Prime the oil pump?

[Rabidd-HT]

I just picked up my head and block from the machine shop and will begin the reassembly of the motor on my YM135 today and my question is can the oil pump be primed? This is my first diesel rebuild and I want to be sure it is pumping oil. There are two phillips screws (one on top and one on bottom) that appear to be plugs. Any help would be greatly appreciated.

 

[Norm-HT]

Engines is engines. Just fill the filter and crank with comp. release engaged until you show oil pressure.

 

[Rabidd-HT]

Well I cranked and I cranked then I cranked some more but no oil. Turns out there is a bleeder on the back of the head so I removed that with no luck so then I joined a few different size hoses together so one end would fit inside the bleeder hole and the other on a small funnel. I then filled the funnel and let that drain awhile put the plug back and presto! I had oil pumping out the rocker arms.
I was very happy to hear this thing start after the injector pump failed to pump fuel as well. I guess it sat too long and had froze up. After a good soaking with wd-40 I was able to get the accelerator (for lack of knowing what it is really called) un-stuck and got it pumping fuel. She runs!

 

[winston-HT]

Congratulations!

 

[Rabidd-HT]

If the oil filter valve failed would that cause the oil system to lose its prime?
After the initial startup I had oil pumping after priming the system. After letting it set a week I started it up and had no oil pressure, primed it again and had good oil pressure.

 

[winston-HT]

I doubt it is the relief valve. I would suspect a weak oil pump. Do you have a gauge installed? The pump picks straight up through an oil pipe and through a passage in the block. It is possible the gasket sealing the pump to the block is leaking but there should be an oil leak if that were so. I would suggest testing with a gauge if you haven't already.

Notice the suction and pressure outlets on the pump. Gasket leaking there could be possible but I don't think likely. The suction side goes right through the block and down to the suction pipe that should be submerged in oil. Seems logical to me a good pump should continue to prime after initial priming.
http://www.hoyetractor.com/PROD/OP-4060.htm

 

[Rabidd-HT]

Looks like I will be splitting the tractor again. I let it set a few hours went out and started it with the valve cover off again and no oil at the rockers.

 

[winston-HT]

Have you or do you think it might be worth it to check oil pressure? Sounds like you have had it split, did you notice the oil pump at that time? Any oil around where the gasket seals it?

 

[Rabidd-HT]

Yes, I rebuilt the engine, all new bearings, bushings, rings, valve guides, valves, seals. So when I had it apart I inspected the pump to make sure it was clean, looked for visual signs of wear. Did not take a gauge to it. Installed a new gasket because before the rebuild I had a lot of oil dripping out of the drain hole in the bell housing so I wasn't sure if it was the rear main or the oil pump.
I have not checked actual oil pressure because I have no way of doing so but when it does pump I have oil running at a very good rate out of the rockers at idle and it will at times shoot it over the top of the valves.
When I read your post about the oil pump I couldn't help but think that the oil had to pass through the oil filter and check valve before going into the oil journals. Keeping that in mind I would think that if there were a problem with that check ball it could effect flow and of coarse pressure.
Keep in mind at this point I am willing to entertain any idea other than the oil pump, that thing isn't cheap and its a lot of labor to replace.
I think I will take that valve out today and at least have a look at it. I already have way more in this tractor than its worth.

 

[winston-HT]

Don't blame you checking easier things first. Just my opinion that any good gear pump should be able to pick up prime in a designed system unless there is something amuck between the oil supply and the pump. In this case everything else is on the output side of the pump including the filter and relief valve. Don't know that a pressure check is going to help you but you could test with something like this. http://www.hoyetractor.com/PROD/OPT-060.htm

Oil dripping out of the clutch housing drain hole does sound a little suspicious.

 

[Rabidd-HT]

nothing dripping out of the bell housing now, that was before the rebuild. I forgot that I also put a new O ring (which is just a seal) in that oil pump along with the new gasket. I took the oil valve out and everything looked good. There was no corrosion or obstruction on the ball, seat or spring. I went ahead and pulled the decompressor and cranked it with the oil filter off and nothing came out of the oil journal that it is supposed to. When I re-assembled the motor I did use a Teflon sealant on the oil pickup. Must be a bad oil pump.

 

[Rabidd-HT]

Not to revive an old thread but one of my peeves with forums is when they leave them without posting the solution. So yes it was the oil pump. I was able to use a feeler gauge around the outside and it was close to max tolerance. I was not able to gauge the (teeth) of the pump as I had nothing that small. The tolerances on this pump are so slight that it does not appear that even a thin piece of paper can fit between them. So do not trust just looking at them. It definitely fooled me.

 

[winston-HT]

Congratulations again. <E>:mrgreen:</E>