G oil pressure regulating valve question

ps - I really don't want to remove the can if I don't have to - it didn't appear to be leaking before disassembly.

Thanks for a very informative dialogue as I to am contemplating low oil presure problems on our GM. The tractor had set outside and hand't run for about 5 years when I convinced my dad that we really aught to put the tractors in the shed. At that time it took about a half a day of tinkering to get the GM ready to start. Things like draining water out of the transmission and a fresh oil change oiling cylenders and getting spark. When we got around to starting it, it fired right up except for the indignity of having to be pulled by an Allis Chalmers half its size as the starter also didn't work. When it started it ran good and had good oil presure ( slightly above H on the gague ) but after it ran for about ten to fifteen minutes the presure dropped to where slightly above the L. At that time the objective was to get the tractor inside and since it still had enough presure to run I did just that. Its since been parked for seven years but at least its been inside.

I am finally getting to it, and started working on the starter last week. I plan to pull the top cover and as a mimimum clean the oil pump screen and wash the crank case down. When I last drained the oil, the oil at the bottom of the sump seemed gritty. The grit seemed little grains of carbon. my guess that they had flaked off while the engine was sitting. Any way your detailed discussion proves to be quite timely as I am hoping to pull the crank case cover this weekend to look around.

I too like G-man find it hard to figure how the regulator head and oil filter system work from pictures in I&T and the JD parts book.

So how does the JD oil system work? It looks me like the pump sends oil to the regulator head on the filter and from there the oil is distributed.

What is the oil flow path through the filter? Like where is the goes-into and goes-out-of ?

Is the oil filter in the full flow of the oil pump or is it just filtering the excess that is bypassed by the presure regulator?

Thanks and thanks for any additional information you may have to offer

D.D.Post

ps Dpost - while you have the crankcase cover off, I would check rod clearance and adjust as required - if it is excessive, it can cause low oil pressure. Spec is .002" to .004" - it's easy to check with plastigage. Also check the condition of the babbit in your rods and possible crank end play, etc. The I&T books do cover those procedures in a little more detail. Good luck with your GM - I hope to own one someday.

G-MAN, I really don't know how much distortion is too much. The more it's distorted the more apt the gasket is to blow out.
~New cans are hard to find & good used ones are hard to get out so no one likes to sell them to you.
~ I have straightened some with a hammer & steel shaft, I have pulled some cans to straighten in the press. If you have a distorted can & straighten it, you probably want to make sure you never overtighten the filter cover or it probably will bend easier the next time.
~Look at the attached picture closely & you can see the filter head sitting at a slight angle to the can. That head had a leaking gasket so you can see it doesn't take much.....