Forson Major Oil Pump

[Tjibbe]

I removed the sump - and have a few questions
Does it make sense to overhaul the oil pump - new one seems quite pricey ?
Strainer basket was lying on sump bottom - what keeps strainer on the vertical pipe ?
Front and rear crankshaft seals in sump look the same ? - gasket kit confuse me

[Timeee]

Dear Tjibbe

Replace oil pump? It depends on why you took the sump off in the first place. Was it because your oil pressure was low, the bearings were knocking, or oil pressure dropped drastically when the engine was hot? Have you taken off a big end bearing or a main brg to see what state the shell bearings are in? I think if you look back in the forum, you will see there are those who have run their engines on for years, with relatively low oil pressure. If the bearings, or crankshaft is worn badly, a new oil pump will not cure the problem. You could dismantle the pump and see whether the rotors are badly worn, or the oil pump body is worn.

Oil Strainer/sump screen. Prior to engine no 14225097, the sump screen was bowl shaped and held inside a pressed steel cover. After this, the sump screen was changed to a simple cylindrical type, with no cover, which is probably what you have. It is retained by two bayonet type lugs on the oil pump suction pipe. There should be a spring against which it is held securely. You fit it by inserting the "basket", which has 2 corresponding slots cut into it over the lugs of the pipe and turning through 90 degrees to lock it.

Rear and Front Oil Seal Packings. Depends on the quality of your gasket/seal set. From memory, sometimes the gasket supplier just provides a length of packing and you use it on edge for the 2 rear ones (upper and lower) and on its flat for the front one. I could be wrong on that, I have done a few other types of engine since rebuilding my NPSM some years ago and my one active brain cell has problems accessing the databanks nowadays. The packing should be trimmed to protrude about 15 to 25 thou (sandths of inch) after fitting.

Hope that may be of some help. I am sure someone else will chime in to fill in any gaps I may have left.

Regards Tim E

[Tjibbe]

Hi Tim,
I am restoring the tractor, and the thick oil sludge coming out the drain plug worried me. That is why I decided to drop the sump.
Yes it is a bowl shaped strainer inside a bowl shaped pressed steel holder. The holder has a round hole at the top.
Perhaps I should post photos of the gasket options inside my "gasket kit"; then I will better understand the responses.
Appreciate your help.
Tjibbe

[Timeee]

Dear Tjibbe

So you have the early type oil pump screen. I haven't come across one, so I am going by the repair manual. There should be a spring above the screen cover on the delivery pipe to the oil pump. The filter screen (basket) is held into the cover by a screen retaining clip which goes underneath it and clips onto two lugs in the bottom of the screen cover. I suspect that this just rests on the sump, so when you take either the sump, or the cover plate off, the whole oil pump screen assembly will drop off the pipe. Perhaps someone with detailed knowledge of earlier engines will know for sure, but it must make replacing the sump with the oil pump screen being held in the correct position quite tricky. Perhaps that was why they had a smaller cover plate (6 bolts), so you just had to offer that up with the screen delicately balanced on top. Hmmmmmm.

Regards
Tim E

[Tjibbe]

Tim ;
Agree - this is about my thinking as well.
The pipe does have a spring round it - purpose of which is then not clear.
Regards
Tjibbe