Ford 8N high oil pressure

[HUTCHAMUSPRIME]

The other day my 52 side mount 8n oil pressure dropped down and I changed the oil, it was time anyway. It was down low, but still running fine. I changed the oil, replaced the filter, and now the pressure is pegged out at 80. I haven't ran it except to move it out of my way real quick. I've tried reading through some older forums and a lot of people say to just run it but I'm concerned with the sudden spike. Also a drop of oil seems to squeeze through the filter canister if I run it for a minute. I'm not sure if this is from the excessive oil pressure or the seal. Any ideas?
I just run out and test it does drop to about 58 at low idle.

 

[TractorTech]

I wouldn't run it either as it will develop leaks such as the filter housing. You could try removing the filter and try that. Otherwise, there is something lodged in a passage or on the relief.

 

[John0829]

I would take another known good gauge and test the pressure.

 

[Roadworthy]

Are you sure you used the correct viscosity of oil? Given the age of the tractor and the fact it's probably a gasoline engine 30 is probably the proper weight. If that's correct, I agree with John - put a known good oil pressure gauge on it. If that reads high, too, your oil pressure relief valve is not doing its job.

 

[HUTCHAMUSPRIME]

Are you sure you used the correct viscosity of oil? Given the age of the tractor and the fact it's probably a gasoline engine 30 is probably the proper weight. If that's correct, I agree with John - put a known good oil pressure gauge on it. If that reads high, too, your oil pressure relief valve is not doing its job.

I ordered a whole new set of gauges I was missing a tach anyway. Gonna swap them out and see what it reads. They should be in tomorrow night.

 

[HUTCHAMUSPRIME]

update:
New oil gauage only goes to 50 and it's pegged out at half throttle. I pulled the oil pressure relief to visually inspect it but I can't really tell much. I'm gonna replace it and see what happens. Any other way to test it?

 

[HUTCHAMUSPRIME]

I wouldn't run it either as it will develop leaks such as the filter housing. You could try removing the filter and try that. Otherwise, there is something lodged in a passage or on the relief.

I pulled the filter and got no change.

 

[EdGooding]

You said that you pulled the oil pressure relief valve and looked at it. How about the spring? Some folks have been known to stretch that spring or replace it with a heavier one to gain better oil pressure, sometimes to help sell the tractor. If the spring is too stiff, it won't allow the high oil pressure to open the valve.

 

[HUTCHAMUSPRIME]

You said that you pulled the oil pressure relief valve and looked at it. How about the spring? Some folks have been known to stretch that spring or replace it with a heavier one to gain better oil pressure, sometimes to help sell the tractor. If the spring is too stiff, it won't allow the high oil pressure to open the valve.

I couldn't really think of a "scientific" way to test the spring. It felt like a spring, it didn't seem overly difficulty to get the part back in place. If the spring is weak it would keep the valve open and I would have low oil pressure right? I have ordered a new replacement set for that just because I felt like it would be worth it. Swap with a known good one when I can't test the other. The only thing of note I could say is that you could tell on the little plunger surface that it had an area that looked more worn than the rest of it.

 

[John0829]

To check the relief spring tension, it should be between 44 and 46 ounces when compressed to 1.4".

 

[HUTCHAMUSPRIME]

To check the relief spring tension, it should be between 44 and 46 ounces when compressed to 1.4".

I'll just throw in the new one when it gets here.

 

[HUTCHAMUSPRIME]

I also did crack all the fittings and see that oil is flowing everywhere.

 

[John0829]

Just curious what weight oil did you put in it?

 

[HUTCHAMUSPRIME]

Just curious what weight oil did you put in it?

She'll rotella 15 40 that's what folks around me run, this is in SC. You think that's too heavy of an oil?

 

[EdGooding]

She'll rotella 15 40 that's what folks around me run, this is in SC. You think that's too heavy of an oil?

I run 15w-40 Rotella in my '52 8N year-round here in Virginia.

 

[John0829]

No 15w40 is not to heavy, I was just wondering that's all. Just for giggles take the relief plunger out of it and see what pressure you get, it could be that when you changed the oil a bit of debris got past the plunger and plugged up the passage. Yes I'm reaching here but knowing the design of the oil system of the N' tractors it's hard to come up with good reasons for the sudden high pressure.

 

[HUTCHAMUSPRIME]

No 15w40 is not to heavy, I was just wondering that's all. Just for giggles take the relief plunger out of it and see what pressure you get, it could be that when you changed the oil a bit of debris got past the plunger and plugged up the passage. Yes I'm reaching here but knowing the design of the oil system of the N' tractors it's hard to come up with good reasons for the sudden high pressure.

This is probably a stupid question but if I run it without the relief the relief plunger in, oil should come out right? If it doesn't, then the passage would be clogged right?

 

[John0829]

Yes, with the plunger out it should dump the oil out the bypass passage, just be clear remove the spring and plunger but put the cap back on. Don't worry if the engine has zero pressure for a few minutes at idle, the N engines can and have run on as little as 5 lbs. at full load for years.

If the pressure does not drop then it is a blockage in the bypass passage, I don't really think this is the problem but it might help point toward something else.

 

[HUTCHAMUSPRIME]

Yes, with the plunger out it should dump the oil out the bypass passage, just be clear remove the spring and plunger but put the cap back on. Don't worry if the engine has zero pressure for a few minutes at idle, the N engines can and have run on as little as 5 lbs. at full load for years.

If the pressure does not drop then it is a blockage in the bypass passage, I don't really think this is the problem but it might help point toward something else.

This works put because the new one came in over the weekend so I'll be there anyway and I can test it real quick. So with the cap on but the plunger and spring out the oil pressure should be low because the plunger isnt there restricting the flow ie raising pressure. So if the pressure is still high with the spring and plunger out then we have a blockage somewhere more than likely that's raising the pressure?

 

[HUTCHAMUSPRIME]

This works put because the new one came in over the weekend so I'll be there anyway and I can test it real quick. So with the cap on but the plunger and spring out the oil pressure should be low because the plunger isnt there restricting the flow ie raising pressure. So if the pressure is still high with the spring and plunger out then we have a blockage somewhere more than likely that's raising the pressure?

Well just opened up the package from aftermarket reliable and of course they forgot to send the oil pressure relief valve kit atleast I got the new tachometer cable lol.