Low oil pressure

Farmall Cub Forum -- Questions and answers to all of your Cub related issues.

Moderator: Team Cub

Forum rules
Notice: For sale and wanted posts are not allowed in this forum. Please use our free classifieds or one of our site sponsors for your tractor and parts needs.
10+ Years
10+ Years
Posts: 145
Joined: Mon Feb 02, 2004 7:05 pm
Location: Brookfield Nova Scotia

Low oil pressure

Postby Maritimer » Thu Nov 25, 2004 10:40 pm

I put another motor in my cub. Works fine, no oil burning or ticks, but also very low oil pressure. I have lots of pressure for the first 5 minutes, after that it starts to drop. I put new oil filter and another gauge but it didn't change things. My next step would be to put new main bearings in it.would I need to put new rod bearings in it also. It would probably be a good idea. Would this cure the problem? There is no blow by so I'm not going to change the rings or fiddle with the valves. I don't want to take the motor out so I'll just drop the pan and do it from there. Is this a good idea?

My dad once told me if it wasn't for bad luck......I wouldn't have any luck at all......

User avatar
John *.?-!.* cub owner
Team Cub Guide
Team Cub Guide
Posts: 22627
Joined: Sun Feb 02, 2003 2:09 pm
Zip Code: 63664
Tractors Owned: 47, 48, 49 cub plus Wagner loader & other attachments. 41 Farmall H.
Location: Mo, Potosi

Postby John *.?-!.* cub owner » Thu Nov 25, 2004 11:38 pm

You won't care for my answer, but if this is a tractor you intend to use and keep for a while I would either borrow a micrometer or take it someplace that can mike it. If the bearings or that badly worn the chances of the crank needing to be ground are very good. I would also go with rod bearings too.
If you are not part of the solution,
you are part of the problem!!!

User avatar
10+ Years
10+ Years
Posts: 146
Joined: Mon Aug 02, 2004 11:31 pm
Location: Illinois

Postby nosih » Thu Nov 25, 2004 11:44 pm

Also, don't forget to replace the oil pressure regulating valve & spring. Two inexpensive items that can help quite a bit where oil pressure is concerned.

10+ Years
10+ Years
Posts: 80
Joined: Sat Feb 08, 2003 11:23 am
Location: Columbus, Georgia

Postby Ron » Fri Nov 26, 2004 10:06 am


I had one like this one time and this is what I did.

I dropped the pan and used plasti-gauge to check the clearance's on the mains and all of the rod bearings.
This is a cheap way to see the condition of the crank and how much clearance exist.
If you need to tighten it up a little, you can maybe find some .001 or .002 undersize bearings.

This can be done with the engine in the tractor.

1951 Farmall Cub

Team Cub Mentor
Team Cub Mentor
Posts: 16797
Joined: Fri Jul 02, 2004 9:52 pm
Zip Code: 65051
Circle of Safety: Y
Location: Mo. Linn

Rod and main journals

Postby Eugene » Sat Nov 27, 2004 9:16 am

Question. Does, did IH stamp their part numbers on the back side of the rod and main inserts?

Allis Chalmers stamped their part numbers on the back of their main and rod inserts. This makes buying the correct replacement inserts quite simple. You plastigage the journals, checking for clearence and taper. You then cross reference the old insert part number to find out the journal size.

Allis also placed shims between the journal base and cap. With the new insert in place you plastigage then add or remove shims to obtain the proper clearence. A very nice feature.

Question. Cam bushings. Cub engines - Do the cam bushings need to be replaced when you replace the rod and main bearings? On Allis engines the oil is first feed to the cam bushings then to the rod/main bearings. Worn cam bearings result in a loss of oil pressure.

  • Similar Topics
    Last post

Return to “Farmall Cub”

Who is online

Users browsing this forum: Don McCombs, Jim Becker, newtattoobob and 4 guests