Oil pressure at WOT

[Dieselboy.]

Having an odd issue.

Just installed a mech oil pressure gauge in the reservoir. Cold idle is 30ish psi. Warm idle is 11psi, cruising is 20 and it wont go any higher.

I can mash it from 2000 RPM and go all the way to 3400 and my Oil pressure gauge wont go over 21ish psi.

Anyone have any ideas on this ? I know its a pressurized system all together so really tapping in at the reservoir or off the filter housing shouldnt matter. It should see the same pressure, no ? What would cause my low RPM oil pressure to be fine but not move past 20 ?

 

[2000wa250]

I'm not sure, but am curious as well. My best guess would be a pump that is wearing out? Not exactly sure how it works but maybe something to do with the gears in it wearing down leading to good pressure when it has time to move volume, but when it has less time to move the same volume it is struggling?

Regardless, I will be following this intently.

 

[Dieselboy.]

New motor... 8k on it, I was doing some reading about the 3 pressure relief valves and Im wondering about them. Or possibly a weak LPOP

 

[KBMKVIII]

How many miles on lpop?
Did you inspect the front cover for wear marks when it was apart?

 

[907DAVE]

Gen 3.

 

[Dieselboy.]

The LPOP was just one I had from my old engine, bout 100k miles on it. So even a Melling would be a good upgrade. No the front cover was in great shape.

Gen 3.

Really ? Well thats not good. First Im gonna verify the gauge. But how would the Gen3 cause that bad of a drop ?

 

[907DAVE]

Remember this one:

http://powerstrokearmy.com/forums/showthread.php?t=11251

 

[Dieselboy.]

I do. Thats the thread I was looking for. Problem is at 3000rpm its still on 24 psi of oil pressure.

I dont feel as bad. Looking on the bright side hopefully (knocks on wood) I dont have to pull the oil cooler to check the valve.

The Melling pump, is it any better or should I bend over without lube and get Bobs HV LPOP ? I dont like low oil pressure.
Charles is very knowledgable but I still would like more the 20-25psi

 

[TARM]

I think adding the Melling is a good upgrade in general.

What about a weak spring is the PRV at the filter head? If that is weak or broken in someway it could explain why oil pressure stays consistently low no matter what the rpm. The other ball check valve upfront should only effect pressure unit pressure is equalized thru the system, sort of a quick fill bypass, so I doubt its the issue.

But if that Gen3 is sucking the res it could the cause. I would expect pressures to vary if that was the case though.

 

[Dieselboy.]

The main PRV that would be the problem is in the oil cooler. You have to remove it as its in the filter end of the housing. There is one that only is in place to bypass the oil filter if it clogs, which I can check on the next oil change.

And like you said the one up top I believe is only there in case of too much pressure.

Im curious to see what other gen3 users see at WOT.

 

[TARM]

I was speaking of the one you have to pull the cooler to access but yes I agree with the path you are taking.

I am getting ready to install a Melling M208 this week. I was able to pick one up from ADvance Auto of all places for $49. Its 70 then you use one of the on line coupons and check off pick up in store. I was lucky and one of the two local ones ( within 50miles is local out here for me) actually had one instock. I think that is likley the best deal you can get on one.

An ATI dampener is going on so I saw no reason not to include the LPOP.

 

[Dieselboy.]

Im almost contemplating throwing the old res back on to verify or eliminate the Gen3.

Melling is ordered. See if it helps. I through my fuel pressure gauge on it so electric vs mech and it seemed to read 5 psi higher at throttle. I found a few posts back and Dave said for ever 1000rpm 10 psi.
10 psi at idle
20 psi at 2000rpm
24ish psi at 2500 rpm. So its not terrible. I may also move the line down to the mains vs the res.