Approximish spacers needed to increase oil pressure?

Started by Turbodave, June 04, 2018, 08:20:36 PM

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Turbodave

I'm using the ball & spring, and seem to be maxing out at 50psi cold, which ends up at 25psi when piping hot. I think it's time to put a little more pressure in the old girl. Is there an approx spacer/psi relationship, or can I work on assumption of if I have (for example) 0.5" of spring compression and have 50psi then 0.6" of compression (0.1" spacer) will give approx 10psi more? (This seems to make sense)...
I don't mind trial and error, but if someone has been there before, and knows the answer, I'd appreciate it.

Cheers!

MiniDave

I had the opposite problem anytime I used the ball and spring set up, it pegged my oil pressure gauge at 100 psi, I tired cutting off one coil but it didn't make any difference so I gave it up.

No idea if it's a linear pressure with the length of the spring, I'd say put in the spacer and see what happens.....keep adding till you're happy. But I think I would try the stock spring and plunger to see what pressure you get with them first. When I couldn't get the ball to work I put a new plunger and spring in mine and it cured my low pressure readings.

Is your 50lbs at 3K rpm or idle?
Complete failure at retirement

1989 Cooper Racing Green
2009 Clubman S
2014 Audi Allroad

jedduh01

I would consider jumping straight to a directly adjustable unit. 
To me the back and forth on the 'shims would drive me nuts!


https://www.7ent.com/products/oil-relief-valve-adjustable-for014.html 

also can ' drill + tap + make your own...


croc7

I've read that use of the ball could deform the plunger seat and cause oil pressure fluctuation.  Others have said they've used the ball and spring for years with no trouble, so the choice would be yours.  I stayed with the plunger and spring.  To raise oil pressure, compress the spring by placing an appropriate size washer inside the domed oil pressure nut.  Or buy a new plunger, lapping it in the seat and install a Cooper S spring which is rated at 70 PSI.  If the result is oil pressure that is too high, install a copper washer/s between the domed nut and the engine block to effectively lengthen the spring.  Good luck.  Let us know the results.

MiniDave

I found those adjustable oil pressure thingies to be of less than stellar quality, I'd go with Croc's recommendations. But, I wonder if the issue is a worn engine rather than a weak spring - that's why I went with a new spring and plunger - to be sure.....my results were good fortunately.
Complete failure at retirement

1989 Cooper Racing Green
2009 Clubman S
2014 Audi Allroad

Turbodave

#5
Can't use adjustable unit as I have an intercooler pipe about 3/8" forward of standard cap.
This is also why I was wondering if anyone had real life experiences of the spring force/displacement as it's a royal PITA to get in there. I'll baseline my current spring force at seating, spring compression at seating, spring rate, and the oil pressure attained, and then do a few tests to correlate the math for an increased spring force.


croc7

I looked at my notes from a couple of years ago when I was fiddling with high oil pressure and shortening the free length of the spring by 0.1" = 10#s pressure drop.  Don't know if the inverse is true.  And with a stated clearance 3/8" of between the dome nut and an inter-cooler pipe on your engine, I don't think that the adjustable oil pressure valve would fit-the knurled adjustment knob of the valve would interfere with the inter cooler pipe.

MiniDave

Croc, I took one coil off the spring when I was trying to get the ball style pressure regulator to work, still showed 100 psi or more cold (my gauge was pegged)

That's when I decided to go back to the stock spring and plunger. Mine now shows 70 cold, 60 hot at 2500 rpm and above.
Complete failure at retirement

1989 Cooper Racing Green
2009 Clubman S
2014 Audi Allroad

croc7

I had oil seeping/leaking/oozing/weeping from the lock nut threads of my adjustable oil pressure thingy.  Solved it by sealing the threads with the Toyota product FIPG.

Turbodave

Well, I figured I give you guys an update.

I pulled the spring out of my engine, and realised it had a plunger in there, not a ball. I built the engine less than 11 months ago and I'd completely forgotten.
Looking through my past build notes,  I actually got rid of the ball many years ago because of the weird fluctuating pressure ( that's what my notes say at least ).
Luckily I have a stockpile of stock engines, so went and pulled a spring from one of them, and at some point, I obviously shortened the spring as my original spring was 1/2" shorter than another A+ spring.
I just went ahead and put the stock A+ spring in my engine, and got 60psi immediately.  I couldn't run it up to temperature because I didn't have any coolant in it at the time, but I'll report back.

croc7

Were you able to solve your low oil pressure problem?

Turbodave

Well yes!
The factory plunger and factory (used) spring provides 50psi cold (or as cold can be expected at this time of year!) and 35 psi when super hot (as can be expected at this time of year) at 950 rpm. Remember though that although I'm running the "high capacity" turbo pump, I'm feeding the 16v head (that needs more volume flow than the rocker shaft of the 5-port), the turbo, and the piston cooling jets - all of which consume valuable oil flow at the low RPMs.