Thread: Average engine temps

Originally Posted by josh.huber

https://www.haydenauto.com/media/567...ts_6980012.pdf

Pretty good read on how they work and vary the speed

Absolutely brilliant thanks

Originally Posted by josh.huber

Yeah oils ain't oils, how do the mineral oils perform as far as lubricity at higher temps? Besides losing viscosity I thought it was the main risk. As they may maintain enough viscosity for pressure but will not be able to reduce friction in moving parts.

For most moving parts in an engine they are relying on a hydrodynamic oil film - in general as long as that film is maintained then there should be no contact of the moving parts. The higher the temp then the film strength of the oil will drop off and possibly cause contact between moving parts. The piston rings however rely on boundary lubrication which is more a function of the additives added to the oil rather than the oil itself.
In short there is no simple answer to mineral vs synthetic - there are some really good mineral oils out there and there's also some really crappy synthetics as well. If you really want to pickle your brain over it, google rat540 oil and have a read of that dudes blog. Lots of good info there