924Board.org

[geddes66]

My son has and old 924. Its oil pressure is lower than it should be. (obviously)I am running 15-50 synthetic. The oil pressure is very high prior to warm up (8/9bar). I noticed that the oil filter is within 1/2" of the header.

Could the proximity of the oil filter to the header be rasing the oil temp higher, high enough that the tempuature is causing it to thin? Thus dropping the pressure. Would adding a remote filter (and/or oil cooler) help enough to use a thinner viscosity oil and relive the high pressure spikes when cool?

Thanks all
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The Porsche is now my son's, my car is cooler, slower but cooler.

[Ozzie]

My car when cold runs about the same.
When hot it runs about 2 bar at idle.
My question to you is -- is your guage or sender accurate?
Poor earthing or bad senders will give you anxiety when none is warranted.

Are you relying on the oil guage alone or have you some other means of pressure testing?
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Porsche 924 1984 (UK import) NA
Its AUTO and its BLACK
Montego Black on black/red
Engineer of Electro/Mechanical Systems Maintenance

[D Hook]

What's the pressure when the engine is warmed up? Should be around 2 bar at idle, IIRC.
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'80 924 n/a SOLD

[geddes66]

I am assumeing the guage is accurate. It reads high when it should be and low when you would expect. At idle it usually has the light on, so it is less that 2. It has been posted that the light on at idle is ok as long as there is the correct amount of oil flowing. It is around 4 bar when at speed.

Iwould simply assume it is worn out but the pressure is so high when cold that I started thinking it may be the temp.
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The Porsche is now my son's, my car is cooler, slower but cooler.

[Paul]

What is your idle speed and engine temp when the light comes on? Also have you cleaned your pressure relief valve?
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White 87 924S "Ghost"
Silver 98 986 3.6l 320 HP "Frank N Stein"
White 01 986 "Christine"
Polar Silver 02 996TT. "Turbo"
Owned and repaired 924s since 1977
Porsche: It's not driving, it's therapy.

[John Brown]

Since you mentioned a header I assume you have an aftermarket header which indeed is VERY close to the filter. And the header allows more heat into the area by far than the stock manifold and downpipe.

These cars tend to run hot oil temps anyway. The header could exacerbate that tendency. I always wrap the header. Yes, it causes the header perhaps to die sooner. But overall it's better for the complete assembly under the hood!

Somewhere on the main site is a reference for shorter filters that provide more clearance to the header.

Since you are in southern CA consider using a single weight oil. I'd start with 40W in your climate. Valvoline makes a 'race' oil in single weights. Since it (apparently) does not have all the additives of a standard street oil it needs to be changed more frequently. Synthetic is nice and I use it in the turbo. But for an straight 924 in your situation consider 'plain dino' and more frequent changes. If nothing else it would be an interesting, and cheap, experiment to see what happens to the pressure.

The use of an oil cooler would be good but far more work than is needed I think for a street car. Proper installation is a pain. There ain't much space in there as you know.

How many miles on the motor?
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John
80 931 - #931 44Cup
99 Escalade - tows track cars
gone but not forgotten: original 924.org car - 82

[geddes66]

Engine RPM 800-1100 when light comes on. Temp reading not quite straight up. Miles are unknown as the Odometer is broke. (What a surprise) I started using synthetic oil because it has the lowes "cold" viscosity number (15) for the "hot" number (50).
The reason I was thinking cooler is I have a remote filter and a 11X12 oil cooler laying around already. Hadn't thought about wrapping the header though that is a great idea. It is so close that changing the filter is very difficult. Going remote/cooler fixes that also.
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The Porsche is now my son's, my car is cooler, slower but cooler.

[John Brown]

[924RACR]

The oil will run hot regardless of header config - not so much heat transfer when driving. As John noted, they run hot regardless. I've raced with the stock manifold, same problem.

For racing or track use, there's no question you'd want an oil cooler; for street use it's usually enough to just run synthetic.

The light comes on about 0.5bar, BTW. As long as it's only at hot idle, not a big deal, but synthetic's resistant to viscosity loss at high temps helps avoid this.

John's right about the Valvoline too - I've actually been running that (last season) in my racecar, and combined with a good cooler (8x11 for me) it'll handle any heat and doesn't thin out. IIRC I've been using the non-synthetic Valvoline VR1 40W oil. I have to pull my pan and check out the rod bearings soon, before this season starts, before I can really give it a 100% pass rating.
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Vaughan Scott
Webmeister
'79 924 #77 SCCA H Prod racecar
'82 931 Plat. Silver
#25 Hidari Firefly P2 sports prototype

[Blas]

If you cut open the standard oil filter, you will see a discoloration on the inside of the filter that suggests oil was "toasted" at the bottom side of the filter closest to the header....I made the switch to a shorter filter a couple years back and that seems to have eliminated the problem, or at least the perception of a problem...
From the tech section:
"...Use a shorter filter: Fram PH3614 or Pennzoil PZ21 or equivalent. These are about 1 1/2 inches shorter..."
If you run a cooler on the street, you should have a thermostatic bypass installed around the cooler. Oil needs to get hot to work properly...light driving on cool days can actually do more damage by preventing the oil from maintaining the proper temperature....thus not flowing properly...