troubleshooting oil pressure

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67Dart273 said:
How about a cracked / broken oil pump? I myself have had trouble with pump / pan interference, and others have had troubles with ARP main cap bolts

I'm not referring, here, to pickup striking the pan, but rather the pump body hitting the rear of the pan
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I usually run a high volume oil pump and have to use my trusty ball peen hammer to hammer on the pan so it fits over the oil pump correctly. I like to make the oil pan where it sits flat on the block without the gasket, then it will be fine with it. If you bang on the oil pan in the right places long enough, you can get it to fit.
 
I had a low pressure problem on prelubing my 340. It was the brass ring(name escapes me) on the oil line to gauge. It collapsed wrong and pinched off the line. I could hear the drill pull down but had no pressure at mechanical gauge. Easy fix.
 
Lots of great suggestions in this thread. If all else fails you may want to consider lifter diameter if you changed them. Even .001" small and oil pressure is significantly reduced. J.Rob
 
Well the plugs are in place behind the thrust plate.

So I'm not sure what it should look like when running the pump while looking at the front main bearings because I have never done it before. But it does hemorrhage alot of oil and its cold oil at that. It is a pretty instant smooth run out of the bearing. Am I onto something?

I feel like I'm going to pull it and check bearings I suppose.
 
TomSchichtel said:
Well the plugs are in place behind the thrust plate.

So I'm not sure what it should look like when running the pump while looking at the front main bearings because I have never done it before. But it does hemorrhage alot of oil and its cold oil at that. It is a pretty instant smooth run out of the bearing. Am I onto something?

I feel like I'm going to pull it and check bearings I suppose.
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Yes, if you want to trace the oil pressure loss, take a priming tool and spin the oil pump and look for where the oil gushes out, There should be your problem. that's how I found my problem was the oil galley plugs behind the thrust plate.


If it is gushing out of your bearing, you may need to check the clearance of the bearing to crankshaft. If you use plastic gauge, you should remove the crank and wipe the oil off of the bearing and measure it dry. The oil can give you a false tighter reading.

Also if you take the bearing cap off, look on the back of the bearing shell. It should be marked on the back of the bearing shell if the bearings are oversize or standard ("STD" - and not a sexual disease...).
 
By the way is there ANY possibility that you have suffered fuel dilution? Are you sure about engine temp?
 
While you are in there, check the oil pump internal clearances even if it is brand new, unless you did it prior to assemly. If you do check, make sure you include the pump cover clearance.

BTW, I could not tell if the bearing is losing a lot of oil; I never had a low pressure issue nor any need to test. If you use the plastigage, you need to wipe the oil as noted above from all journals. Was the block line bored as part of this rebuild?
 
..............Many 74-76 360s had this problem right from the factory...50-60 cold, then only 10 or less psi warm.............kim........
 
How do you have the oil pump fastened down? If you are using an ARP or similar stud, these have been found to somehow not allow the oil pump to mount flush against the rear main and a pressure loss will result. Regardless of what you are using, that's a good place to check for trouble.
 
Sounds like with the stock pump it's fine. Replace the relief spring and it should go up to about 55-65 hot which I'd say is fine for the clearance (within stock specs). I'm not sure if there was a problem with the first pump but the result you got is typical for tight clearances and an HV pump... So stick the MP kit in and I think you're good.
 
The block was line honed before assembly. And I am using stock bolts to hold the oil pump on. The thing with the bolts is I had to call ARP and get two different main bolts to replace the ones sent in the kit as the bolts sent originally had a tall collar built in, because as you mention the pump wouldn't sit flush. So I believe that is what you are talking about rustyratrod, and that should be good to go.

Plan A: I feel that I am going to reassemble the timing cover and intake, as well as drop the pan and put the mopar high pressure kit in the pump and see what happens.

Plan B: If that doesn't work I'll check bearing clearances with dry journals as suggested.
 
ARP

Make DAMN sure you carefully inspect that the pump is not interfering with the cap bolts, and that the pump does not appear to be damaged/ cracked

INSPECT for damage between the pump and pan
 
well I ordered the high pressure spring kit. year one online notes says it ships withing 1-4 weeks... so I will keep you guys posted once I recieve/install the parts. Thank You for the advise and instructions!
 
I did make sure that the pump did seat flush with no interferance after getting the correct rear main bolts from ARP, this was a small hang up during my build. But ARP sent the bolts for free and quickly once I called them. It seems to be an issue they get calls about often. So they had the fix already figured out. Seems like they would change the two bolts out before shipping. But they were quick and professional.
 
what type of cam and lifters are you running in there ?
 
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