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2G Quick oil pressure question

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Sam's GSX

5+ Year Contributor
394
54
Jun 10, 2018
Hohenwald, Tennessee
I know questions like this have been asked a thousand time, I figured itd be easier to to post my exact situation and hopefully get a quick answer.

(Mostly checking if my oil pressure is too high)
Right now its around 90psi on the highway fully wormed up (4000rpm), 20psi at idle (1050rpm)
If I get into boost, the gauge goes up to 100psi (which is the most it reads, it's an electrical glowshift off the ofh)
So its probably more than that, but I cant tell.

My setup: bearing clearance is .0025 on all.
Stm balance shaft delete.
Oil squirters blocked off.
4an feed and 10an drain for turbo.
Running 20w50 VR1 non synthetic
(I believe that's everything that effects the oil, but if you think of a question let me know)

I'm not sure if I have the option to go to a thinner oil, that is if this oil pressure is a problem.

Any help is appreciated, thank you
 
That's about where my circle track car runs and my set-up is about the same. My warmed up pressure is a little lower but cold start and a few RPM gives me about 120psi. I'm running delo 15w40 non-synthetic which is a little thinner than what your running. I'm also probably getting my engine hotter so makes sense that your pressure is a little higher that what I see.

If you don't want to go to thinner oil and you'd like the pressure lower your only real option would be to port the relief valve on the OFH. It's pretty simple to do. Altho you have to remove the timing cover to do it. You could also change to a different OFH. Different ones give different relief pressures. Jafromobile has a video on youtube that goes over which ones give what pressures.
 
Ok great, thanks for the info, I'll look into the oil you're running and see if it will work for me.
I have seen people port the ofh, I dont have a problem running that high pressure, mostly because I'm not positive of the potential problems with it, it's a freshly built engine so it has all new seals.
the oil pump itself is used mostly because i didn't want to go through a hassle priming it.
(I did add oil to the chra right before first crank, and i cranked it for 15 seconds before attempting to start it)
 
I know questions like this have been asked a thousand time, I figured itd be easier to to post my exact situation and hopefully get a quick answer.

(Mostly checking if my oil pressure is too high)
Right now its around 90psi on the highway fully wormed up (4000rpm), 20psi at idle (1050rpm)
If I get into boost, the gauge goes up to 100psi (which is the most it reads, it's an electrical glowshift off the ofh)
So its probably more than that, but I cant tell.

My setup: bearing clearance is .0025 on all.
Stm balance shaft delete.
Oil squirters blocked off.
4an feed and 10an drain for turbo.
Running 20w50 VR1 non synthetic
(I believe that's everything that effects the oil, but if you think of a question let me know)

I'm not sure if I have the option to go to a thinner oil, that is if this oil pressure is a problem.

Any help is appreciated, thank you
If the OFH is not ported and if the oil pressure relief valve is operating smoothly as it should, that number is quite normal with blocking balance shafts oil feed holes and oil squirters. You are probably having a steady oil pressure around 100 psi. and you have 100-120 psi spikes by revving up but it should be settled to around 100 psi instantly. It's kind of high side but not too high, you wouldn't probably have any issue. I used to have those pressure numbers for many years but I never had any issue.
In case if you want to lower the max oil pressure, porting the OFH have been the most popular method but personally I am not a big fan of porting the OFH, so I shim the oil pressure relief valve plug. Shimming would also be able to lower the max oil pressure and also would make the spikes lower. I don't have balance shafts, oil squirters neither. I even have a narrower oil main passage in block, plus a bit tighter pump gears/stub shaft clearance. Those should be making the max oil pressure higher but my steady max oil pressure is around 80 psi at 200°F oil temp without porting the OFH, just by shimming. In my recent setup, adding two OEM aluminum oil pressure relief valve washers made the max oil pressure around 20 psi lower. (So it has 3 washers in total and that's about max due to the number of remaining threads). Maybe better try before removing the OFH in case if you want it lower. If it would work for you, you would have less of a hassle.
Just make sure the oil pressure relief valve's plunger slides smoothly, that's very important.
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WOW MAN, thanks for the write up!!!
This puts me at ease, because if I want to lower it next oil change, I can pretty easily from the looks of it.

Thanks so much man.
 
If the OFH is not ported and if the oil pressure relief valve is operating smoothly as it should, that number is quite normal with blocking balance shafts oil feed holes and oil squirters. You are probably having a steady oil pressure around 100 psi. and you have 100-120 psi spikes by revving up but it should be settled to around 100 psi instantly. It's kind of high side but not too high, you wouldn't probably have any issue. I used to have those pressure numbers for many years but I never had any issue.
In case if you want to lower the max oil pressure, porting the OFH have been the most popular method but personally I am not a big fan of porting the OFH, so I shim the oil pressure relief valve plug. Shimming would also be able to lower the max oil pressure and also would make the spikes lower. I don't have balance shaft, oil squirters neither. I even have a narrower oil main passage in block, plus a bit tighter pump gears/stub shaft clearance. Those should be making the max oil pressure higher but my max oil pressure is around 80 psi at 200°F oil temp without porting the OFH, just by shimming. In my recent setup, adding two OEM aluminum oil pressure relief valve washers made the max oil pressure around 20 psi lower. (So it has 3 washers in total and that's about max due to the number of remaining threads). Maybe better try before removing the OFH in case if you want it lower. If it would work for you, you would have less of a hassle.
Just make sure the oil pressure relief valve's plunger slides smoothly, that's very important.
You must be logged in to view this image or video.

That's a great way to adjust the pressure without removing the OFH. Have I been under a rock or is this new to everyone else? Have you had any issues with oil dripping between the washers? This info is great! Thanks for the christmas present of great information! @DSMPT
 
Have I been under a rock or is this new to everyone else? Have you had any issues with oil dripping between the washers?
I don't think it's very new but since porting the OFH actually works well and it has been a common standard for DSMers since long time ago, so I guess not so many people have even thought going with another way and have actually tried it.
I have never seen oil coming out between the washers. I apply a little bit of Ultra Grey RTV on the washers though.
 
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