Farmall cub oil pressure

Tue Jul 16, 2013 12:41 pm

My friend that does a lot of work for me has a 48 Farmall Cub..He ask me to look at it yesterday so I loaded it up and brought to my house..Heres what I know, Has the engine completely overhauled yet when they started engine it had no oil pressure. They installed new cluth pressure plate and throw out bearing.
This tractor has been sitting now for a couple of years..I read a little on here last night and it says to prime the oil pump, Ive taken the allen head screw out and put 3 squirt cans of oil in it and started engine but no pressure,Shut it back down.How much oil should I put in this primer hole..Also Ive taken out the plugs and removed the pressure gauge and spun it over but never can get any oil where gauge was, What is my next step? May have bit off more than I can chew. What are anyone suggestions??

Re: Farmall cub oil pressure

Tue Jul 16, 2013 12:58 pm

Herbie:

McCormick Farmall Cub Operator's Manual 5-1-49

Image

GSS-1013 Engine Lubrication System

It really doesn't say how much oil to use in priming the pump.

Image to Farmallcub.com :big smile: Forum Family. And you have come to the right place for all things Cub related. If you click on the Site Rules, Regulations, & Important Information, it will point you to :arrow: the Welcome Wagon wherein you will find links to many useful sites and topics. One of the most important resources are Owner's Manuals, Parts Catalogs and Service Manuals. The Cub Manual Server is the home of the jpg versions and the PDF Manuals -- well the pdf's of course :wink: Enjoy!.

Re: Farmall cub oil pressure

Tue Jul 16, 2013 1:08 pm

Has it ever had oil pressure since the rebuild? If not there is a good chance one or more of the oil gallery plugs was left out during rebuild.

Re: Farmall cub oil pressure

Tue Jul 16, 2013 2:03 pm

Absolutely do not start the engine until you have the oil pressure problem figured out and resolved.

Allen plug on left rear of engine. Remove and install 1/2 cup heavy engine oil. Rotate engine by hand 1/2 revolution. Install another 1/2 cup oil. One more 1/2 revolution and install 1/2 cup oil. This will fill the galleries and put engine on into the main and rod bearings.

Couple easy areas to check. Under the valve tappet cover is an allen screw plug the stops off the oil gallery. Next area to check is the oil pressure relieve valve, right front of engine. See if both are installed. Next remove the oil filter top. Spark plugs removed, crank over engine to see in oil is entering the front inside of the oil filter housing.

Bad news if the problem is not disclosed in the earlier discussion. There is an allen screw plug under the cam shaft gear. This is the one normally left out during engine rebuild. This means pulling the engine, removing the engine front cover and oil pump to move the cam shaft forward enough to install the allen screw plug.

Re: Farmall cub oil pressure

Tue Jul 16, 2013 2:40 pm

Eugene:

herbiegrizz wrote:I read a little on here last night and it says to prime the oil pump, Ive taken the allen head screw out and put 3 squirt cans of oil in it and started engine but no pressure,Shut it back down.How much oil should I put in this primer hole..Also Ive taken out the plugs and removed the pressure gauge and spun it over but never can get any oil where gauge was, What is my next step? May have bit off more than I can chew. What are anyone suggestions??


Eugene wrote:Absolutely do not start the engine until you have the oil pressure problem figured out and resolved.

Re: Farmall cub oil pressure

Tue Jul 16, 2013 4:34 pm

UPDATE Took the plugs out and then removed the oil pressure gauge and the filter I spun the engine and oil came into reservoir for the filter. Put filter back in and spun engine and oil came out hole for gauge. Put gauge and plugs back in and started it up and no oil pressure on gauge. Im not sure its the right gauge. .I did run it for a few minutes and will check oil before proceeding

Re: Farmall cub oil pressure

Tue Jul 16, 2013 5:38 pm

You can test the oil pressure gauge with an air compressor, set on 25 or 30 psi - give or take.

If the oil pressure gauge tests out as working to any degree - suggest trying my previous suggestions.

Re: Farmall cub oil pressure

Tue Jul 16, 2013 6:34 pm

It will take several seconds for oil pressure to register on the gauge. You will never get it to register just cranking the motor over with the starter.

Follow the steps that Eugene outlined for the safest route.

Re: Farmall cub oil pressure

Wed Jul 17, 2013 4:29 am

If in the end you still do not have any oil pressure, but have oil flow to the filter housing, I am will to bet that when the motor was rebuilt they took out all the hex plugs to get everything clean and left one out. The one left out most times is under the front engine cover behind the cam gear. I am sure you can already guess how I know----and this leads into BOSS HOGS post about starting the engine and making sure everything is OK before the tractor is together and the painting complete. I am sure you can also guess how I understand that now too.

Re: Farmall cub oil pressure

Fri Jul 19, 2013 3:02 pm

Decided to start engine since I had oil coming into filter..Let it run a few mins and cut it off..Later let it run some more and shut it down and then started it right back up. I let it run 5 mins this time and it was running fine then quit like you turned key off..Put some more gas in it and it started back and run about 5 mins and died again.Its six volt system. Was ckecking it out and noticed they had negative ground..This cant be right..Tried to start back and it will spit and backfire. Tried to pull it off to start and it spits and backfires..Any suggestions .

Re: Farmall cub oil pressure

Fri Jul 19, 2013 3:44 pm

Cub 6v systems were delivered positive ground. Some hook up battery negative ground because that is what they are used to with more modern cars and trucks. It doesn't really matter a lot except in charging on a gen/cut-out or gen/reg system except that it may not charge. If the Generator was polarized that would take that problem off the table.

Sounds like you are having a spark issue. Could be coil .. could be loose wires. Check the magneto coil for a good blue spark and for each of the spark plug wires coming out of the cape. Check the spark plugs as well. If that is ruled out check the fuel supply.

Re: Farmall cub oil pressure

Fri Jul 19, 2013 4:11 pm

Rudi wrote:
Eugene wrote:Absolutely do not start the engine until you have the oil pressure problem figured out and resolved.
Oil flow does not equal oil pressure.

Now you need to determine why you have no oil pressure and check the condition of the rod and main bearings and crankshaft journals.

Re: Farmall cub oil pressure

Fri Jul 19, 2013 4:15 pm

I need to add that once it was running earlier today The amp ga didn't show a charge The battery is dead. .Ok if I were going to jump off from my truck do I need positive to ground to check spark

Re: Farmall cub oil pressure

Fri Jul 19, 2013 4:32 pm

The battery doesn't care what polarity the ground is. IF you were going to jump start it from your truck then you need to ensure that negative terminal is connected to negative terminal and positive terminal to positive terminal. However, be very careful .. jumping a 6v with a 12 volt can be pretty risky. Just touch the positive terminal.

And since you have had the engine running do you have oil pressure indicated? If not then the oil pressure gauge could very well be faulty. Check with a known good gauge.

Re: Farmall cub oil pressure

Fri Jul 19, 2013 4:40 pm

Still no pressure showing on the gauge After the initial startup for a couple of minutesrun time. I did shut it down and opened the valve on bottom of oil filter to make sure it had oil coming in... I just went to shop and popped the distributor cap to look inside..Looks like moisture and Several Big black ants lol Does the rotor button just pull off Guess iull look at points and condenser Man I hate working on someone elses machine and not knowing whats been done to it Im not good at it either.