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Purchased a Packard with a "rebuilt" 288 engine Oil pressure at engine is 10 psi
any ideas what they did not do or left out? Thanks

It would be helpful if you'd tell us the conditions under which you have 10 psi? Hot idle? Road speed? Cold or warm? Oil viscosity?

First thing I'd check would be the oil pressure relief valve. If the piston moves freely and you're in doubt about the spring, add a washer to shim the spring and check the resultant pressure for a change, if any.

If the problem is happening at driving speed and the spring and pressure relief valve is OK another question is did someone "rebuild" the oil pump when doing the other work. Several have had issues with oil pressure after the pump has been worked on because too thick a gasket was used on the end plate when putting it back together.

As to things that might have been left off, there is a plug with an orifice at the front of the lifter gallery that if it was missing would let oil drain into the timing chain area. The lifter gallery pressure would surely be affected but not sure whether the overall pressure would be lowered to the extent you are seeing.

Oil is 15-40
New rebuilt oil pump was installed
Can has not been driven due to low Oil pressure and no change in pressure on fast idle
No bottom end noise yet, some top end noise

Connect a manual pressure gauge and see what reading you get.

Good Day...Have you considered speaking with the folks who rebuilt the engine? Does the engine have a warranty? Ernie in Arizona

10 psi IS FROM A MANUAL GAGE AT THE BLOCK
owner IS DECEASED
REBUILD WAS 15 YEARS AGO

If that's your cold pressure then I would check to see if the oil pump relief spring is weak. Some have had to shim their spring to compensate for a weak spring. A shim could be a quick test to see if the pressure increases. Other than a worn pump, or too thick of a gasket, the only other thing would be loose main bearings. Your sure your gauge is accurate? and you tested it off the block without the oil filter T in place?

You said it is a 288 block so engine would have to be 1948 or later. A couple of things to check. The bottom port on the drivers side is direct from the oil pump and should be at approx 40-50 lbs at driving speed. At idle speed it can get down to approx 10 lbs but much lower than that and the idiot light would go on in the 51 and later models that had that indicator light. The upper port on the drivers side is the inlet to the oil lifter gallery and is fed via a pigtail from the bottom port. Depending on which port the gauge is testing there could be a difference if a couple of conditions are present.

If the replaced oil pump was NOS then probably not the issue but if it was rebuilt and a wrong gasket was used, clearance between rotors and end plate will be too high and the pump cannot develop the proper pressure. Several have reported finding ordinary gasket paper used but the original was almost like tissue paper. I believe it was Ross who said he makes his gasket out of "onion skin" typing paper.

There are plugs at each end of the lifter gallery. According to some service articles, if the back one is missing the oil cannot escape but if the front one is missing oil could be freely flowing into the timing chain area which could lower pressure.

On some blocks with the early versions of the filter the supply coming from the bottom port had an orifice in the brass block to restrict flow to the filter. If the block is reversed and the orifice is on the lifter gallery side and the gauge is plumbed to the upper port it could read low. The same low reading could be present if there is no restriction in the brass block (or in the oil filter assy itself with later filters) and oil is just freely being dumped into the pan. That would also have a low reading if the gauge is in the upper port and possibly also at the lower port.

One other thing being assumed is with the rebuilt engine the oil pan was cleaned out so no sludge is present and also it had oil in it or if not, was stored in such a way that no furry critters could have built a nest in the pan and obstructed the oil pickup screen.

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Thank You All I will take it from there Bob