Topic: 0il pressure ??

nuffsaid    -- 01-30-2019 @ 6:25 PM
  I have low oil pressure in 50 f-1. no noise, or knocks. engine sounds good. been setting long time. Oil pump ? no sludge in engine.

alanwoodieman    -- 01-30-2019 @ 6:53 PM
  couple of questions, one- have you checked with a mechanical gauge? 2-do you have an oil filter?3-how long has the oil been in it and what viscosity are you using 4-low oil pressure cold or hot? or both?

carcrazy    -- 01-30-2019 @ 7:53 PM
  I would suspect the original electrical gauge. I have had this problem on a couple of 1953's and solved it by mounting a mechanical gauge either under the instrument panel or where the clock once resided. With my cars, when the in-dash electrical gauge showed about zero at idle the mechanical gauge showed about 20 PSI. I use an SAE 30 HD oil.

nuffsaid    -- 01-31-2019 @ 11:31 AM
  Getting ready to apply mechanical gauge and see what it reads. it has an oil filter w/new filter, 10-w-40 oil. Engine hadn't been run in 20 years. It runs great, just not very high oil pressure. Got side tracked in the restoration of it.

alanwoodieman    -- 02-01-2019 @ 6:34 PM
  post the results of the mechanical gauge test and we will go from there. oil filter canisters have a restrictor orifice on the inlet of the filter, if this is removed the oil pressure will be very low

51f1    -- 02-03-2019 @ 7:50 AM
  Are you sure you have low oil pressure? The first thing to do is hook up a mechanical oil pressure gauge where your sending unit is connected and verify your pressure is low. Inexpensive gauges are available at car parts stores.


nuffsaid    -- 02-03-2019 @ 12:38 PM
  hooked up manual gauge, oil pressure made it to 20. drove it for about 8 miles, then noticed the pressure dropping, and went to 0. never had that happen before. no knocking, nothing. checked oil, not low. noted fitting into filter had the restriction hole, cleaned it out before reinstalling it.

Fired truck up this morning, oil pressure went to 22, let truck warm up, at idle pressure went to about 12. only thing i can think of is something maybe to do with oil pump.

This message was edited by nuffsaid on 2-4-19 @ 7:01 AM

TomO    -- 02-04-2019 @ 8:34 AM
  The easiest thing to try is to remove the oil pan and check the oil pump screen. if it is clean, then I would replace the oil pump. Some trucks has a cleanout plate on the oil pan. You could remove the plate and clean the oil pump screen. I don't think that you could remove the oil pump through the opening.

If replacing the oil pump doesn't give you at least 40 lbs cold and 30lbs hot at 1,000 rpm, you are looking at an engine rebuild. Your engine should have the 80# oil pump and the pressure relief valve is on the pump. My car engine has 60# cold and 50# hot at speeds above 20 mph with 10w-30 oil.


nuffsaid    -- 02-04-2019 @ 11:13 AM
  Thanks Tom, Probably have it rebuilt. Then I won't worry so much about it.

TomO    -- 02-05-2019 @ 9:14 AM
  I would not rebuild a good running engine. You may be just throwing money away and you may introduce new problems. It is always bet to just fix the problem you have, rather than try to make the vehicle perfect. Very few shops do good work today and there are none that can make your engine perfect.

Have you checked the compression? Get the engine to normal operating temperature by driving the truck for about 30 minuted, remove all spark plugs, open the throttle all the way and with a fully charged battery check the compression on all cylinders. If any cylinders are more than 10 lbs less than the highest cylinder, add a small amount of oil to that cylinder to see if the reading changes, If it does you have worn rings, if it doesn't than you have a valve seating problem. Typical readings would be around 115 lbs.

If your compression is equal within +or - 5 lbs, your engine is probably not worn out and your oil pressure problem can most likely be repaired by cleaning the pump screen or replacing the pump. The restictor opening to the oil filter may also be enlarged, you can check to see if this is the problem by removing the line at the block fitting and plugging it. Then take a new reading of your oil pressure.


alanwoodieman    -- 02-07-2019 @ 4:13 PM
  sound like the oil pump screen is clogged or the relief valve on the side of the pump is stuck open. also did you change the fuel pump, maybe to electric? if the fuel pump push rod was removed that can cause low oil pressure. I have cleaned the screen by filling engine with kerosene and let it soak for overnight, have also used a blower heater to heat up the oil pan to loosen the sludge, any chance it has the truck clean out bottom plate? if so remove an clean sludge

danel321    -- 04-05-2019 @ 12:07 AM
  which oil filter do you use? and when do you change it means how long do you use one filter? I had faced this problem in a towing truck of 24 Hour Towing in New York, but after discussing with someone on a forum he suggested me to change the filter this is how I got the solution.

nuffsaid    -- 04-15-2019 @ 5:00 PM
  Well, Just a little up date here. After 2 months or more, Put my truck in the hospital for a heart transplant.
for a truck that ran almost like a new one it did have some issues.
like the block was cracked in several places. no leakage anywhere. it had 3 different kind of lifters in it, different kinds of valves, 1 cracked head, the reason for low oil pressure? Who knows. Everything was rebuilt back with all new parts. purrs like a kitten now, with 50 pounds oil pressure.
Thanks to all for your help and suggestions.

nuffsaid    -- 04-15-2019 @ 5:08 PM
  one more thing, my 1950 f-1 v-8 has a 4 speed transmission. would a 3-speed floor shift bolt up without any modifications ? Thanks in advance.

51f1    -- 04-30-2019 @ 6:11 PM
  This is a related oil pressure question.

I had a NOS oil pressure sending unit in my rebuilt '53 engine ('51 truck). My dash gauge always showed 50 psi after I rebuilt the engine. The NOS sending unit failed. I ordered a new sending unit from Carpenter. The dash gauge read 30 psi. Got another new sending unit from Carpenter. Dash gauge shows 30 psi. Checked oil pressure with a mechanical gauge and got 50 psi. Of course Carpenter knows nothing. Any ideas why the new sending unit only shows 30 psi at the dash gauge?


TomO    -- 05-01-2019 @ 9:34 AM
  Richard, I suspect that the reproduction sending unit is the variable resister type and not the King Seeley type. If you have the NOS one (check for KS stamped into the cover to make sure that it is the correct one), it can be repaired by one of the people that advertise in Hemmings. Bob's Speedometer may be able to do it.

See this E-Bay item for the stamp


37RAGTOPMAN    -- 05-07-2019 @ 8:43 AM
did you try grounding the wire going to the oil pressure sender and see if the gauge reads higher ? with the sender disconnected
IT MIGHT be as simple as a bad sender or corroded wiring , connections ?
hook up a mechanical gauge and run the engine and see what GAUGE reads,
before major work that may not be needed,
I bought a 8N tractor that had a bad gauge, I am sure the owner thought it needed rebuilding,
motor ran with no noise and gauge did not move, replaced gauge and never had any engine problems,
hope this helps.
my 2 cents 37RAGTOPMAN

GK1918    -- 05-24-2019 @ 5:18 AM
  I have posted this question too many times and no one has the answer.
All those oil gauges are marked 0 30 80 I am bad at math, but
ain't half of 80 40? My car hot idle, says 30 and my mechanical says 40:
If I move the car even a foot, dash gauge says like 35 and mechanical shoots
to 60 , so what was King Seeley thinking? Ideas any one cause
I don't and I have 5 F6 V8 trucks 2 F8 V8 337s all read the same so its not
senders or the gauges and my every day driver 46 Super Deluxe 59A V8.
And then who has ever had the temp gauge read correctly besides never?


37RAGTOPMAN    -- 05-24-2019 @ 7:18 AM
  try to
disconnect the wire going to the sender,
and try grounding the electric sender wire to ground,? to see what the gauge does,

I think it should read the highest it can,
if not your gauge is not working correctly
these are not great instruments, that's why the went to warning lights,
so not to alarm owners,
my 2 cents 37RAGTOPMAN
oil pressure relief valve also could be the problem with low oil pressure, broken spring, dirt in it,
might be a thing to check out, also a worn oil pump,

len47merc    -- 05-24-2019 @ 6:38 PM
  You guys are hijacking nuffsaid's thread. Best for both of you to start your own threads / posts.


51f1    -- 08-19-2019 @ 5:08 PM
  This is an old thread. I probably said the same thing above.

Regarding Senior's oil pressure problem: I had the same experience with a Carpenter sending unit. It reads a maximum of 30 psi. My old and failed NOS sending unit always read 50 psi as it should. I double checked with a mechanical gauge and got 50 psi. Carpenter doesn't have a clue as to the problem and really doesn't care. (I got another Carpenter unit. It also read 30 psi.) I use the new sending unit which shows 30 psi knowing that it is really 50 psi.

I had the same problem with a Carpenter temperature sending unit. It reads low, but I'm living with it.

Chinese junk, I'd guess.


This message was edited by 51f1 on 8-19-19 @ 5:20 PM

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