High oil pressures when cold... Options

[jcwells]

Hello, all...

I'm new to the 914 scene, but have been having a blast reading up on all of the information that is available here at 914world!

I just got my 914 about six weeks ago (details in my signature), and have been able to get answers to a bunch of my questions by pounding on the search button. But here is one that I haven't been able to figure out on my own.

The car is currently running on Brad Penn 20W50 oil, which is highly recommended by Jake Raby and others. Here on the Front Range in Colorado, as the weather has started getting a lot cooler, I've noticed that my oil pressures are quite a bit higher than in warmer conditions. Specifically, with ambient temperatures between 30 and 40 deg, I'm getting better than 120 psi oil pressure at 2500-3000 rpm after running for several minutes. As the oil warms (15 minute commute), it drops to a bit below 100 psi at the same revs. I've got a very efficient front mounted oil cooler, and my oil temperatures rarely get to much more than 200 deg in warm weather, and was maybe 120 deg this morning at the end of my commute. In hot weather, my pressure is just a bit more than 20 psi at idle after extended running, but better than 40 psi after my commute this morning.

Couple of questions:

1. Are my hot weather oil pressures somewhat normal?
2. Are my cooler weather oil pressures too high?
3. Should I switch to the Brad Penn 10W40 now that the weather is cooler?

Go easy on me, I'm a noob... (IMG:style_emoticons/default/smile.gif)

[ME733]

(IMG:style_emoticons/default/popcorn[1].gif) Heres a good rule of thumb, ...10 PSI for every 1000 rpm,s..Years ago some of the riceburner race cars had so much oil pressure that the bearing shells were being pressed into the crank,lifted off the bearing saddles. Premature bearing failure was the result. Excessive oil pressure sucks out horsepower, puts a heck of a strain on the oil-pump-drive tang, causes leaks at the oil filter, and other seal areas in the engine. It was mentioned that you might have aftermarket ..oil pressure relief springs. you probably do. just get and install some O.E.M. oil pressure relief springs.(and compair them to the installed ones.)If you can maintain the oil temperature at or slightly above 212 degrees the moisture in the oil and crankcase will be seperated and vaporized and vented .(a very good thing).You will be removing the primary cause of oxidation,goop and crud buildup in the engine. All the previous comments are valid and excellent. Oil that is too cold will not flow properly, lube the engine or absorb acids and debris and clean it up.I.M.E. (IMG:style_emoticons/default/popcorn[1].gif)

[jcwells]

(IMG:style_emoticons/default/popcorn[1].gif) Heres a good rule of thumb, ...10 PSI for every 1000 rpm,s..
...If you can maintain the oil temperature at or slightly above 212 degrees the moisture in the oil and crankcase will be seperated and vaporized and vented .(a very good thing).You will be removing the primary cause of oxidation,goop and crud buildup in the engine. All the previous comments are valid and excellent. Oil that is too cold will not flow properly, lube the engine or absorb acids and debris and clean it up.I.M.E. (IMG:style_emoticons/default/popcorn[1].gif)

ME733, thanks for the rule of thumb! As an engineer, I love those things.

What you say makes sense. Sounds like whatever we decide to do with the oil, I need to "cripple up" the oil cooling a little bit. I'll have a much closer look at that system tonite, and see if there is a clean way to obstruct the airflow.