shimming oil pressure relief spring?

[JFairman]

Has anyone shimmed the main oil pressure relief valve spring in a 100,000+ mile 1987 930 or 911 motor to try and raise oil pressure around 5-10 psi or somewhere in that area?
Using 20w50 oil.

If so, how thick a shim, washer, or proper sized nut did you use under the spring?

I used to put a 6mm thread size or 10mm wrench size nut inside the hollowed out oil pressure relief piston before sliding in the spring on old single cam 4 and 6 cylinder BMW engines and it worked great for raising hot oil pressure about 5-7 psi.

Is this considered a bad idea on a 911 motor?

[avt007]

It will work the same, but remember, this is a high oil pressure relief valve. It only affects the pressure at high rpm, and will have no effect at idle. Idle pressure is a function of oil pump wear and crank bearing wear.

[cgarr]

Put in some Camshaft Oil Line Restrictors, it bumps up the pressure and keeps the sump less full.

[Rick V]

Arn't cam line restrictors standard equipment on an 87 930?

[JFairman]

thanks for the replies.
just wanted to see if others have done it and i'd like to know how thick a shim they used or recommend.

i've had clogged cam spray bar drama in the past and i don't want to restrict the oil going to the cams and valvetrain, or go through that again.