656 Low Oil Pressure after rebuild (like CJ 1080)

Like CH 1080 I also just finished a rebuild and now I have low oil pressure. My tractor has the c263 gas engine. What would normal oil pressure be on a fresh overhaul for this engine?

I replaced cam bearings, rod bearings, main bearings, rings, pistons, sleeves, and exhaust valves. All journals were within spec. Engine had 20+psi before rebuild; now it has about 12psi at 1500 rpm, 16psi at a little higher rpm, cold or hot. Running 15-40 Rotella (for low ash). Not getting a low oil pressure indicator light but I have no idea if that light

The oil pressure gauge is aftermarket. I replaced the plastic line that feeds the oil pressure gauge as part of the work I did on the tractor. works.

I used the black engine rebuilding lube that the gearheads at work recommended (vs. white grease.) Could this black stuff be plugging up the oil screen? I didn't go nuts with the quantity. I haven't dropped the pan yet. I didn't pull the oil pump apart when I had it out.

I called the place where I usually get my tractor parts to price a new oil pump but they said only used pumps were available.

Only oddity in the overhaul occurred at the machine shop. I watched the shop owner install the cam bearings and he misaligned one and had to eccentric the hole in the cam bearing a bit but I'm not seeing any way that small enlargement in the bearing thru hole would affect the oil pressure any. (Still, on any future engines I'm doing cam bearings myself, tool is only about $120 on Amazon)

What do you guys think? Should I try a different oil pressure gauge? Should I just use the tractor and not worry about it?

Put a reliable gauge on it first. Next go for the oilpump as noted in the other post. JimN

Which oil filter, pressue regulating base do you have. Did you repair or replace the springs and valve. We used to have a lot of problems with these pot medal filter bases and the valves in them. Early ones had a fiber disc which was very poor, and then they went to a medal one but you still had to be sure the seat was good. They also made stronger spring, and you should run about 40 psi at high rpms. Older model engines like on the 560 used a cast iron base with a plunger type relief valve and were much less problem. It a lot easier to check this item first but of course pump or other problems could exist.

As part of overhaul I pulled the oil filter housing apart to clean it and replace the gasket. I don't recall any fiber discs (so I guess I have the metal version.) When you talk about the 'seat' do you mean the part of the housing that the spring presses against?

What I am talking about is , under the spring there is a valve. You need to take the snap ring out that holds the spring in housing and check that valve is making a leak proof seat in housing. The valve may be a fiber disc or a metal one. It will be obvious to the naked eye if seat is good or not. Also, make darn sure gasket matches base as there are at least three different configuration of gaskets that usually come in a gasket kit. I just looked at the online parts book on CaseIH and they showed only the pot metal type filter base for a 656 so I am 99 percent sure that is what you have. A worn oil pump will usually give you pretty good pressure when cold but a leaking or weak regulator valve will not. Another thing, you need to make sure correct spring is installed on regulator as the other spring is a filter bypass valve and much weaker. Known correct gauge also of course. If you haven't, take a look at the parts manuals available on CaseIh site, for model you need to put in C-263 as the engine manual is seperate from rest of tractor .

Pull the oil pan and pressure lube the system. If you have a sever internal leak you can identify the source imediately.
Chuck

You should have used engine oil or lubri-plate
on the bearings. I would run straight 30 wt oil in the summer and see if that helps. Hal

Did you bleed the line going to the oil gauge?

Is the relief valve stuck open slightly?

I had this problem on an IH C200 engine and if I remember right it had to do something with a plug at the rear end of the camshaft. It was not in far enough and left a drain hole open causing the oil to drain back into the pan and not letting much pressure build up.

When rebuilding an engine very few people take the oil pump apart which is the heart of the engine. The bottom plate gets wore over the years and causes bypass of oil thus not generating much pressure. There is also a new gasket of a certian thickness that needs to be installed when the oil pump is reassembled.

There is an engine assembly grease that I use on the bearings when I put an engine back together. I also fill the gears of the oil pump full of grease so it primes quicker.

I would try another gauge first. Did you plastigage the bearings? If the crank had been ground and you now put std bearings in it, you will have low pressure.

Follow the advice from pete 23 first. The problem you describe is very typical of using the incorrect gasket. You must use the gasket that matches the filter base and not just the block.

If you have a pressure gauge that uses an oil line to the gauge, do not bleed the air out of it. Rather get the oil out of it. In cold weather conditions if the line has oil in it instead of air you may find you have a very slow reacting gauge, especially if you have 1/8 inch line.

Thanks for all the advice so far guys. Regarding the assembly lube, yes, all bearings, cam surfaces, etc we're coated by me with the engine assembly during assembly (I don't remember the brand name of it.)

Got up at 5:30 and moved the tractor back into the shop.

It was colder outside so oil pressure started at 30# at 1500rpm and then dropped to 20# at 1500 rpm after engine warmed for a couple of minutes. Dropped rpm's to low idle and pressure dropped to about 5#. That's a little different than I originally posted when I said there was no difference in oil pressure cold or hot. That was an incorrect statement on my part.

#1) I put a different oil pressure gauge on it and pressure read right at 20# so the gauge isn't bad (bummer.)

#2) Next I drained the oil and pulled the pan. Nothing plugging up the filter screen. Took bottom off of oil pump. There is almost ZERO gear wear on the base plate, the bottom of the gear itself is a little polished, and lower 1/2 of each gear tooth surface shows a little wear but nothing that makes me think this pump needs to be replaced.

#3) Next I pulled off the filter base, double checked to be sure I had the correct gasket installed, yep it matches the filter housing (vs. only matching the block).

#4) Next I pulled out the 3 check valves and inspected the conditions of the seats. The valves are fiber (vs. metal) and the seats aren't smooth like in a head. Sprayed everything with brake cleaner and swapped two of the valves around (not the one with hole in it) and then it was time for church.

Now I'm off to the children's piano recital so I'll start it up this pm to see if the valve removal replacement made a difference.

Next?? Thanks for all the ideas so far. I'll keep trying them.

Just thought of something else. I wonder if the filter base doesn't cover one of the oil gallery 1/8 inch pipe plugs also. If that plug was left out you would lose a lot of oil. Also, if you still have the fiber valve with a hole in it , get rid of it . That hole originally had a loose rivet in it, don't ask me why, but that is the filter bypass valve provided it is installed in the correct position and if not, that could also be a place for alot of oil to escape regulating valve. That should have been taken out 30 plus years ago, and then I would put in the steel valves and new pressure regulating spring. Make doubly sure the correct spring is installed in correct place.

I do recall 1 galley hole under the filter housing base but it was plugged. I'll get the steel valves and a new spring ordered this week. I have the Blue Ribbon manual for the c263 and the long/short springs were in the correct holes per the manual. Yes, it was the filter bypass valve that had a hole in it.

Thanks. I went out to bale with it tonight...and when it rains it pours. The rear gate on the baler started to hang shut...but that is a post for the implement forum. Thanks for the advice.

This is a simple test. Drop the pan, remove the oil pressure sender,connect pressure lube to fitting in block where you removed sender,force pressurized oil through fitting into block,and watch to see where the biggest stream of oil is coming from. If it is a really bad leak you won't even need a pressure lube. Before I had one I used air pressure and watched for the first spurt of oil before the air forced all the oil out of the system. A normal system will have drips coming from all bearings if the clearances are correct. Any area where a stream of oil is running out is a problem area. Set the oil pan under the engine to catch the drips. I made my own pressure lube system from a small spray tank.I removed the nozzle from the hand wand and threaded it right into the block,they were both 1/8 inch pipe threads. I then put about a gallon of engine oil in the tank and pressurized the tank. All you have to do then is squeze the hand valve on the wand and watch the oil drip down from the engine. It isn't any more work than spraying your lawn for dandylions. This is a fool proof method for locating the source of low oil pressure plus it lubricates the whole engine and you will have no dry start ups. Stop guessing where the problem is and do this test. This is like a CAT-Scan for engines
Chuck

Thanks Chuck. I was looking for a suggestion on how to force the oil in (and where.) I wouldn't have thought about forcing it into the galley hole. Now that you've got me thinking about that...could I fill a grease gun with oil and use that or would all the oil drain out the grease gun when I applied pressure...even if it held the tube end down?

You won't be able to get enough volume that way plus you need to be watching the leaks instead of pumping the grease gun.
Chuck

Just checked back on this topic, and I like Chuck's idea of using a hand sprayer, never though of that. We had a regular pressure oiler at the dealership at one time.

This is an old post but I have the same problem going on. John B you say that the frost plug on the rear of the cam needs to cover the oil hole? I changed this plug when I rebuilt the engine and I know I did not press the plug in far enough to cover the hole and I have low oil psi on fire up. Why is the hole there if it gets covered up I m kinda confused on this. Hope this post catches someone s eye and may be able to help thank you.