Virgin 47 engine low oil pressure

[Bubsyouruncle]

I bought the business coupe, with the engine, in 1963 from the original owner who, no kidding, was a little old lady who didn't drive it much. She was a neighbor that we had known for years and years. Can't tell you the miles on the car when I bought it because, at the time, I didn't care.

But to the best of my knowledge, and I am 100 percent from '63 on, the heads have never been off, the pan down, or the intake removed. They don't get much cleaner than that.

I used it, and abused it, from September of '63 through August of '64, while I was a senior in college in Milwaukee. Reliable as all get-out. Even at below zero temperatures. From then on it has been pretty dormant. I have started it up every decade or so, and it has always responded appropriately.

But now, in the twilight of my years (cue Frank S), I want to drive it some more. But I think (know) I have a problem.

Using 50 weight oil, at start-up I get about 10 to 15 psi. Once it warms up it drops to near to nothing. Rev it up and it rises a little. Just a little. Tells me at least that the oil pump is functional.

Cranking compression pressure is 75 psi all around. Plugs are carbon-coated, but they are "new" and haven't seen more than 15 minutes of use at idle at one time in the last 20 years.

The water pumps leak - no kidding!- and will get worked on this winter.

The only replacements on the engine since 1963 have been distributor, carburetor, fuel pump, and spark plugs and spark plug wires.

Comments, suggestions, directions, offers of assistance, etc., are welcome.

[Merc Cruzer]

Test with a mechanical gauge to see if you get the same readings.

[Old Henry]

I don't see any cause for concern other than maybe the low oil pressure but that could be the sender. It was for me. Here's a cheap simple setup to test the oil pressure: https://www.fordbarn.com/forum/showthread.php?t=68156

[Bubsyouruncle]

I am using a mechanical gauge.

[Bubsyouruncle]

Nice wheels. Looks like the car I took the engine out of. Except it was grey, not black.

[Bubsyouruncle]

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After my quick reply I went to the site you suggested. It is scary to see exactly what I am seeing. Oil and air in the nylon tube.

Gotta say I got low oil pressure. Big time.

[Old Henry]

Doesn't matter what's in the nylon tube whether it's oil or air or water or beer. It's just transferring the pressure from the circulating oil system to the gauge. Any gas or liquid will work. The tube comes empty (air only) and gets a little oil pushed up in it when the lubrication system is first pressured up. If you're using a mechanical gauge it does look like your pressure is low. BUT, pressure is not as important as flow. You've probably got plenty of flow even at very low pressure (above 0) and don't need to worry too much about it.

[G.M.]

There is a bypass valve on the pump which is most likely the problem. The springs on some get weak and they usually show oil pressure cold or every time you start the engine and when the valve starts leaking the pressure slowly drops. When the bypass valve leaks bad engine parts a not getting oiled good. Depending on how weak the spring is determines how low the pressure drops. On a Lincoln V/12 with oil operated lifters when the pressure gets down to about 10 or 12 pounds the lifters start making noise and the lower the pressure gets the louder the noise. When the pressure gets real low the oil is being dumped by the bypass it comes out of the pump before ever getting into the engine. We made a set up to test the pump and made a spacer on the spring to get 55 pounds pressure and when installed that's the pressure the engine had. G.M.

[Kurt in NJ]

An original car could have a sludged up pickup screen
the 46 I had only showed pressure at idle when it was cold, not much hot off idle ---it got flogged a lot, never killed it

[bobH]

Kurt... X 2. If it has no maintenance, and non-detergent back in the day, I'd certainly want to check that screen. Hopefully with a light through the drain hole.
Back in the day, the 'used-car-lot-special' on this was to simply take a screwdriver and poke a hole in the screen (through the drain hole). (I wouldn't suggest that 'fix', today.) Just an opinion.

[Bubsyouruncle]

Thanks for the feedback. I will check the screen through the drain. Then, I suppose, I will have to drop the pan. Ugh. That may have to wait a little while.

[keith oh]

Years ago, in the no detergent oil days, another "Used car lot procedure" for sludged up engines was to drain all the oil and replace with Kerosene, start it up and idle for a min or so then drain out the crud. and fill with regular oil. It usually did the job and I don't ever remember harming an engine, after all Kerosene is a very thin lubricant.

[Old Henry]

Originally Posted by keith oh

Years ago, in the no detergent oil days, another "Used car lot procedure" for sludged up engines was to drain all the oil and replace with Kerosene, start it up and idle for a min or so then drain out the crud. and fill with regular oil. It usually did the job and I don't ever remember harming an engine, after all Kerosene is a very thin lubricant.

That's one of the things I did to clean out my engine that had sat for 31 years before I started it up. Plus, I wrapped a popsicle stick with paper towel and scraped as much of the sludge as I could out of the bottom of the oil pan through the drain hole. Drove it 10,000 miles after that before having it rebuilt. Ran fine.

P.S. You might want to have a look at my video on YouTube of starting that engine after 31 years. Over 700,000 have thought it entertaining so far. https://www.youtube.com/watch?v=wY389S_KUjs

[Kurt in NJ]

I have some modern Mercedes that have the extended oil change and built up some sludge, they would have a stroke(suck up clumps of sludge)---a treatment of 'blood thinner" (lifter cleaner detergent) was enough to clear the screen without dropping the pan(engine removal) 2- 500 mile oil changes with a double dose of cleaner -- only as a last resort for people too cheap to fix it properly, but it did work, the problem had not reoccured 3-4 years later(one car died in a flood, other tried to move tree)

[Robert Dip]

Old Henry....watching the video, and I had my fingers crossed.....one backfire and your eyebrows would be no more. OK...it brings back memories from the early 60's, in starting up a '48 Coupe with a rebuilt flathead. I used a glass, and I slowly poured in the gas, mush like you did, when the engine started, it also sucked in the glass over the carb and shattered to pieces. Had to take off the carb and manifold to get the bits of glass out....Ah, the good ole Days......and starting up an old car after so many years is something that stays embedded in our minds forever.....and you have it on video. Fun.....Robert

[Bubsyouruncle]

Great movie! Engine even sounds pretty good. How was the oil pressure, btw?