low oil pressure in Y block

[djfordmanjack]

Guys, considering many things with the low oil pressure in my 57 292.

Has any of you ever found a clogged oil pick up sieve causing low pressure ?
I have replaced oil pump twice and had frequent oil and filter changes. engine has good performance and not much of any ticking noise which would indicate worn bearings. it is very dirty inside and clogged with the parafine type of mud. I have cleaned as much as possible form the valvetrain area. I wonder if much of the oil pan including the pick up could be full of mud ?
Has anybody found that problem before?
A friend of mine had nearly zero oil pressure on his 61 Nailhead, only to find out that they caved in the oil pan during transport. so his pick up area was very much restricted. all was well after straightening the pan. the Y block oil pan looks great from outside, but considering said problems.
Anybody Knows?

[hiball3985]

Do you have a gauge connected to get a reading as to how low it is? It is a possibility that the pick up screen could be clogged up some what. I've taken off old pans that are filled with sludge and the pick up also. The only correct way is to remove the pan. I've seen it done another way by draining the oil and filling the pan with solvent and letting it sit for a period of time, then drain and flush with some cheap oil and it worked. Another time I saw this method not work, the solvent loosened so much crap in the pan it didn't all get flushed out and ended up clogging the pick up. So that method is a roll of the dice! Pulling the pan you don't have much to lose, one gasket and a little labor.

[petew]

Sure , that could be that cause but so could a bunch of other things.
I have a 57 Country Sedan as well and I can tell you that it is not difficult to pull the pan down and in reality that would give you the answers to your questions.

My advise is take the pan down and inspect the pick up tube for blockage and cracks in the tube itself. While you are there pull one rod cap and check the upper bearing half for wear.
Check a main as well looking at the lower bearing half for wear.

I have changed rod and main bearings before with the engine in the car, no perhaps a textbook repair but it will give you your oil pressure back if worn bearings are the cause and again it's not difficult.

If you lived closer I would give you a hand but that Atlantic Ocean is big !

Pete

[djfordmanjack]

Thank you Jim and Pete ! lots of answer to my question and obviously only one way to find out. will pull the pan asap later in fall and check things. great tip to check the tube for cracks. The bearings will get checked in the process. Jim it has maybe 25 psi cold with 20/W50 grade oil and goes to nearly zero hot ( idle pressure). the old oil pressure ( idiot light) sender was faulty and would only flicker at 2-3psi ( I did a pressure test with a tire inflation gauge).  the NOS replacement switches at 6psi.
I already got good advice from Jay how to remove pan in car ( slightly lift engine and rotate crank in certain position to clear the pan on final removal).

[gasman826]

With the pump and plumbing being external, remove the tube and blow air through to remove screen blockage.  If oil pressure increases you will know there is trash in the screen.  If no improvement, something more serious.  Another concern with the external pump is the external tube.  If the external tube leaks, oil pressure is also affected.

[hiball3985]

I've removed several pans over the years and didn't have to raise the engine, Jay is right, the crank has to be in a certain position for the pan to clear the crank throws. Have you ever tried a lighter oil?
I never run anything higher then 10-30, heavier oil doesn't always equate to higher pressure. I'm more concerned with volume then pressure. Remember the factory spec for the Y was 20W.
Running newer detergent oils may have broken up a lot of sludge and I'll bet you find the pan full of that..

[Ray]

My decaying memory tells me that the primary cause of low oil pressure is generally due to worn cam bearings. That might be a good place to look.

[djfordmanjack]

Gary, I might do the screen cleaning with compressed air before pulling the pan to gain some more info, thx.
Jim, in general I have had good experience with the 20W50, especially concerning less leaks over a long period of being parked. At the moment I am running a gear type oil pump, that is completely overhauled (incl new check valve spring) and has tight clearances. I am sure that the engine is full of sludge and I remember on another 292 (I disassembled) the screen was partly clogged with sticky goo and stuff, even though the engine wasn't that dirty inside. I have that cleaned screen in hand and I must say it is quite fine mesh.
Ray, this is my most dreaded thought. worn cam bearings would just most likely mean pulling and completely tearing down the engine. Although I have every single part here for a full engine overhaul, I would rather not with this car at this point. I doubt that I could finish the job and having it rolling again in a year or 2 with all my other commitments. My first step will be a good evaluation of what the problem is about and obviously a pan and rod/main cap removal will be well spent time at this point. Thinking about it, tomorrow it's Sunday and still no obligations...hmmmmm.....

[Ecode70D]

Guenter
     You got a lot of good advice here.   I especially like what Gary said about blowing air down into the oil tube.  If the oil pressure increases you will know for sure what the problem is. In any event, you will eventually have to remove the oil pan in place. Prepare yourself now for the shock of your life when you get it off.  You are going to find a lot of sludge in that pan that you will have  to remove with a putty knife.  In the old days they used lots of strange additives like STP and it will be stuck in the pan. That stuff did not mix with the oil.  It went to the bottom of the oil pan and stayed right there.   Jay
       
     

[Lou]

Lets back up a second, what are you calling low oil pressure? At what RPM ?  Hot or cold?

[Tom S]

Lets back up a second, what are you calling low oil pressure? At what RPM ?  Hot or cold?

See the 4th post.

[djfordmanjack]

I have to correct those readings somewhat. Let me start with having hooked up an actual oil pressure gauge to the sender unit outlet.
When the engine is cold, in  70 degree weather I have approx 40-45 psi on startup and on fast choke idle. pretty fresh 20-W50 oil (less than 1000 miles). as soon as it gets off the fast idle and choke while the engine is warming up, it has approx 35psi at an estimated 600rpm in Neutral.
when the temp. gauge reaches the middle  ( which is approx 160F, according to an extra temp gauge I had mounted before and a pretty accurate reading) it has about 10 to 15 psi in idle, N.
after some 10 or 15 minutes of highway or downtown traffic it drops below 10 psi ( hard to read the gauge that low) with Drive engaged and at shy of 600 rpm, probably closer to 500. oil pressure increases to about 10psi in Neutral.
In a little warmer weather (80-90degrees) the oil pressure drops so much that the idiot light would flicker ( 4-6psi obviously, as per sender unit pressure test) in Drive and idle, but will go out when put to neutral.
After extended highway drive and engine temp up to 180 or 190 degrees after a sudden stop the idiot light would even come on and stay lit in Drive and low idle.
I have to mention that as soon as I start off in gear and reach maybe 10mph , it just takes a few seconds and the oil pressure goes up to 15 psi and driving at maybe 20 mph and in second gear it will climb to 25 psi quickly, even when hot.

I did drain the oil and visually inspected the pick up screen and it is free of debris and sludge. I had cleaned and flushed the engine both warm and cold with different oils and 'additives' before, several times. also changed the oil and filter 3 times. Probably washed out a lot of the old sludge before. it appears as if my problem is caused by worn out bearings.

[hiball3985]

I know you don't want to hear this  but think about which oil is easier for the pump to pump and force through the filter, 10-30 or 20-50? Which oil will drain back to the pan easier? Have you ever tried adding and extra quart to test if it isn't a drain back problem?

[rmk57]

  how many miles on the engine?  If you have 120,000, 30, 40 on it it's probably due for a rebuild or at least an overhaul with new bearings.

[djfordmanjack]

it is basically a one owner survivor car from of the SFB area, most probably has og to car speedo and odo working, just turned over zero recently.(could also be 200k miles). I believe it is the og engine to the car. all date codes, details match.
yes Jim I am giving your idea of lighter oil a thought, especially since you are very knowledagble about Y blocks and also drive yours in hot climate. it is also easy to see that lighter oil would increase the oil flow to the bearings.
yes I did try overfilling and no change in oil pressure. but the excess oil drained from the rear main seal as soon as the car was parked somewhat uphill for longer time. I now have it in the middle of the dipstick marks and oil loss has has become minimal, if any at all. no drips under pan when parked after driving some miles. sometimes there is a little drop of oil from the road draft tube. very minor.

I have a spare engine with all the parts needed for rebuild and it would probably be better to build this over winter and swap engines,if I had the time. probably not. I don't want to pull this engine in car for a rebuild, rendering the car undriveable for an extended time. we all know how that goes. you disassemble a car, and 5 yrs later the parts are still spread all over the place....not this time! 

this season will be over soon, so I am not in a hurry anymore. haven't driven it much unfortunately. I need to check my options right now. I have to say again and again that the engine is very powerful and does not smoke or burn oil except for the valve stem seals.

The more I think about it, the better this idea sounds: replace the valve stems, drop the pan and crank, and check/replace the main and rod bearings accordingly. AND use lighter oil !