Low oil pressure question

StuckinCincy

StuckinCincy

Member
My oil pressure drops to about 10psi when the truck is at idle and warmed up, the engine has recently been rebuilt and has less than 1000mi.

My question is about the oil filter boss on the block. Should there be a plug or second bypass valve in the inner hole? If that port should be closed which is the prefered method? I'm still using the factory remote filter mount with it's bypass valve. I have done a search and haven't come up with a definite answer.

Thanks in advance.
 
Neelsonwheels

Neelsonwheels

Donating Member
Re: Low oil pressure question

Factory gauge?
I had a similar issue with a new build. Mine was due to pick up tube seperating from the oil pump. I would drop the oil and probe up into the pan with a wire or similar item. My pick up was laying right on the bottom of the pan. I replaced my pump with the RPM high pressure pump while I was in there. I have good pressure now. I didn't trust the original pump even though it was fairley new. I felt it may have worn prematurely due to cavitation. It was also stock pressure and volume pump. The RPM unit comes with the pickup tube nicely welded to the pump. Good luck.
Also have you checked the oil filter for bearing material? Also what are the tolerances that the builder used for the mains. The tolerances in the bottom end have a big effect on the oil pressure.
 
wildphil

wildphil

I Love My Ty's
Re: Low oil pressure question

I hope it is not the same problem that I had. I had good oil pressure on my new engine for awhile. Then I noticed my oil pressure dropped to 10lbs. when warm. Ended up being my main bearings doing out.
 
atkonkler

atkonkler

Is this your bush?
Re: Low oil pressure question

Cut your oil filter open and look for metal! If metal is found time for a rebuild! :-( it sucks but better than letting it get really bad and make that spectacular noise! Yack yack yack =owie owie owie!

Good luck brodie!

Aaron
 
SyTyAddict

SyTyAddict

Member
Re: Low oil pressure question

I assume that you are talking about the off-center smaller hole on the block filter pad? I think all, or most of them, have a second bypass valve in the block, if it doesn't it should be blocked. If the bypass hole in the block is open, it shouldn't affect oil pressure that much, but you will be sending large quantities of unfiltered oil through the motor.

The stock oil pressure gauge tends to be rather inaccurate, I would put a mechanical gauge on it after you verify that the filter isn't full of metal.
 
The Devils Own Chariot

The Devils Own Chariot

Active member
Re: Low oil pressure question

DSCN0827.jpg

Cut your filter open and ook for copper flakes. My oil pressure was low to start and then turned into fluttering pressure and then pressure went to dropping when under acceleration. No noises and still ran good. Good Luck.
 
StuckinCincy

StuckinCincy

Member
Re: Low oil pressure question

Thanks for all the suggestions.
I'm using an autometer electric oil pressure along with the factory gauge an both showed low pressure. Mine was missing the bypass valve in the block. So it was sending unfiltered oil through the system. I don't know if that was why the pressure dropped at idle. I had pulled the pan planning to install a high volume pump. I pulled a couple of main caps and one of the rod caps to inspect the bearings. There is some damage, so it looks like I'm going to have to pull the engine again.

Craig
 
wildphil

wildphil

I Love My Ty's
Re: Low oil pressure question

That really sucks. I was hoping you would get lucky and have a easier to fix problem.
 
wildphil

wildphil

I Love My Ty's
Re: Low oil pressure question

There has been quite a few rebuilds that are loosing bearings. What brand of bearings did you use. Just wondering.
 
BoostedSUV

BoostedSUV

Active member
Re: Low oil pressure question

My fresh rebuild lost the bearings early on twice. I switched to Clevite bearings and have been good ever since. Luckily my machine tshop ook the hit and rebuild it for nothing.
 
wildphil

wildphil

I Love My Ty's
Re: Low oil pressure question

BoostedSUV said:
My fresh rebuild lost the bearings early on twice. I switched to Clevite bearings and have been good ever since. Luckily my machine tshop ook the hit and rebuild it for nothing.
Click to expand...

What bearings did you use in the other rebuilds? Clevite bearings were in my first rebuild.
 
wildphil

wildphil

I Love My Ty's
Re: Low oil pressure question

I don't have a stock tune. But after the rebuild I never drove my truck without monitoring the AFR. While driving as rich as I recall was at 10.9 AFR at WOT along with alky.

Now I did have a issue were at idle my AFR was in the 10's. For maybe 3 starts. Letting the engine run about 2 minutes each time. I changed my oil after correcting the tune and before driving. Would that dilute the oil enough to cause a issue with my bearings?
 
SyTyAddict

SyTyAddict

Member
Re: Low oil pressure question

wildphil said:
I don't have a stock tune. But after the rebuild I never drove my truck without monitoring the AFR. While driving as rich as I recall was at 10.9 AFR at WOT along with alky.

Now I did have a issue were at idle my AFR was in the 10's. For maybe 3 starts. Letting the engine run about 2 minutes each time. I changed my oil after correcting the tune and before driving. Would that dilute the oil enough to cause a issue with my bearings?
Click to expand...

I highly doubt that that would have caused a problem. It probably would have been ok if you didn't change the oil, but it's good to be safe.
 
D

Damian

Member
Re: Low oil pressure question

Dave, I still have the stock tune and my bearings went out. My builder said its very common for these V6s for the bearings to go out. He recommended aluminum bearings because they are stronger, and they happen to be a bit cheaper as well. So I plan on using them this time around, I hate pulling this motor, especially less than a 1k miles.

Also, if something is going to go wrong, it's going to be within 1k miles or so, not 20k down the road.
 
wildphil

wildphil

I Love My Ty's
Re: Low oil pressure question

Damian said:
Dave, I still have the stock tune and my bearings went out. My builder said its very common for these V6s for the bearings to go out. He recommended aluminum bearings because they are stronger, and they happen to be a bit cheaper as well. So I plan on using them this time around, I hate pulling this motor, especially less than a 1k miles.

Also, if something is going to go wrong, it's going to be within 1k miles or so, not 20k down the road.
Click to expand...

I will be trying aluminum bearings this time also. Dave suggested that I try them because of them being harder. I sure hope things work out this time. It is to costly to be rebuilding all the time.
 
D

Damian

Member
Re: Low oil pressure question

Tell me about it. I really don't mind working in this truck. It just seams like you take one step forward and two steps back with them.
 
Ty 1885

Ty 1885

Member
Re: Low oil pressure question

Hey guys aluminum bearings (KING BEARINGS) are actually softer than reg bearings, they can last longer because they absorb material better (dirt, and other crap).

After talking to KING BEARINGS, they said that aluminum bearing are better for cast cranks.
 
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