Low oil pressure???

S

Sleeper1987

3.8L of Fun!
Joined
Jun 11, 2006
got about 7-9 psi hot idle pressure 15w40 shell rotella and 10 psi per thou till i run it down the interstate for a while then it creeps down to 20 psi at 3,000 rpm. I installed a new oil pump gearset and had the adapter surface cleaned up so the was no grooves. Added the 70 psi spring in the melling kit, tryed the 60 and the 40 psi springs with no differance. It has the biggie oil filter kit with the large diesel suburban filter and long oil lines to a mount in the old battery location. they have a 5/16 oil line ran to the turbo from the oil filter mount. i added a .080 restrictor to it with no pressure change.

so heres the basic rundown

oil has about 200 miles since changed 15w40 shell rotella

ac delco oil filter on remote mount 3/4 oil lines to and from

new oil pump gears and gasket

new relief spring.

no smoke rattles or knocks.

7-9 psi hot at idle

around 20 psi @3,000

can free rev it and it has 10 psi per 1,000 but not with load.


Any ideas? maybe go back to a stock filter?
 
pressure

sounds like my engine. My plans are to run it till it dies. Most people probably have the low oil pressure issue also, from many i've heard its an inherrited issue. If you scared, pop the pressure gauge off. :smile:
 
TURBOELKY said:
sounds like my engine. My plans are to run it till it dies. Most people probably have the low oil pressure issue also, from many i've heard its an inherrited issue. If you scared, pop the pressure gauge off. :smile:
Click to expand...


It's not that im scared, Im just looking for the few extra psi it would take for me to feel good about it. id like to see 15 hot idle
 
Check the gears' end clearance. I changed a .012 thick gasket to a .007 thick gasket which increased my oil pressure from 9psi @ idle to 17psi. If I remember correctly the gear clearance should be .002 - .004.
 
Lee Thompson said:
Add a larger remote after market oil cooler.
Click to expand...



You know i keep seeing this everywere that the biggie kit and big oil coolers add pressure,I dont understand how adding more line area how it would help pressure on a system that already has a weak oil system.
 
slipstick said:
Check the gears' end clearance. I changed a .012 thick gasket to a .007 thick gasket which increased my oil pressure from 9psi @ idle to 17psi. If I remember correctly the gear clearance should be .002 - .004.
Click to expand...


Im going to pick up a thrust plate today i belive thesecome with the differant thickness gaskets correct? The melling oil pump kit i bought only had one for the cover last night
 
I suspect you have internal issues. But by blueprinting your front cover, you can rule out the pump as the source of the problem.

The iron thrust plate is a good idea and an adjustable oil pressure relief valve setup is a good idea too.

Mike at TA Performance sells a gasket set of different thicknesses to adjust your end play on the gears.

Take the front cover OFF the engine and rework the oil passages as outlined in the Buick Motorsports book. The oil makes several 90 degree sharp turns on both the pressure and suction side of the pump. This drops oil pressure and makes the pump less efficient. Follow all the instructions and keep clearances to a minimum.

If you still have low oil pressure, you have internal hemmoraging (bearing clearance issues).

Just as a comparison, My engine runs some looser clearances (.002 rod & .0025 mains). I am using a stock reworked front cover with 10W-30. I maintain 15-20 psi at a hot idle and I regulate pressure to 75psi above 4000 RPM and I measure oil pressure at the back of the engine.

Let me know if you need help with the instruction from the BMS book.

Dave
 
turbodave231 said:
I suspect you have internal issues. But by blueprinting your front cover, you can rule out the pump as the source of the problem.

The iron thrust plate is a good idea and an adjustable oil pressure relief valve setup is a good idea too.

Mike at TA Performance sells a gasket set of different thicknesses to adjust your end play on the gears.

Take the front cover OFF the engine and rework the oil passages as outlined in the Buick Motorsports book. The oil makes several 90 degree sharp turns on both the pressure and suction side of the pump. This drops oil pressure and makes the pump less efficient. Follow all the instructions and keep clearances to a minimum.

If you still have low oil pressure, you have internal hemmoraging (bearing clearance issues).

Just as a comparison, My engine runs some looser clearances (.002 rod & .0025 mains). I am using a stock reworked front cover with 10W-30. I maintain 15-20 psi at a hot idle and I regulate pressure to 75psi above 4000 RPM and I measure oil pressure at the back of the engine.

Let me know if you need help with the instruction from the BMS book.

Dave
Click to expand...

Thanks for the input. I was trying to get away from pulling the cover untill i was ready to go through the motor.Wich will probly be late summer or fall


I will see if i cant tighten up the pump clearances some and add the thrust plate to see what happens.
 
What kind of rod and main bearing clearances are you running..? IF clearances are loose you do have options... Calicoat bearings if the crank is cut or run, .001" over if its standard. It sounds like you have already done your homework with the timing cover..

FWIW I run similiar bearing clearances (.002-.0025) to turbodave231 and see anywhere between 17-19psi. Drop the pan and pull a cap and measure. HTH

Mike Banas
87GN
 
NC87GN said:
What kind of rod and main bearing clearances are you running..? IF clearances are loose you do have options... Calicoat bearings if the crank is cut or run, .001" over if its standard. It sounds like you have already done your homework with the timing cover..

FWIW I run similiar bearing clearances (.002-.0025) to turbodave231 and see anywhere between 17-19psi. Drop the pan and pull a cap and measure. HTH

Mike Banas
87GN
Click to expand...


Im not sure on the clearances the motor was already in the car when i got it unknown miles looks to have been gone through at one point.Id say they are a little loose for sure.


Can the pan be dropped with the motor in the car? i havent really looked at it id assume it can be.
 
You can drop the pan in the car as long as it is a stock pan and oil pump pickup. (Those fancy Lee Thompson oil pans are a PITA to do in the car!!)You can then plastigage the bearings. I hate using plastigage, but without removing the crank, this is your best alternative.

You can replace all the rods and mains without removing the crank. That may be the fix, but don't rule out the cam bearings as the source of the excessive clearance.
 
turbodave231 said:
You can drop the pan in the car as long as it is a stock pan and oil pump pickup. (Those fancy Lee Thompson oil pans are a PITA to do in the car!!)You can then plastigage the bearings. I hate using plastigage, but without removing the crank, this is your best alternative.

You can replace all the rods and mains without removing the crank. That may be the fix, but don't rule out the cam bearings as the source of the excessive clearance.
Click to expand...



yeah stock pan, I may end up pulling the pan for a look.
looked all day for a wear plate and differant thickness gaskets with no luck.

But on a side note after it sat overnight

85psi (fast idle) water temp less then 110*
60psi in gear


65psi@5,000
45psi 2,000 @165* water temp
30psi at idle


45-46@5,000
35psi@2,000 @185*water temp
12psi idle

dunno why the pressure is higher today :confused:
 
Pull the pan and look for crap or gunk in the p/u
My buddies car had oil pressure issues and when he pulled the pan there was a section of permitex in the pick up. (Still dont know how it got down there)
When we cleaned the pick up and put the pan back on oil pressuer went to 18lbs at hot idel and was 60 cold idel! all with mobil 1 5-W30 :eek:
 
thunderace31 said:
Pull the pan and look for crap or gunk in the p/u
My buddies car had oil pressure issues and when he pulled the pan there was a section of permitex in the pick up. (Still dont know how it got down there)
When we cleaned the pick up and put the pan back on oil pressuer went to 18lbs at hot idel and was 60 cold idel! all with mobil 1 5-W30 :eek:
Click to expand...
That is a definate possibility the previous owner use permatex blue on the oil pump gasket :confused: so no telling what else is in there
 
Bet ya 100$ thats your problem!

Blue is crap I wouldnt use it for anything on my car. Plus you should always use the right gasket there is a reason they make them :)
I use a little 3M Weather strip adhesive to hold them in place (not much just a dab and only on things like valve covers or oil pans never a oil pump! thats just dumb! but then thats just my .02 lol

good luck ;)
 
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