celeryman22

Guys, I have low oil pressure at idle on my freshly rebuilt motor. The motor has a new oil pump (sealed power) new bearings etc. I plastigage the bearing when I put them in to make sure everything was ok and it was. The crank was reused but was in excellent condition. Im using 10W30 oil. The oil pressure reads below 5psi at idle.

What can cause this? Will a better oil pump help? I see the sealed power pumps are one of hte cheapest you can buy...

Any input will be helpful.

Thanks
Mike

Gordonm

What year is the car and does it have a mechanical gauge. I just replaced my gauge and found out my oil pressure was much higher than it had been reading. Toying with the old gauge showed me the gauge was sticking and not giving a correct reading. Even a bad sender on an electric gauge can give you this.

markdtn

Possibly the bypass on the pump is stuck open or a plug was left out. I would check it with another gauge, if it's still low I'd change the oil pump. If it's still low it might be missing one of the plugs behind the timimng chain. Lets see what others say.

celeryman22

It is a 1980. I have tried a different gauge and both read the same. The oil pressure does increase as I rev the engine but not to where I'm happy with it.

Mike

MILO

Chek your pressure with another guage. If it were that low at idle I would suspect the engine would be knocking. When you plasti-guaged the bearings, did you do all the mains and rods? If you were toward the upper limit of the recommended limits, there may be some slop in the bearings. How the pressure at cruise RPMs?

MILO

One last question did you put in new cam bearings? A higher volume/pressure might work out for you, if you didn't want to tear the engine apart again. I did read somewhere that plasti-guage isn't that reliable. It's OK if your not going to push the engine or doing a quick rebuild. A micrometer works really well for this because you can see if the crank journals are out of round.

pauvil

You can also look at the rockers when it's running at idle, if they are oiling your pressure is good. What was your bearing clearance on your crank?? If a plug was left out usually you would have no pressure, a lot of bearing clearance will cause this.

celeryman22

I did the rebuild of the motor last year, so I can't remember the bearing clearances. I do know that they would have been good or I would have stopped rebuilding the motor. I did measure all of them. I did change the cam bearings also.

At idle the rocker have no oil coming out of the pushrods. At increased idle they start to come out.

If a plug was let out would it be 0 pressure all the time? I do get some pressue when I rev the engine.

Mike

pauvil

Did you use platigauge on the crank or just mic the journals?? Also, at idle the oil won't be squirting like crazy out of the rockers but more like falling out, sometimes hard to see, are they wet??? Also look for the oil building up to drain back down, do you see any at all?? If your not oiling to the top then don't run the motor. Is it possible that your gauge line is leaking?? check it. Your getting pressure so I don't think you have a plug in the motor out, also like mentioned before the check valve in the pump could be stuck, something to think about before you tear the whole thing down. When bearing clearances are loose, like in an older motor, you get symptoms like this, Good Luck, hopefully it's the pump or a leak in the gauge line or something like that.

SanDiegoPaul

The reason for the no oil on the upper end at idle, is that lack of pressure. You built the motor last year? How many miles on it with low oil pressure? What kind of pump did you use and what kind of pickup screen? Did you check clearance between pickup and the bottom of the oil pan?

celeryman22

Yes, I rebuilt it last year. 0 miles on the car since the rebuild. Car is still undergoing restoration. Almost done now. Its a sealed power high volume oil pump 26.99 at summit racing. I see others that are near 50.00 so I'm wondering about how well it actually is. The pickup screen is from the original oil pump. As far as how far it is from the bottom of the oil pan I can't really remember.

I have also read that there is a high pressure release valve about the oil filter, I'm thinking this may be the problem. I am going to go home and check to see if it is in place or if the oil is bypassing through the hole. If I cannot see anything there I am going to pull the oil pan and check the pump next.

Update:
Check the bypass at the oil filter and it is clean and not stuck open. At 1000 rpm im under 10 psi and at idle I would say near 5psi.

Mike

blue427

your pickup may be sucking air if it's not a good fit.you put on a used pickup which can vibrate loose very easily

celeryman22

I am going to pull the oil pan tonight and check the pump, the depth, etc. What are your guys thoughts on the sealed power pump? Are they all made the same? Would on of these better more expensive pumps work better?


Update:
Pulled the pump and its a melling 55HV not a sealed power. The depth of the pickup looked ok, but I will readjust and tack it on.

I am going to look at pulling the timing chain cover and check out the plugs.

Thanks
Mike

hawgn68

Celeryman,
I'll bet you a buck you left one or more plugs out of the lifter galley, right behind the cam gear. Don't ask me how I know, but your symptoms are very familiar... Take the timing cover off, and then the cam gear. Good luck, it's not your pump.

Jim

wills670

Might be a loose oil pump to the main bearing or loose lower body bolts.
If it is sucking air thru to pickup tube ther will be tiny air bubbles showing up at the push rods. Take the oil pan off and check before you spin a bearing.

markdtn

I doubt it is the bypass valve at the filter, that just protects the filter from overpressure. More likely the release valve on the pump is stuck open. Nothing wrong with Sealed Power IHMO. It could be that your pickup screen is dirty. Not sure why anyone would spend big bucks rebuilding an engine and not get a new pickup screen for $5 or so. It could also be that trash from the rebuild is now blocking the pickup screen (had that happen on a 318 I built once) or it's slammed against the pan and can't get enough flow (had a friend ruin a 400sb this way). If it was me, I would pull the pan, change the pump and use a new screen with verified clearance. You can get a screen and a Melling pump at any Autozone. Probably less than $40 with a new gasket. If that doesn't fix it, you probably got too much clearance somewhere or a galley plug out.

MotorHead

Verify the clearance of the pump pickup to the bottom of the oil pan, use some plumbers putty

big_G

And while you have the rear main bearing out, under the cap I think there is a oil passage plug in the block. Make sure it's there.

Mr.L

I had a problem like yours(not as bad) on the 350 in my 69 camaro. I had 10lbs at 650 rpm, but it went to 80lb. after 1500 rpm. Check the oil galley plugs under the timing chain, mine were ok, but you never know. That was not my problem, it was the oil pump same type. I bought one of the reworked pumps from summit and it fixed the problem. I now have 40 at 650 and goes to 100 after 1500. I usually check mine using a high speed drill with the pump shaft drive rod (tool) attached. With this motor I skipped this and paid the price. Good luck

howler

This is what I wanted to say also. I just read about this somewhere the other day but I can't recall right now where. But this could be a serious problem.