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During the past year or so, my oil pressure gage reading has been rising from the middle 50's to over 70. Since the gage stops at 70 this is worrisome.

I checked the pressure with a new gage screwed directly into the fitting at the rear of the motor, same place the sending unit screws into, and get a reading of about 65.   I don't see any signs of new oil leaks, so what might be happening here, and should I worry?  The cars runs super and I don't hear noises that shouldn't be there. Of course, the Hall off road exhaust system drowns out almost every noise other than my wife yelling at me to shut the damn thing off.

I would think that more miles on the motor or pump would eventually lower oil pressure, or is this like the human body that gets clogged arteries from too much good care?



Thank you,

Tom

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I have not changed oil type or viscosity, and change the oil at least once a year. The motor uses almost no oil, except for a very annoying minor leak near the front seal that I aim to fix this winter. The motor was rebuilt about 20 years ago and has about 15000 miles les on it since then.  The puzzling thing is that the pressure creeped up about 15 pounds over the last three years.

has anybody changed the oil pump without pulling the motor? Possibly  the pressure relief valve is sticking.

@tomkuester posted:

I have not changed oil type or viscosity, and change the oil at least once a year. The motor uses almost no oil, except for a very annoying minor leak near the front seal that I aim to fix this winter. The motor was rebuilt about 20 years ago and has about 15000 miles les on it since then.  The puzzling thing is that the pressure creeped up about 15 pounds over the last three years.

has anybody changed the oil pump without pulling the motor? Possibly  the pressure relief valve is sticking.

You can change the oil pump without pulling the motor.  The oil pan will have to be dropped.  If your car has the removable crossmember then it is less of an effort.  If the original crossmember is still there then it is a project to convert it to a removal unit.  Chopping out the crossmember is easier if your oil pan is stock.  It was somewhat of a challenge with my 10 quart aluminum oil pan.  I also had to remove the parking brake mount to get my oil pan out.  Once the oil pan is out the oil pump is readily accessible.

Take note that the shaft should have a friction-fit washer attached to it. Take note of its position and make sure to retain it. It is what keeps the shaft from pulling out of the oil pump should it stick to the distributor hex drive shaft when removing the distributor.

if that happens with a distributor removal, it will necessitate removal of the oil pan to retrieve and reinstall  the shaft 😕

Larry

@tomkuester posted:

I have not changed oil type or viscosity, and change the oil at least once a year. The motor uses almost no oil, except for a very annoying minor leak near the front seal that I aim to fix this winter. The motor was rebuilt about 20 years ago and has about 15000 miles les on it since then.  The puzzling thing is that the pressure creeped up about 15 pounds over the last three years.

has anybody changed the oil pump without pulling the motor? Possibly  the pressure relief valve is sticking.

I have changed an oil pump with the engine in the car. You just have to be able to take the oil pan off. Your high oil pressure issue sounds like an oil pump with a stuck relief spring.

I would imagine you would need to have the oil pan removed to get to that valve. At that that point it is only two more bolts to remove the pump and you can examine it in the luxury of your workbench.  It might be more practical to replace the entire pump since the outcome of cleaning or the replacing the valve will not be known until the car is back together.  And, oil pumps are reasonably priced.

This distributor will not move if all you do is remove the pan and oil pump.

The fit of the driveshaft into the pump and the bottom of the distributor shaft is not a difficult NASA precision fit and will pose no difficulty during reassembly.

if you decide to replace the oil pump, the generally agreed pump to purchase is a Mellings, standard pressure, standard volume.

Larry

If only DeTomaso had gone with a Chevy motor, the distributor/oil pump alignment would have been so easy, but no he had to go for looks and hid the distributor. Most likely I’ll replace the entire pump once I get started in earnest. I’m just trying to work myself up to the task since I’m 78 years old and don’t have a lift. But I love this stuff.

It may very well be a be a correct reading, and within proper tolerances, but I'm concerned because the pressure has climbed after about 20 years since the motor was rebuilt. Does that not make you wonder. No, I really don't want to go through the trouble of putting in a new pump. I'd rather leave that to the next caretaker.

Ford''s unhappy combination of an Italian Veglia oil gauge and the US pressure sender has always resulted in an inaccurate gauge reading. Gauges & pumps do not increase their reading due to age or wear. The reverse is what normally happens.

Likely the pump is just fine and the connecting wire has loosened a connection, changing the reading. Believe the mechanical gauge- the Veglia is only to tell you if the engine is running.

Tom, a few decades ago I colluded with a friend who worked for Ford and borrowed eight (8) brand new 351-C oil pressure sending units.  I tried them one after another in the garage on a thoroughly warmed up Pantera. I got six (6) different answers and none agreed very closely with the SW- mechanical, which is, like yours, on a Tee fitting back by the bell housing. Its still there after 30 years- bothering nothing & no one.

There's a second threaded oil pressure port above the OEM fuel pump that will give MUCH different results, so pay no attention to data from that spot. It is all but impossible to access on a Pantera, anyway

@bosswrench posted:

Tom, a few decades ago I colluded with a friend who worked for Ford and borrowed eight (8) brand new 351-C oil pressure sending units.  I tried them one after another in the garage on a thoroughly warmed up Pantera. I got six (6) different answers and none agreed very closely with the SW- mechanical, which is, like yours, on a Tee fitting back by the bell housing. Its still there after 30 years- bothering nothing & no one.

There's a second threaded oil pressure port above the OEM fuel pump that will give MUCH different results, so pay no attention to data from that spot. It is all but impossible to access on a Pantera, anyway

Useful for installing a safety pressure switch on the control of the electric fuel pump

The plate on the fuel pump opening is temporary, the final one will be "cleaner".

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