More Questions on Oil Pressure

After reading the last thread on Hot Weather and Oil Pressure, I got to thinking about how to prolong the life of the engine.

I am estimating some of these numbers, as I have the hood off at the moment for some painting.

It will get about 30-35 lbs. when running 7/8 throttle or more while it is cold.

After it warms up, it will get 20-25lbs. at 7/8 throttle or more.

In either case, it only gets about 5 lbs. at idle.

So would it be a wise thing to rebuild the oil pump at this point, just to see if the pressure will improve?

Just thinking that if it needs further work down the road, such as bearings and such, the pump will get rebuilt anyway. Just sounded like a rebuilt pump now might possibly solve the oil pressure for the time being.

Thanks,

Mark
 
(quoted from post at 13:09:02 09/02/13) After reading the last thread on Hot Weather and Oil Pressure, I got to thinking about how to prolong the life of the engine.

I am estimating some of these numbers, as I have the hood off at the moment for some painting.

It will get about 30-35 lbs. when running 7/8 throttle or more while it is cold.

After it warms up, it will get 20-25lbs. at 7/8 throttle or more.

In either case, it only gets about 5 lbs. at idle.

So would it be a wise thing to rebuild the oil pump at this point, just to see if the pressure will improve?

Just thinking that if it needs further work down the road, such as bearings and such, the pump will get rebuilt anyway. Just sounded like a rebuilt pump now might possibly solve the oil pressure for the time being.

Thanks,

Mark

Rebuilding the pump may get you better idle oil pressure but 20+ PSI at working RPM is not at all bad in this engine.

TOH
 
Mark........you do realize yer oil pump is part of yer #1-bearing cap, don't you? To gitt to yer #1-bearing, you haffta drop yer castiron oil pan. This is NOT a simple inplace repair. BIGGEST cause of low oil pressure is WORN engine crankshaft bearings. While Ford in 1939, specified 30wt detergent oil and 40wt for HOT weather operation; they also recommended adding a quart of kerosine for COLD weather operation. Modern MULTI-WEIGHT oil so much better. Me? I recommend 20-50wt oil. This is 20wt oil with temperature sensitive additives. You might also try 50wt RACING oil to improve yer oil pressure.

BTW, the change in oil pressure with temperature is NORMAL. Its called "viscosity factor". ........oily Dell
 
as dell said,

I had a tired old 4 banger jeep engine that ran fine, but had low oil pressure at idle.

old dude at the napa store told me to run 50 weight Valvoline racing oil in the old jeep.

was not hard to start and it kept the oil pressure up in the 20+ range when engine was warm and at idle.

engine ran for many years with Valvoline racing oil, that is great oil.

they use it in tight new hot rod engines, so its not like you think of, when you think high viscosity gear oil.

might be worth a try, all it would cost you is an oil change.

also, you might add one qt of lucas oil stabilizer to the current oil, if you are running 30 weight oil, I used that in my old ferguson for years.

but I have had better luck with shell rotella 15w40 diesel oil, diesel oil still has zinc in it to protect the bearings, I also add a qt of lucas oil stabilizer to the oil.

most all other oils: they have taken the zinc out of the oil (your epa at work).
 

If your clearances are excessive an oil pump that puts out advertised flow/pressure will only get you so far. An initial, less expensive, option may be to ensure you pressure relief valve is in serviceable shape. There are specs on the spring in some of the manuals.
 
(quoted from post at 13:46:37 09/02/13) as dell said,

I had a tired old 4 banger jeep engine that ran fine, but had low oil pressure at idle.

old dude at the napa store told me to run 50 weight Valvoline racing oil in the old jeep.

was not hard to start and it kept the oil pressure up in the 20+ range when engine was warm and at idle.

engine ran for many years with Valvoline racing oil, that is great oil.

they use it in tight new hot rod engines, so its not like you think of, when you think high viscosity gear oil.

might be worth a try, all it would cost you is an oil change.

also, you might add one qt of lucas oil stabilizer to the current oil, if you are running 30 weight oil, I used that in my old ferguson for years.

but I have had better luck with shell rotella 15w40 diesel oil, diesel oil still has zinc in it to protect the bearings, I also add a qt of lucas oil stabilizer to the oil.

most all other oils: they have taken the zinc out of the oil (your epa at work).

Zinc is not used for journal bearing protection which is provided by a layer of high pressure oil film. It is a boundary layer wear protection additive used for sliding parts like lifter feet and cam lobes which regularly run with full metal to metal contact .

TOH

PS> Appearances can be and often are deceiving. Most brands of SAE 50 motor oil have the same or higher viscosity than most SAE 90 gear oils.

SAE 50 engine oil viscosity specification: 16.3 to 21.9 cSt @ 100C
SAE 90 gear oil viscosity specification: 13.5 - 18.4 cSt @ 100C
 
(quoted from post at 13:56:24 09/02/13)
If your clearances are excessive an oil pump that puts out advertised flow/pressure will only get you so far. An initial, less expensive, option may be to ensure you pressure relief valve is in serviceable shape. There are specs on the spring in some of the manuals.

And what does that do to help the clearance problem? Running clearance in combination with engine speed and oil viscosity is what determines the thickness of the oil film inside the bearings. As clearances open up the oil film thickness is reduced - increasing pump pressure can't and won't fix that.

TOH
 
Thanks for all the replies.

As a rookie, I got the idea that the oil pump was in the vicinity of the governor, what with that oil line to the filter coming off the back of it. After looking at the Master Parts catalog, I now understand the situation better.

My oil pressure situation was greatly improved a while back when I changed out the 30W that was in it for some Castroil 20-50 that I had hanging around in the shop forever.

I may sort through the oil info and experiment with that on the next oil change. I need to short change for a while anyway to work out the sludge issue.

Thanks again,

Mark
 
The primary reason for low oil pressure on an engine at operating temperature at idle is bearing wear. I'd use a thicker oil until it was a good time to go through the engine.
 
(quoted from post at 11:10:47 09/02/13)
(quoted from post at 13:56:24 09/02/13)
If your clearances are excessive an oil pump that puts out advertised flow/pressure will only get you so far. An initial, less expensive, option may be to ensure you pressure relief valve is in serviceable shape. There are specs on the spring in some of the manuals.

And what does that do to help the clearance problem? Running clearance in combination with engine speed and oil viscosity is what determines the thickness of the oil film inside the bearings. As clearances open up the oil film thickness is reduced - increasing pump pressure can't and won't fix that.

TOH

Very good. You are so bent on arguing that you've failed to comprehend what folks are posting.
 
Nothing wrong with wanting more longevity and the right oil will help.
But remember you are dealing with an engine with 3 main bearings for 4 cylinders.
If you want more longevity get a tractor with Four main bearings for 3 cylinders.
Image is just one I grabbed off of google.

2452.JPG
 
Why would you go to the trouble of dropping the pan to get at the oil pump and not inspect "ALL" the crank bearings...

Any thing else is a hope and a payer your call your wasted time and money....
 
You have good oil pressures. I would not do anything unless you just want a look see. Would you believe that most idiot lights don't come on till your down to 7-lbs. Not much of seat time is done at idle speed and if ya really want to do away with 5 lbs at idle speed raise the idle up till its says 10-lbs wink! as Dell says.
 

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