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Old 07-28-2015, 06:33 AM   #1
Fyeganeh
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Join Date: Feb 2015
Location: Baltimore, MD
Posts: 60
Oil Pressure - Changing a Piston

I found this on an oil starvation thread on the racing section and posted a comment there - but given that people don't read that as much, I am cross posting over here to get people's opinion on this "maintenance" item...

Quote:
Originally Posted by insite View Post
another note on oil starvation:

there is a piston/spring assembly inside the oil pump that varies oil pressure with temperature. when the car is cold, it's designed to increase the pressure to around 100psi. once the car warms up, it backs off to 'normal'.

my car was running about 16-17psi (hot) at idle, which seems low to me. on a hunch, i ordered a new piston & spring. interestingly, the new piston has a chamfered edge whereas the original piston had a sharp edge. this leads me to believe that porsche suspected some binding of the piston assembly in some instances......

at any rate, with the new piston / spring installed, the car is now at 23psi hot. i never logged the oil pressure under load, so i have no idea what (if any) effect it has on pressure at RPM, but i certainly feel a little better. loss of oil pressure at temp is a big concern in the M96. anything that reduces the risk to that end is a win in my book. cost is less than $20 and you can do it in 5 minutes when you change your oil.

FYI, part numbers are:

Piston: 997.107.125.01 ($ 5.00)
Spring: 996.107.127.53 ($10.00)
Gasket: 996.107.123.50 ($ 2.00)

End Quote

So I know this is an old thread, but I was wondering about people's opinion on doing this "upgrade" or refresh on an oil pump piston, spring and gasket. Has anyone tried this? Did it help? If you haven't done it, what is the consensus on doing it? Could it hurt?

Any thoughts would be appreciated.
Fred
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