Oil pressure 46 2N

[Tom Beddard ENC]

46 2N Changed oil, used 40W,now have only 20lb @ WOT & about 5lb @ 1/2 throttle & 0 @ idle. Once it reaches operating temp these #'s drop. The #'s were a little better before change. I know the oil pump was rebuilt, new sleeves, pistons & rings & block sealer was done by Daddy in '84 & I'm sure the tractor was used only sporadically for maybe 10 yrs & then only blade work or a dirt scoop. I don't know if any more was done in the engine at that time. I have not replaced the OP gauge yet as it seems to be working. I reprimed the oil pump, but no change. The tractor will only be lightly used because we have a 4000SU I use for heavy work. Should I use some of the Lucas or STP products, a heavier wt oil or what ? Thanks
 

[TheOldHokie]

[Tom Beddard ENC]

Not what I wanted to hear but what I expected to hear. Should I park it now or run it til it makes no OP at any RPM?
 

[Tom Beddard ENC]

Just to be sure I'll get a new OP gauge tomorrow. Thanks TOH
 

[HCooke]

Change the oil gauge first. I would not run it until it reads 0 psi. That could cost you more money to fix it.
 

[Fritz Maurer]

Overhauled in '84 and used the way you say it has, it should be barely broken in. I'd check the oil pressure regulator spring.
 

[Bill Rowles]

If the gauge and oil pressure relief vlave and spring check as OK, I would check the oil pump suction line braze/solder joint for a possible air in-leakage problem.
 

[TheOldHokie]

[CharnerL]

You said you changed oil and after that, oil pressure was as stated. There is a possibility that when replacing the oil pan drain plug the plug could have made contact with the pick up tube and as you tighten it pushes the tube up. The slighest movement on the tube will break the seal at the pump and start drawing air and thus loss of pressure. Drain the oil and see if you can move the tube at all. If you can, thats your problem.
 

[jackinok]

a couple of times ive changed oil and started having these problems,once on a old pickup and once on a 8n. how much better was the oil pressure with the oil you were using? if it were just two or three lbs, i would just suspect your guage is reading different from the heavier oil.rebuilt almost thirty years ago it could be getting weak though.another thing i suppose it could be if its just a few lbs is maybe a more restrictive oil filter(?)