Hi Matt,

Well sir,.......I'm not sure that applies across the board to all oils; mineral, glycol-based or ester-based synthetics.

Like people, some oils are better than others and 280+ deg F isn't an issue for top-rated oils such as Motul 300V.

While power losses are evident when oil temps reach that high, one should not experience problems if a real high quality product is used and I always recommend speaking to the people who make what you are using. Certainly, engine clearances also affect whats tolerable, as well.

Here's an example; many years ago I recounted a story on Rennlist about an experience I had with the (old) Mobil 1 15w-50 in a 911 racecar that ran without a fan for over an hour in 95 degree temperatures. The oil temp gauge was pinned above 310 deg F for that period and upon engine disassembly, no issues were found. While the crazy temps didn't help performance (he won his race), the characteristics of the product you use helps determine whats safe and what isn't.

 

I'm not saying I'm right, just what I remember from talking to Shell engineers at PRI. I'll try and give them a call tomorrow and see what they say.

Now, you may have had someone run 310 degrees for an hour, but exceptions don't make a rule. Regardless of whose oil is in it, that is higher than I would let one of my engines run.

 

Thanks for all the input guys. It really helps hearing from everyone's experience.

 

I should have mentioned as Steve noted that those temperatures were with high quality synthetic race oils. Upon disassembly for rod bearings there was no evidence of burner oil or scorched bore or bearing surfaces. It all looked fine.

The other thing to note is that a 911 motor is air/oil cooled, without the added capacity of water cooling I wouldn't run a 911 into those ranges. 260 would be about the point I'd be backing out of it. The 996 motor? Not so sure, my tendency is to treat it like a 911 even though it is predominately water cooled. Maybe the value of the engine comes into play, but it is a limitation of the engine not the oil.

 

Matt,

I didn't say that it was a rule or even acceptable: my point was only to caution anyone about making generalizations about oils and maximum acceptable temperatures. The example I wrote about was due to an accident where the driver missed a shift and tossed the fan belt; it was not by design.

We go to great lengths to make certain that our air-cooled race cars (and street cars) never exceed 210 deg F, however the engine and its lubricant should be able to handle more, if necessary.

The water-cooled Cup engines are happy at 220 deg F: water & oil and that's where we run them.

 

can anybody chime in to tell me how they get oil temp on their 996.2 ?

any iphone app or something ? I have the durametric but i can't run session with the laptop on my laps