Sudden Engine Noise

I was cruising down the freeway at about 65 (no O.D.) when the engine sounded like it had run out of oil suddenly. Immediately put in the clutch and started to pull off when the engine started sounding fine again and the oil pressure looked o.k. Got home with no further problems. I suspect a sticky oil pressure relief valve. Anyone have other thoughts?

Dave, this sounds like the tappets ran low on oil supply. The main oil supply for the hydraulic tappets is from the oil filter and I would look for a restriction in the small orifice near the top of the center tube in the filter cannister. This could very well been over looked during a rebuild as could the small bypass valve. The bypass valve was intended to allow oil flow to the lifters when flow thru the filter was clogged so that too may need to be checked? The high RPM's during the highway speeds may have been what triggered the tappet noise. Rather doubt the relief valve in the oil pump stuck. By the way what is the running oil pressure?

Thanks for the tips, Dee. That's what it sounded like to me too. I was pretty thorough about cleaning out the lines to the filter canister and the canister connections, but I'll look again. Where is the bypass valve located? Is that the valve attached to the side of the oil pump or another one? My oil pressure gauge wasn't reading anything when I first fired up the engine. I had a shop check it with their gauge and they said it was within spec. Now when the engine is warm it's about 0 at idle and up to about 20 psi at high RPM. It I'll be ordering a new sender soon.

I mentioned the small orifice first as it's pretty easy to check....it's about a couple of inches down from the top of the center tube, about .040 -.060" diameter. The by pass valve is located under the large (15/16") hex cap next to the fuel pump bushing and will require the removal of the intake manifold in order to get at it. This brass valve ( 7/16" hex) is normally closed unless there is a pressure differential of around 4 psi between the oil filter exit line and the main oil line from the pump. They can malfunction/stop-up. The pump has it's own relief valve (on the side) and is set a fairly high pressure depending on which pump the engine has. The relief valve for the hydraulic tappets is located at the front of the valve chamber under a similar 15/16" hex cap. It's set at 20 psi so the tappets don't see too much pressure. If this ball and spring was missing it too would cause the tappets to run low on supply allowing the feed lines for the tappets too lose pressure.

I suspect the "real" oil pressure is higher than the 0-20 psi you mentioned?

Good luck ordering a new sender. I've tried to get several and they were junk or didn't work at all. The King-Seeley sender is a thing of the pass and are not available that I know of. I tried Ford units but they were made in China and aforementioned junk. I took my old one apart and fixed it (see posts in the forum section). If you do have success please let us know the part numbers and such. Instrumentation is my thing, I have a non repairable water temperature sender and I have been searching for a replacement for some time. It is also a King-Seeley type. Data on senders has disappeared since your FAPS went to computers. Anyone who has solves this mystery please jump in. Sorry to hi-jack your thread.

I found the previous posts. So the first thing I'll do is replace the pressure sender with a 48-9278 from Joe's Antique Auto so I can get a reliable pressure reading. I'll also test the new sender for accuracy and will try opening and cleaning the old sender. Next I'll check the filter center tube orifice. Then pull the intake manifold and check the bypass and relief valves and the fuel pump pushrod bushing. Failing all those things, I'll order a high capacity fuel pump from Alan Whelihan. Will let you know how it goes.

I had a similar oil pressure problem that turned out to be a failed 0 ring gasket on the oil pump. During engine rebuild the oil pump was replaced by a rebuilt pump (I think) from EGGE. I replaced the pump with a Melling high output pump. The 0 ring gasket sitting on the shelf in the shop still on the pump actually broke up even more after a year. So you might have to check out the pump too. Oil pressure on a new pump should not be 0. It could be very hard on the valve lifters and cam shaft as it was on mine.

I would open up my old one before ordering a new one. The one from Joe's is going back. It came from Dennis Carpenter by way of Joe's. It has made in China printed on the box. I don't know for sure but the data in the Ford Service Bulletins does not look correct for the cycle rate on the points. Again, not for sure but my sender/gauge work great now and no way the points are cycling at 125 time a minute at 25 psi.

I installed a mechanical pressure gauge in parallel with the pressure sender and the readings of the two gauges match. When the engine is moderately warm (I don't have thermostats) the oil pressure is just under 25 psi at about 3000 RPM and falls to less than 5 at idle. This is with 10-40 Valvoline racing oil. The center tube of the oil filter has no orifice - appears to be the same diameter all the way to the bottom. How critical is the orifice? Next step is pulling the intake manifold I guess.

As far as I know from my 47, the orifice part way down the center tube is the only exit for oil to leave the filter, so it is critical. But I don't see how it would cause low oil pressure reading unless the filter canister is full of air instead of oil, as the sensor is before the filter. I suspect the pump is the problem.

The orifice is critcal as far as oil flow thru the filter. You may have to remove the filter from the engine in order to get a good look at the inside of that center tube. A dental pick might be handy when "scratching" the inside of the tube in your search. The orifice should be located near the top just below the top of the cartridge (when installed) and I suspect it's cruded over so it's not real easy to find. I would do this first before going after the by-pass valve under the manifold. Your oil pressure is typical of an engine with a few miles on it. You might want to use 20-50 the next time you change.

Thanks! I'll look again. Oh, and Merry Christmas!

Since my filter canister is on the bench I thought I would measure the location of the hole in the center tube. It is 5 inches down from the top and about one half inch up from the umbrella rest that stops the filter from going lower. I don't know if they are all the same but that is where the hole is on mine. Hope that helps.

After I sent the last reply I wondered if the tube can be installed upside down?

Thanks Ralph & Dee. Pulled the filter canister and found the orifice on the side of the center tube. It looks clear and I could run a wire through it. I had been thinking the orifice was in the center of the tube and that there were large oil passages at the base of the tube.

If the entrance fitting on the side and the exit elbow on the bottom of the cannister are clear then it seems there should be flow thru the filter. What type of filter cartridge are you using? Perhaps something super-fine might hinder flow? Before digging into the by-pass valve and/or relief valve why don't you try running the car with out a filter cartridge now that you know there's no blockage in that system.