How to shim your oil pump relieve valve for higher oil pressure

[RussianVR-4]

Originally Posted by MitsubishiSpecialties

Heres an interesting tidbit i wish i would have researched 2 months ago.

91 oem spring = md015988
91 replacement spring = md174687
92+ all springs = md174687

Reason for today's research...........
http://www.3si.org/forum/showthread.php?t=209407

supra guys are 'plagued' by too high of an oil pressure at upper rpms, it basically blows your front main seal out. my buddy's getting tired of replacing them, we're gonna try and see how we can lower the pressure

[mikes2nd]

Originally Posted by RussianVR-4

supra guys are 'plagued' by too high of an oil pressure at upper rpms, it basically blows your front main seal out. my buddy's getting tired of replacing them, we're gonna try and see how we can lower the pressure

yeah thats what I would be worried about "playing around" with shims, adding shims is doing the opposite of what you want to do.

for the 3s...

someone correct me if im thinking wrong here...

assuming you follow the manual and check your "spring" tension and thats right on.

that spring tension is there to basically "limit" upper rpms from causing your oil pressure to blow out of everything..

its functioniong like a bov crank it down and youll get higher pressure at higher rpms...

whats 3 lbs at 2000 rpm and makes your stock gauge look nice and tidy, might be 20 lbs at 6000 rpm... thats bad...

[doctorstupid]

well after doing this and later tearing my engine apart, i can assure you that i did not leak oil out of one single seal with my 2 washers. food for thought

[LRStealth]

Does anyone have any oil pressure numbers before and after shimming?



I'm going to have to take my oil pan off AGAIN because the damn black silicone didn't hold. Switching to red. I'm probably going to try this shim out. My oil pump only has about 5,000 miles on it, but it was installed almost two years ago. No telling when it was actually made.

My current oil pressure is a little low for my comfort:

Hot idle: 9-11 lbs.
2000 RPMs: 25-30 lbs.
3000 RPMs: 35-40 lbs.

I'm also thinking about switching to 50w oil.

[Import Power]

This is definitly something that should not be done blindly. Too high oil pressure, especially going to happen in upper RPMs, can and will be as bad or worse than low oil pressure.

I would replace pump if it is tired, check spring to ensure it is in spec.

[John Monnin]

I made this into a Wikipedia Entry

http://www.3si.org/wiki/index.php/Oi...igher_Pressure

[Ondontii]

i threw about 1/16" of shim in my pump when I installed it a few weeks ago.

But I didnt put thread sealant on the big bolt thing
Oh well.

[John Monnin]

Originally Posted by Ondontii

i threw about 1/16" of shim in my pump when I installed it a few weeks ago.

But I didnt put thread sealant on the big bolt thing
Oh well.

How much did it change your idle pressure?

[Fury]

^ditto, i'll be buying a new oil pump and putting in new rod bearings..curious if its worth shimming up the pump to get better oil pressure?

[92RTTT]

i have seen no increase in idle pressure,and no one else will either. it would only make max pressure higher. you could weld the valve shut and it wont increase idle pressure. it really wont increase hot high rpm pressure much either unless you really shim the crap out of it. id say the valve is mainly useful in cold starts,like when you take off when cold and pressure is really high due to thick oil. when everything is hot, i doubt you are maxing the pump out to the point of opening the valve