Diesel fuel in oil

[lectricman]

I just recently changed the oil in my Major for the first time since rebuilding the motor. I noticed that the oil was very thin and watery when I drained it. I could also smell a hint of diesel odor in it. I assumed that it was coming from the leak off rail on top of the injectors, so I replaced it with a new one from agriline. There were not any copper washers on it, and I'm not sure if there is supposed to be. I have also noticed that little to no fuel comes out of the return line while the engine is running. How much is supposed to be flowing? And finally, since changing the oil, the level on the dipstick has risen some. I think that it is still getting fuel in the oil, but I can't tell how. I have run the motor with the valve cover off and can't see any fuel leaking from around the tops of the injectors. It also sounds like it is knocking slightly at an idle now, after it gets warm. The oil pressure is only about 8 psi at an idle while hot. When cold it ranges from 20-40 psi, but never higher. I am running Rotella 40w oil in it. Any ideas or insights would be much appreciated. Thanks!

[Hesford]

Have you had the injectors out and overhauled If not it may be something as simple as a weak injector spring not springing closed hard enough after injection if they can be tightened up on a screw thread although if your not completely sure of what your doing with them I'd leave them for the injector specialist also the knocking noise could again be injector fault or injector pump fault hope this helps


Ash

[lectricman]

No, the injectors have not been overhauled to my knowledge, and neither has the injector pump. That leads me to another question. My injector pump does not have the small leak off pipe attached to it. There is just a bolt where it is supposed to be. How important is that pipe? Thanks.

[Brian]

Diesel in the oil on a Major is usually one of two things, leaking leak-off rail or leaking fuel lift pump diaphragm. You need to take the leak-off rail off and check the soldered joints to be certain it is not that leaking.

Having seen a couple of engine that ran on the diesel in the sump bypassing the pistons, I would not run that tractor until you have it sorted. When they take off on the diesel in the sump there is little chance of stopping them from putting a rod through the side or worse. Saw it happen with a Ford Industrial engine on a combine, driver needed new underwear very quickly, he tried to stall it by standing on the brakes in a high gear but she just slipped the drive belts until the BIG BANG!

The leak-off pipe on the pump is also important but is not going to give you diesel in the oil. It will fill the pump, possibly blow the seal into the governor, build up diesel in there and slow down the governor reaction.

[lectricman]

Thanks, Brian. The leak off rail is a brand new piece from agriline, but I did have to tweak it a little to make it fit properly. Still, I didn't notice any fuel leaking from it when I ran the motor with the valve cover removed. As I said before, there were no copper washers on the old one, is there supposed to be? Also the lift pump is new, but I will check it again. Can the sump be removed without splitting the tractor? I was thinking about checking all the rods again since it sounds like it is knocking.

[Brian]

There should be washers on the banjo bolts. Also check the brass fitting that screws into the head, have seen them split. You may also have a leak on the tube from the injectors to the outside but that would be a rare problem unless one of them has been loosened when you took the pipes off.

Would have thought you would have heard a misfire if the injectors themselves were faulty although you say you have a knock. I would not have expected a faulty injector to have got diesel into the sump without lots of smoke and/or a miss.

The sump will come down if you remove the track rod and axle support. We used to find it easier to take the whole front and side channels off as one unit and leave the engine suspended with heavy blocks under the clutch housing.

[lectricman]

There should be washers on the banjo bolts.

That's what I was afraid of. I haven't been able to source these washers anywhere. I have even checked all the local hardware and auto parts stores and no one has any the right size. I will be sure to double check all the fittings on the injectors, too. The tractor does have a very slight miss at idle, but it is barely noticable and I haven't seen any smoke. Thanks for all your help, Brian.

[Brian]

After checking up, it seems that washers on the leak off pipe are not essential, at least on the original pipes. Some people use them, others do not. The only ones shown in the parts book are ones on the external connection back to the tank.

[Dandy Dave]

There should be washers on the banjo bolts.

That's what I was afraid of. I haven't been able to source these washers anywhere. I have even checked all the local hardware and auto parts stores and no one has any the right size. I will be sure to double check all the fittings on the injectors, too. The tractor does have a very slight miss at idle, but it is barely noticable and I haven't seen any smoke. Thanks for all your help, Brian.

The washers you will need to get from an injection pump shop if you decide to use them. Dandy Dave!

[lectricman]

Hopefully the weather will cooperate this weekend so I can check it over really well again. The story of the one running away on the fuel in the oil has got me a little nervous about running it too much

[lectricman]

Had a little time to tinker with it today. I pulled the valve cover and checked everything over again. Three of the short tubes that go into the side of the injectors were slightly loose. I tightened them and ran the engine for a while. They didn't appear to be leaking best I can tell. Hopefully that solved that problem. Now, onto the knocking noise... When I rebuilt the engine I bought a set of used injectors off of ebay. They were in great condition and came from a running tractor. They weren't shipped with the short tubes to connect to the fuel supply lines, so I had to transfer them from the old injectors. However, I couldn't get one of them loose, so the #1 cyl still has the old injector on it. The tractor does have a slight misfire at idle and the knocking noise seems to be coming from the front of the engine. Plus, the misfire and knocking both go away when the engine is revved, so I am now thinking that the #1 injector is malfunctioning.

[EngineMan]

If you look at the fireing order, am sure it will be No 1 so refit a new injector or take it into the shop to have it done.

[AdrianNPMajor]

Hi Lectricman

The extremely low oil pressure worries me. Should be 40psi or slightly north of that. You've got Brian on the case, so you're in the best hands. Brian, would the diesel dilute the oil and explain the low oil pressure?

Best wishes

Adrian

[JonNWY]

Adrian

Diesel in oil decreases viscosity and reduces pressure. So yes.

How did this come out?