HELP!!!!!! 1952 Super Cropmaster

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User avatar
prblake
Posts: 160
Joined: Wed Aug 25, 2010 1:52 pm
Location: Queensland, Australia

Cropmaster Oil pressure

Post by prblake » Wed Jul 03, 2013 7:51 pm

Stuart
In my opinion 15/40 is very light for an old engine like this and so I suspect you will see some small improvement in the pressure. Certainly worn main bearings will be the main cause of low oil pressure. It could possibly be caused by worn rocker bushes as well. You can temporarily block the supply of oil to see if this improves the pressure. There is a banjo fitting with a pipe to the rockers which you can block with a bolt in place of the banjo bolt but dont run it for any significant time in this form -just long enough to see if it lifts the pressure.
At least the 15/40 will have given it a clean out.
Is 15 psi to low? My Croppy is on loan to a local museum at the moment so I cannot check what it runs at but I think mine runs at about 15psi idling rising to 25psi when working. My Handbook says that when new the pressure relief valve let go at 30psi.
Perhaps anothe forum member who has there croppy nearby can tell us what pressure she runs at.

Paul

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db2d
Posts: 2198
Joined: Fri Feb 24, 2012 10:01 pm
Location: Monmouthshire

RE: Cropmaster Oil pressure

Post by db2d » Wed Jul 03, 2013 9:31 pm

The oil pumps were set at the factory to 50 lb.psi, cold.
The oil pressure should be 15/20 lb per.sq.in. at 600 r.p.m and 45 /50 1,800 r.p.m.(hot)
If the oil pressure is below 15 lb p.s.i (hot) the engine should not be worked

Guest

RE: Cropmaster Oil pressure

Post by Guest » Wed Jul 03, 2013 10:43 pm

It won't make any difference how the pump is set and you must remember it's probably had a bit of wear in it's life, it's the grade of oil that you put in the engine that matters in this instance and the operators handbook recommends straight 50.

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db2d
Posts: 2198
Joined: Fri Feb 24, 2012 10:01 pm
Location: Monmouthshire

RE: Cropmaster Oil pressure

Post by db2d » Thu Jul 04, 2013 7:39 am

In this instance the first thing is to check that the cork seal is fitted correctly before oil and oil pressure issues.

Guest

RE: Cropmaster Oil pressure

Post by Guest » Thu Jul 04, 2013 8:42 am

Bit of a 'chicken and egg' issue here. do you tear the engine apart to check the crank cork or do you put in a straight 50 oil to see if the leak stops or run the tractor for some time to see if the corks eventually swell enough to seal?

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stuartyd11
Posts: 71
Joined: Tue Jun 25, 2013 9:33 pm
Location: Scotland

RE: Cropmaster Oil pressure

Post by stuartyd11 » Thu Jul 04, 2013 2:09 pm

Thanks to all who posted replies.

I have removed the sump and had a check of the cork seals as i was draining the old oil out anyway. To me they seem to be seated okay under the main bearing caps. I intend to fit a new engine breather on the rocker cover and try the 40/70 in the engine to see what effects this has.

The tractor has never been worked hard since i've restored it the farthest its been has been up and down the road and ran for a max of maybe 10 mins. Since the engine hasn't been ran enough to really warm up i can't really say that the pressure does or does not rise. It sat steady at 15 lb psi at idle when running on 15/40. When I change the oil i'll take it a good run and get it warmed up.

User avatar
stuartyd11
Posts: 71
Joined: Tue Jun 25, 2013 9:33 pm
Location: Scotland

RE: Cropmaster Oil pressure

Post by stuartyd11 » Fri Jul 05, 2013 2:39 pm

Put the new oil in today and ran the engine and it is not good news. The oil pressure bearly moved off the stop when idling and struggled to reach 10 lb psi at full throttle. This was all done cold as i switched off before i let it get too hot as was worried i would start to do damage.

Any suggestions would be appreciated

Stuart

User avatar
prblake
Posts: 160
Joined: Wed Aug 25, 2010 1:52 pm
Location: Queensland, Australia

Oil pressure Cropmaster

Post by prblake » Sat Jul 06, 2013 3:35 pm

Hmmm This seems very strange. My first thought is can we trust the gauge given the history of the tractor? Can you swap it temporarily for another gauge to eliminate this option?
Next is the wire strainer on the base of the pump clean to allow oil to reach the pump? I note that you had the sump of so I am hoping you checked and cleaned the wire strainer at that time.
Low oil pressure is often associated with badly worn bearings but with the extremly low pressure you are describing I would suspect (in order)
-faulty gauge
-blocked strainer
-faulty pressure relief valve in the base of the pump
-worn pump gears etc
There is also a pressure relief valve on the input side of the oil filter which is designed to open when the paper oil filter blocks up and the feed pressure reaches 15psi. if this is not working then this could cause a low reading at the gauge.

You said that with the old oil it had 15psi at idle and now virtually none with the heavier oil. The only thing that this outcome would seem to logically relate to would be a blocked strainer.
Paul

Guest

RE: Oil pressure Cropmaster

Post by Guest » Sat Jul 06, 2013 4:14 pm

I would agree with you Paul, the thinner oil giving a higher pressure reading that the heavier grade would indicate a flow of volume issue which, narrowing it down, indicates a worn pump or a partially restricted gauze strainer basket. If the engine has been dismantled I would also check that the oil pipes to and from the pump were connected up properly and not leaking off.

User avatar
stuartyd11
Posts: 71
Joined: Tue Jun 25, 2013 9:33 pm
Location: Scotland

RE: Oil pressure Cropmaster

Post by stuartyd11 » Tue Jul 16, 2013 4:47 pm

Hi all, been having a head scratch about this and i came up with a similar answer to Paul. The other thing which springs to mind is that since it's a gear driven pump is it possible that it needs to be primed?

I checked the strainer at the base of the pump when i had the sump off and it seemed clear. My pump is the kind with only one oil pipe and i made sure the pipe was tight. The gauge is new but i will dig out another unit and give this a try before i get drastic and drop the sump off again.

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