Im just curious as to what people think this might be.
Cheers
Lee
Depends on the oil used.
From memory mineral oil will break down before synthetics, but unless its Royal Purple it might cause problems in a rotary.
Fish
Yeah Im aware of that, but what sort of figures are we likely to be talking.
I need to weigh up my options on how much im going to need to do to make the car ok for track, and oil temp would be a concern.
Lee
I\'d like to know this just outta curiosity???
Its very hard to give accurate details as it depends on so many things, how old the old is, make and quality, how long sustained at a given temp. It may be fine at 105 degrees but for only a short time. Maybe fine at 100 degrees but not for a track day.
But approx, ball park, average mineral oil will start to break down at 105-110 degrees, it loses its visoscity and starts become watery to the touch. Fully synthetic will be fine at temps above 120-130 degrees quiet comfortably.
All healey racing cars are now using royal purple because of there protective properties and these are old classics, after 2 years the oils was drained and was still clean and in good condition when tested. There is also a guy how has raced his M3 for 2 seasons on royal purple and again clean and still in good quality.
http://www.hannibalrx7.co.uk/acatalog/Royal_Purple_Oils.html