High oil pressure?

Kenster

Member
52 8N.

When I first start it up, the oil pressure gauge shows right at 60 and stays there for a while. After I've worked it for a while (half hour shredding, for example) I notice that it has settled at 40 and stays there.

Are these numbers okay and is there something I should worry about?
 
I would remove and clean the pressure relief valve or try a different gauge. but it should not be that high and I don't like things that are not normal. it could be the sign of a blocked oil passage and that would not be good!
 
Kenster,Check your gauge readings with a known good gauge.If pressure still shows high 60 psi or more someone may have stretched or replaced the bypass spring with one that is to stiff.
 
(quoted from post at 12:11:38 08/02/14) 52 8N.

When I first start it up, the oil pressure gauge shows right at 60 and stays there for a while. After I've worked it for a while (half hour shredding, for example) I notice that it has settled at 40 and stays there.

Are these numbers okay and is there something I should worry about?

Only slightly higher than my 8N which "pegs" the 50 PSI gauge at startup. Cold oil pressure of 60 PSI wouldn't concern me but if you are just looking for something to do you can check the relief valve spring ;-)

Spring tension specification: 44-46 ounces @ 1.4" compressed length.

TOH

PS> If you are looking for an intellectual challenge using that specification and the diameter of the relief valve port you should be able to calculate a pretty good approximation of the cracking pressure. AFAIK that number was never published by Ford or any other source I can find.....
 
i'd always check an unknown gauge against a known one to verify.

oil type will make a difference.

60 psi is on the high side for what that engine should make in great condition. however thick oil, cold throttle, and it's not unbelieveable..

if the oil gauge checks good and you are using something like 20w50 or straight 50.. etc.. or 40.. I'd drop the oil to a 15w40
 
It's been like this since I got the tractor almost eight years ago. I never have to add oil. No leaks.

10W30 oil. Texas heat.

I'd rather not mess with it as long as it is coming down to 40 pretty soon. I tend to screw things up with I fiddle around.

Unless you guys think there is imminent danger of catastrophic failure...
 
Kenster Run her!It should last many more years.Better a little high oil pressure than not enough.
 
if you verified the gauge was good when you got her.. i'd probably run her.

i verify the oil gauge on any tractor i buy.

i have seen gauges that show 35 when they only are getting 15.

then again.. i have seen gauges show 12 and getting 30!!
 

How do you verify the gauge? If I install a second gauge and there is a considerable discrepancy, which one do I believe? Or should I try a third one?
 
if testing with a second gauge shows same pressure.. very good chance they are correct. if they show different pressure.. then you KNOW one of them is wrong.

If you have other equipment you can rotate that gauge thru.. once you get a gauge to agree with 2 others.. you know it is reading more or less accurately.
 

Well, I just had a thought... My oil pressure gauge reads up to 80lbs. Might it be the wrong gauge for a 52 8N? Everything I see for sale for an 8N is either 40 or 50lbs.

So, on an 80lb gauge it reads 60 at start up and settles to 50 after warm up. How would that translate on a 50lb gauge?

Doing the math shows that 50 out of 80 equals about 31 on a 50 lb gauge. That would be more in line, wouldn't it?

Or am I looking at this all wrong? If the ratio is the same, I can live with it and would rather not replace the gauge.
 
(quoted from post at 03:03:35 08/03/14)
Well, I just had a thought... My oil pressure gauge reads up to 80lbs. Might it be the wrong gauge for a 52 8N? Everything I see for sale for an 8N is either 40 or 50lbs.

I replaced a non-working gauge on my 8N (from this site) with a 50 lb. gauge. It pegs it at start up but drops to about 25 when warm. I'm thinking the 80 lb. one might have been better to have. My 9N has an 80 lb. gauge, appears to be original but who knows. It runs 25 at start, dropping to 15-20 warm.
 
(quoted from post at 22:03:35 08/02/14)
Well, I just had a thought... My oil pressure gauge reads up to 80lbs. Might it be the wrong gauge for a 52 8N? Everything I see for sale for an 8N is either 40 or 50lbs.

So, on an 80lb gauge it reads 60 at start up and settles to 50 after warm up. How would that translate on a 50lb gauge?

Doing the math shows that 50 out of 80 equals about 31 on a 50 lb gauge. That would be more in line, wouldn't it?

Or am I looking at this all wrong? If the ratio is the same, I can live with it and would rather not replace the gauge.

There is no ratio. Both gauges read pressure directly. A 50 psi gauge just gives you better resolution at lower pressures. Everything I've ever read says 50 is the maximum if the pressure relief is working properly which would make the 51-80 range useless on your gauge.
 
Not useless because it is an indicator of excessive pressure, suggesting as has been pointed out, potential blockage.
 
(quoted from post at 23:38:00 08/02/14) Not useless because it is an indicator of excessive pressure, suggesting as has been pointed out, potential blockage.

Not really. Assuming the gauge is accurate (big assumption) what it [b:22544bdc79][u:22544bdc79]positively[/u:22544bdc79][/b:22544bdc79] indicates is a pressure relief valve that is set at 60 PSI. The purpose of the pressure relief valve is to LIMIT the pressure at cold startup. In a fresh and normally functioning engine that pressure is reached and exceeded every time you start it. It isn't caused by a blockage - it is caused by heavy cold oil that doesn't flow through tight bearing clearances as readily as it does when it is hot. If the pressure relief valve is cracking at 50 PSI as it "should be" a blockage will not produce a gauge pressure of 60 PSI because the valve will relieve it at 50 PSI. My 8N [u:22544bdc79]pegs[/u:22544bdc79] the 0-50 PSI gauge at cold startup and I have no idea if the relief is opening at 50 PSI or not. And I don't care.

But if you do care I'd put my money on one of the following causes in the following order:

1) A gauge that is reading high
2) A pressure relief valve that has a cracking pressure of 60 PSI.

Both are easily checked. Verify the gauge reading. If that is correct you have a pressure relief set at 60 PSI. IMO there is nothing wrong with a relief pressure of 60 PSI - many engines run that high or higher. But If you still want to verify flow through the main oil galley pull the line off the oil filter. If you have oil flowing out it the main galley is not blocked. If you still aren't satisfied and are concerned about a blockage in one or more of the branch galleys and want to check that you are looking at a tear down.

TOH
 
(quoted from post at 23:38:00 08/02/14) Not useless because it is an indicator of excessive pressure, suggesting as has been pointed out, potential blockage.

You're right, of course. I should have qualified my response by adding "if the pressure relief is working properly".
 
(quoted from post at 09:13:07 08/03/14)
(quoted from post at 23:38:00 08/02/14) Not useless because it is an indicator of excessive pressure, suggesting as has been pointed out, potential blockage.

You're right, of course. I should have qualified my response by adding "if the pressure relief is working properly".

Once again I ask. If "the pressure relief is working properly" how does a blockage create excessive gauge pressure? Keep in mind the gauge is at the very end of the main oil flow and the relief is just above the pump outlet.

TOH

:oops: Never mind - I see your initial comment was that the 50+ end of the gauge is useless "if the pressure relief is working properly". Absolutely correct and I should reread posts before shooting from the hip - DOH
 
run it
I had a 46 2N that had your exact numbers, pegged at startup,
about 40 when warm. great engine, oil even stayed clean a long time.(should have kept at least that motor)

I work on a lot of tractors that have no numbers at all on the gauge.
What the gauge is doing is more important.
The percentage of needle drop when warm is what you watch for.

And with some of these tired old tractors, if the needle moves at all when you start it.....hurray, some oil movement.
If it stays off the left peg when warm....hurray...run it.

funny about oil pressure..I have a little more modern tractor with an oil idiot light. I like gauges, so I put one on and run both.
Motor is a little tired. O-P starts out very high and drops steadily when warm. Hot, on the gauge, very low.
The idiot light sender is good and the light goes out when you start it, and stays out when running.
Without that added gauge, I'd never know how low it was getting.
Ignorance is bliss, and probably one of the reasons factories
switched to lights :D
(check out some of the specs of idiot light senders. If we saw that low of a pressure on a gauge, we'd probably shut the engine down in a panic)
 
(quoted from post at 14:14:46 08/03/14)
(check out some of the specs of idiot light senders. If we saw that low of a pressure on a gauge, we'd probably shut the engine down in a panic)

Idiot lights are used because:
  • [*:aa77a9aa33]The light signals a "catastrophic" situation where major engine damage is imminent. When that light comes on you better shut the engine down immediately and correct the problem[*:aa77a9aa33]Most people do not know how to interpret the data provided by a gauge. They think pump oil pressure translates to oil film thickness inside the bearings - e.g higher oil pressure produces a thicker oil film and reduces bearing wear. It doesn't[/list:eek::aa77a9aa33]TOH
 

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