Max Engine Oil Temp

[creynolds]

Just curious what most people feel is a safe maximum engine oil temp. We usually see around 255 deg at it's hottest point. Personally I think it should be ok up to about 270 degrees but would definitely like some opinions. We're running a single PWR oil cooler with electric fan on a 408 SBF that's making around 550HP. Currently using Royal Purple synthetic oil but may switch to Red Line in the near future. The rep from Royal Purple was absolutely no help in suggesting a safe limit. He side stepped the quesiton in every way possible because he didn't have the answer. Most people I've talked to either don't monitor oil temp or don't know. What are most of you seeing in the desert in a race condition?

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[Co-Dog]

It's tough to get a straight answer from anybody. Temp. is pretty simple with standard oil, anything above 230 and it starts breaking down. Oil loses its ability to maintain viscosity when it breaks down. Keep an eye on the oil pressure. As the oil reaches its breakdown point there will be a noticeable drop in oil pressure.

I have been told that 280 is tops for synthetic. Chances are you've got bigger problems to deal with at the point that your oil is getting that hot, so maybe temp. for synthetics is a moot point.

[John F2000]

I think 250-280 is ok.

[Wendell #527]

In my air cooled type 4 motor I'm OK at 220 (measured going into the motor from the cooler) but I've lost a motor when it was 240. I have a Fluidyne cooler and I'm guessing the temp was 280-290 coming out of the motor at that time. Normally mine runs at 160 now.

[Ziggy]

Max oil temps vary from application to application.
What you really need to watch for is a 10 degree or higher increase in oil temp.This is usually a good indication that something is wrong.
This is not to be confused with the water temp as it can vary greatly.

[Red Line Oil]

Some products are far more stable than others. You didn't list what actually viscosity that you are using, so its hard to tell what's going on. The fact that you are checking motor oil temp is the first battle, as relatively few teams are watching it closely.

Dry sump or wet sump?

We have customers that run the oils well above 280, but it's not something we recommend. You should be aiming to run around 220 to 230f. If you get toward 240 or 250, you look into how its being cooled. 260 or 270? You need to make some changes, in our eyes.

Again, I don't know what you're using, If you're going to look into Red Line, you should start with our 40WT Race. It's an ester-based 15W40 multigrade with lots of antiwear (ZDDP). Remember that going heavier isn't always best when trying to lower its temps, as a thicker fluid can trap heat.

Also considering a way to vent heat out from under the hood. That can make a dramatic drop in oil temp.

Hope that helps,
Cameron Evans
Red Line Oil

[creynolds]

Thanks for all the input guys. We're running a 20W50 oil and it's cooling through a single PWR cooler with fan (~10"X14"). We've got another oil cooler on order that's substantially larger (14"X22"). I spoke with Amsoil the other day as we were considering their oil also and their rep told me that for continuous use they recommended not going above 220deg. He said it would handle higher temps for short periods of time.

Cameron, I'm assuming the 40WT your suggesting has a really high Zinc content, is that right? Lot's of Zinc is good in our applications right? Thanks for your help.

[hoeker]

RP is the best oil available hands down, you can look at others but will be stepping back.

the rule of thumb i've always heard was that every 20 deg of temp over 240 cuts the life in half, at that rate it doesn't take long to be a problem.

heavier oils handle higher heat better than others but as redline said they don't let go of it either, i am one of the few racers running 40wt oil in a pro-2, it works great, saves me HP, and runs cool with one setrab cooler. we don't even change the oil every weekend like many teams feel they "have to"

are you running the RP racing oil? its much better than the regular 10-40 synthetic.

[creynolds]

Yes Ross, we're running the RP Racing Synthetic, not the standard off the shelf RP. With the addition of the new cooler I think our problems will be solved. Although my brother has created a few more problems after playing B-52 Bomber. He nose dived it this weekend and couldn't pull up in time!! The truck plowed on the front skid plate and snapped rolled to it's lid. Oh well, at least the cherry has been popped! Thanks for the help.

[Jerry]

When I had my truck with a patton 442 we ran his special oil from Neo. I was worried about the same thing, oil temp. He told me I was good till 300. That was with Dry sump and his speacial oil. It seems to me that we were always around 270 give or take 10 to 15 degrees. Hope that helps.