operating temperature
I killed several SR 500 Yamahas because of the cheap oil cooler
When I fitted a better one I kept an eye on it and it rarely ever opened except in high summer sitting in city traffic going nowhere .

I doubt that most mower V twins' have an oil thermostat - I have never seen one on a mower engine
You are correct to a point - ideally engine oils should reach over 100 C for a period sufficient to drive of harmful volatiles (water, byproducts of combustion & fuel). Other than this, a crankcase oil that stabilises at, say 90-100 C is running just about right.
Air cooled engines operating in high ambient temperatures (25-47C) should have no problem getting to the above temperatures especially if little grass chaff partially or totally blocks the cooling system.
Without some way to check oil temperature while in operation, I can only speculate, that on occasion the B&S that I am replacing, possibly reached above 120 C for sustained periods - not so good - it threw a con rod.