oil temperature rises too high

[tinhat]

Running my 1990 ZR1 on a road track. The oil temparture rises so high it reduces the rpm's. After a 10 minute idle then shutting the car off then on it will be good for a few laps. Any idead on how I solve this?

[Marc Haibeck]

Are you running the engine over 6000 rpm for more than a few seconds at a time? The water pump cavitates and stops pumping over 6000 rpm engine speed. When the coolant stops flowing the oil absorbs all of the engine heat and overwhelms the oil cooler’s heat exchange capacity. You can go over 6000 rpm for a short time to wind through a gear or to pass, but keep the time over 6000 rpm to only a few seconds at a time.

The cavitation speed can be increased to 6250 rpm with an oversize water pump pulley. If an undersize crankshaft pulley is also used the cavitation speed will increase to 7400 rpm. Beyond the rev limit. Unfortunately, the engine needs to be removed to install an ATI damper with an underdrive pulley. Pete has the pulleys.

Marc

[tinhat]

Marc, I think you are right since it did not overheat every time. The oil temperature overheating happened when I was in the heat of the moment and driving hard. I'll keep it below 6,000 rpm net race. Thank you.

Jim

[LGAFF]

Guy with a TT Ferrari 348 had the same issue, an impellar redesign solved the issue.