74 911 high oil pressure

[EVOCN]

Good afternoon

I have a 74 911 standard coupe with a 2.7. The engine was rebuilt about 6000 miles ago. It has recently been parked and garaged for about a month due to a windshield water leak that's now fixed.
Since I started driving it again, I noticed that my oil pressure reading is consistently around the 100psi mark around 3000rpm's. It does fluxuate slightly higher or lower with the higher or lower rpms. Before parking it the reading used to
be around the 50-60psi. I currently use a 20w-50 oil. Can you offer me some suggestions as to the possible cause and repairs.

Thanks in advance

D. A. Keena
EVOCN

[Tyson Schmidt]

I seriously doubt that the gauge is accurate. I think you have a faulty ground somewhere. Check the chassis-to-trans. ground strap first. Replace it if it even "looks" old. It's a common failure point.

An easy way to check the wiring and the gauge, is to remove the wire from the sender and touch it to ground on the engine. The gauge should read zero. With the wire to the sender disconnected and not touching anything, the gauge should peg full.

If the gauge doesn't go all the way down to zero when you touch it to ground, then you have excessive resistance in the ground path somewhere, due to a poor connection, corrosion, or built up resistance in the wiring.

If it passes the above test, the sender is likely bad.

[rob911]

mmmmm...

pressure sending unit bad?

see http://www.pelicanparts.com/cgi-bin/vb/showthread.php?s=&threadid=54596&highlight=oil+pressure+high

masraum entry

lots of other threads searching for "oil pressure high"

good luck

[Leland Pate]

I would agree that it is most likely a guage or sender malfunction.
The sneder is cheap and very easy to replace.
I'm going to leave this to the more P-technically inclined (Warren), is there a chance that the oil pressure relief bypass pistons and springs have stuck?

Probably a sender though.

[Roland Kunz]

Hello

is there a chance that the oil pressure relief bypass pistons and springs have stuck?

Yes but it sounds more like the sebder. Just tap it slightly and see if it will affect the readings.

Grüsse