I have a 91 TBI engine that has 28psi @75mph and about 20 @ idle. It also only has about 80k miles but has been sitting alot. Any thoughts on what might cause this? If it is the pump how much room do you need under the pan to be able to sneak it out from the cross member. I only have about 2.5 to 3" of room. Any quick good fixes or ways to check what it may be.
Low oil psi!!!
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TRY SOME 20/50
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my bros 350 is the same, also a budies 400 is like that too
both have over a milion miels on them and have mechanicl gadges
both have over a milion miels on them and have mechanicl gadges
20# low???? bahhh I ran a 302 for over 2 years w/ 0 psi I ment zero psi @ idle and 5-10 tops on the road, my 400 runs 65-70 ish in the morning and will range from 15 @ idle to 40 cruzing @ 15oo rpm. I was always told 10 psi @ idle and 10 more per 1ooo rpm, yours sounds normal to me
~Nate~
~Nate~
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That's typical Chevy SB oil pressure. If you have "lifter noise" at 28 pounds of oil pressure, a new oil pump isn't going to fix it.
Thanks for the advise. I drained the oil and the sh!t was so thin!!
I put in 20/50 and a new filter and my psi is [email protected] idle and [email protected] cruse rpm. The lifter noise is gone and all seem well. I think it only had 10/30 or something close to it and it sat for a long time so who knows!
I put in 20/50 and a new filter and my psi is [email protected] idle and [email protected] cruse rpm. The lifter noise is gone and all seem well. I think it only had 10/30 or something close to it and it sat for a long time so who knows!
Going to a thicker oil is not gonna fix your oil pressure problem. Typical oil pressure on a V6,8 is 40 idle 60 run. If your reading lower on an ACCURATE guage then it means that your motor is wearing out.
If your pressure is uniformly lower throughout the rpm range then it's wear on anything but the rods and mains. If it's low and doesn't change through the rpm range then is the rods and main bearings.
When a motor is new the clearances are tight and resistance to flow is good (pressure). As the lifter bores and bearings wear resistance drops and flow increases. This is your first sign that something is up...soon you'll get to a point where oil pump flow is at a max and you have very low pressure.
Thicker oil will get the pressure up so you think everything is fine, but in reality your not flowing enough oil because the fluid is too thick. You'll hear much more start-up noise and you'll end up spinning bearings if you take the motor to high rev's.
Now, don't go thinking that your motor is gonna shit the bed soon it's prolly got a couple of years in it, but don't be surprised if the bearings spin or it starts sounding like you have rocks under the valve cover.
Correct fix: Rebuild the motor.
Cheap fix: Get a high volume oil pump.
If your pressure is uniformly lower throughout the rpm range then it's wear on anything but the rods and mains. If it's low and doesn't change through the rpm range then is the rods and main bearings.
When a motor is new the clearances are tight and resistance to flow is good (pressure). As the lifter bores and bearings wear resistance drops and flow increases. This is your first sign that something is up...soon you'll get to a point where oil pump flow is at a max and you have very low pressure.
Thicker oil will get the pressure up so you think everything is fine, but in reality your not flowing enough oil because the fluid is too thick. You'll hear much more start-up noise and you'll end up spinning bearings if you take the motor to high rev's.
Now, don't go thinking that your motor is gonna shit the bed soon it's prolly got a couple of years in it, but don't be surprised if the bearings spin or it starts sounding like you have rocks under the valve cover.
Correct fix: Rebuild the motor.
Cheap fix: Get a high volume oil pump.
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