Oil pressure drops after thirty minutes Ford 8N

[chas1100]

Oil pressure about 45 lbs on start up but drops to nearly zero after 30 minutes of mowing. Relief spring has been changed with only a small increase in pressure at start.

 

[Roger in Iowa]

Oil pressure about 45 lbs on start up but drops to nearly zero after 30 minutes of mowing. Relief spring has been changed with only a small increase in pressure at start.

What weight oil are you using and when last changed?

 

[Jim L WA]

Worn out t engine components. Bearings, rod or main, cam shaft journals, oil pump. Time for a tear down.

 

[chas1100]

Worn out t engine components. Bearings, rod or main, cam shaft journals, oil pump. Time for a tear down.

Thanks, I'm an amateur but I don't understand how clearances would charge so much and take 30 minutes?

Cheers

 

[chas1100]

What weight oil are you using and when last changed?

Thanks for the reply. 20-40 less than 25 hours but more than a year.
Cheers

 

[KCTractors]

Oil pressure about 45 lbs on start up but drops to nearly zero after 30 minutes of mowing. Relief spring has been changed with only a small increase in pressure at start.

I have a 8N that I use occasionally for a hour or so at a time, no heavy pulling. It starts with maybe 10 lbs of oil pressure and goes down to almost nothing. I have been running it that way for probably five years and it just won't quite. It smokes like hell but always starts even in the cold Wisconsin winters. If it dies, I think I'll keep it just for a conversation piece. The tractor doesn't owe me nothing. I have duals on the rear and I use it to freeze the marsh up so that I can get my JI Case 530 CK to the other-side of the woods to make firewood.

 

[Btzj02]

My 8N51 pegs the oil pressure meter at start. After the engine is warm it maintains 30 PSI at working RPMs. Once warm I have to be careful not to let the engine idle because the oil pressure than drops to almost zero. I realize I need to get in there and work on the engine but my attention has been diverted to another project till spring!

 

[Cliff (VA)]

Thanks, I'm an amateur but I don't understand how clearances would charge so much and take 30 minutes?

Cheers

The oil pressure drops for 2 reasons. The first is the oil has gotten hot (during the time delay) and therefore has less viscosity. The second is that engine components are worn and there are larger passages for the oil to pass through.

Cliff(VA) now NC

 

[Eman85]

Any chance the 70yo oil pressure gauge is tired? oil pressure isn't as big of a deal on these engines, no hydraulic valve lifters and not high RPM engines.