oil pressure

Mattstrike

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What options are there for increased flow oil pumps?

The setup:
-turbo
-machined crank (10 over on all)
-balance shaft rear oil feed is plugged and drive gear removed for the double roller, balance shaft/bearings left in the block
-oil restricted push rods
-LS lifters
-cam bearings replaced with new, machine shop matched to the cam
-clevite 77 main and rod bearings
-oil filter relocation kit, using an oversized oil filter
-10w30 synthetic oil
-oil volume kit already installed
-oil pressure is being measured at the block main feed (so after all the extra plumbing for the oil filter relocation)

I have a unique oil system setup, I added an electric oil pump because I didn't like the oil pressure I was getting at idle fully heat soaked. This is on a secondary circuit. It has a low pressure check valve that feeds into the primary circuit if the primary circuit pressure falls below the secondary. That valve is before the oil filter so no un-filtered oil gets sent to the block. The secondary circuit currently has a 5 micron bypass filter and a pressure regulator to limit it to 40psi, excess bleeds off back to the oil pan. The secondary system adds 2 quarts to the system capacity between the filter and hoses

The primary circuit drops off to about 10psi at idle. I've seen this on a few other rebuilt 3800's, I'm guessing that's the reason why people don't like rebuilding them. When I plasti-gauged the bearings at rebuild they were within spec. With the secondary circuit on I get 20-30psi at idle, but there's no good reason that the oil pump in the engine can't keep up with idle pressure. But short of getting some sort of video camera inside the engine I have no way of knowing if one of the mains is just gushing out oil or what.

Thoughts? Add a large oil cooler between the filter and the block? Is there an increased capacity pump anywhere? Use 10w40 turbo diesel oil?
 

sickmint79

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i just installed a coolant based oil cooler. although air/air would be needed for more extreme cooling. i'm not sure what "turbo diesel" would mean for your oil but i would expect better hot pressure with 10w40 for sure.

i have my own recent (last weekend) oil journey.



full write up here. Scion FR-S Forum | Subaru BRZ Forum | Toyota 86 GT 86 Forum | AS1 Forum - FT86CLUB - View Single Post - Installed/How-To: 2014 Forester XT OEM Oil Cooler(pics!)

not sure it will help you with anything though.
 

Mattstrike

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It could help as oil pressure is not an issue cold, it's not until heat soaked (engine up to temp for more than 3 minutes) that it starts to drop off.

After sitting for 5 minutes the oil has usually cooled off enough for the idle pressure to go up to about 20.
 

sickmint79

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my oil gauge seems to read higher than the obd2 data. it and pressure are both from a sandwich plate. topping out 4th here, 7500 red line i'm not sure if 7000 or 7500 here, nonetheless my max oil temp for the data per obd2 was 251



on the gauge low 250s is what i recall when looking. at 7k rpm my understanding is you would want 80 psi, i'm at what appears to be 60, on the amsoil 10w30 signature.

interestingly enough another guy observed this:

TRACK TEMPS AFTER 9 LAPS @ 1 Minute 15 Seconds Per Lap
0W20 Redline

0w20 Redline 225F @ 800RPM 7PSI Oil Pressure
0w20 Redline 225F @ 2000RPM 30PSI Oil Pressure
0w20 Redline 225F @ 4000RPM 48PSI Oil Pressure
0w20 Redline 225F @ 7000RPM 43PSI Oil Pressure


10W30 Redline

10w30 Redline 245F @ 800RPM 7PSI Oil Pressure
10w30 Redline 245F @ 2000RPM 35PSI Oil Pressure
10w30 Redline 245F @ 4000RPM 52PSI Oil Pressure
10w30 Redline 245F @ 7000RPM 46PSI Oil Pressure

10W40 Redline (12 Laps)

10w40 Redline 265F @ 800RPM 8PSI Oil Pressure
10w40 Redline 265F @ 2000RPM 31PSI Oil Pressure
10w40 Redline 265F @ 4000RPM 55PSI Oil Pressure
10w40 Redline 265F @ 7000RPM 45PSI Oil Pressure
overall i consider this a resounding endorsement for :amsoil:
 

Turbocharged400sbc

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biggest pressure affector is the wear and tear in the timing cover oil pump pocket.

id hazard a guess at a good bit of slop in there allowing oil to bypass from the pressure to inlet side
 

Mattstrike

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Does a stock oil pressure gauge on these cars compensate for rpm to give a false appearance of higher oil pressure or something?

My worry is that I have a bearing too loose somewhere, bleeding off pressure and having a negative impact on oil supply to the rest of the engine.

I thought I read somewhere that one of the 3800 vendors had a pump with increased volume. I'm kind of at the point where I want to find a belt driven dry sump pump and say fugit.
 

Turbocharged400sbc

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its the later model 5w30 spring, and you can get the same effect with a couple #10 machine screw washers tucked inside the pressure relief piston to bump pressure.

id hazard a guess that its likely a worn front pump housing (timing cover) thtas probably bleeding off pressure to the inlet scroll.
 

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