Farm Pro 2425 Engine Knock

[NoCashValue]

A little update. I have been tied up the last few weeks and not able to work on the tractor until this weekend.

I don't know if it was mentioned in my earlier posts, but all 3 injectors were replaced with new injectors when the head gasket was replaced, along with new glow plugs.

I rechecked the timing and believe it was set correctly. Started the tractor to move some dirt and rocks and it starts knocking really hard after a few minutes of working. It will come on all of a sudden and the tractor will slowly shut down without smoke or any other indicators. Temperature is heating up beyond the 60C once it was working. I'd say it was right around 100C when each time it shuts down. I can restart it immediately and the knocking seems to be gone, but comes back after a few minutes or once I start to load up the tractor. It does seem to start pushing a lot of smoke out of the crankcase breather as it begins to die.

I did go and purchase a diesel compression tester and found all of the cylinders easily build up to 375psi in about 3 cycles. All reach similar pressures and do not seem unbalanced. I did find that when I pulled out the 3 brand new glow plugs, 2 of the 3 tips seemed to be "melted" off. They have a hole in 1 side of the tip, and the other side is what looks to be "melted" open. I haveused the glow plugs a few times to start the tractor but otherwise they are unused. I found this interesting, maybe they were wired to be on all the time? I replaced them with my old glow plugs for the time being.

Also noticed it looks like the engine oil is filling with diesel fuel. I thought the oil looked diluted so I have changed the oil. Within about 15 minutes of use the new oil looks to be diluted and "watery" as well. I could not determine if this was diesel fuel, hydraulic oil or coolant, however I believe it is diesel fuel since the hydraulic reservoir is staying at the max fill level and the oil is not turning brown or milky.

It did seam like if the engine began to knock that I could press the primer on the fuel pump and it would be soft. Pumping using the hand primer seemed to make the knocking go away sometimes but was not always conclusive. I pulled the fuel line from the tank to the pump and verified it was not constricted. Pulled off the sediment bowl to look for restrictions and did not see anything alarming other than torn filter screens. I did end up placing a new sediment bowl on from tractor supply when I reassembled.

I'm at a loss again. I pulled the valve cover to verify there are no sticking valves while it is running. Can't come up with a good reason for why there is fuel in the oil while there is still good compression, or why this knocking is still happening.

Looking for any more advise for things to check after.

Thanks again - Eric

 

[Agvg]

Do you have any fuel driven preheater in the intake manifold? If not have you tried to loosen one injector line at the time to see if all cylinders react in the same way? Except the preheater tis not many ways for diesel to enter the engine, dead cylinder, leaking injection pump or feeding pump.

 

[thepumpguysc]

The knocking almost sounds like AIR in the fuel system.??
U say once it starts to knock, it slowly dies out..
& u said, working the HP will make the sound dissipate..
It sure sounds like air to me..
Pressurizing the fuel tank w/ air, about 4 psi, will usually show a loose fitting or pin hole pretty fast..
U could lightly dust the fittings w/ baby powder & any leak will show itself..
Good luck..

 

[thepumpguysc]

BTW> if u google>> "Farm Pro 2425 injectION pump"
Theres MANY threads about this mdl machine..

 

[NoCashValue]

Hey thepumpguysc, I completely agree it sounds like air in the injection lines. I'll make another attempt to check all the connections for air. I have parked the tractor for the time being.

Any reason why the engine oil sump would be filling with diesel fuel? I was starting to think the injectors may be dripping or something else? I did replace all 3 injectors when I started into trying to fix this issue.

I am also beginning to suspect the injection pump as well. The pump was purchased as "new" open box from a seller on ebay. When I received it the condition looked new, but the fuel rack was stuck, as well as one of the injector/plunger springs behind the rack. I ended up freeing the rack and the plunger before getting the tractor to run, but now I am second guessing the quality of the injection pump.

IF the pump was not operating correctly could this potential cause the injectors to overfuel? If the plunger sticks in the "up" position would that keep the fuel pressure in the injection lines high enough to drip/leak fuel into the cylinder?

I am convinced there is fuel leaking into the oil sump to fill over time and becoming diluted with diesel. I have changed the oil 2 times since the first time I noticed this and have found the oil over filled and diluted each time. In both cases the tractor had been run for no longer than an hour.

Thanks,

Eric

 

[thepumpguysc]

I would suspect the lift pump, if it has 1..
THAT would account for ALL your problems..
A leaking Lp would flow a large amount of fuel in the cc AND..
...with it leaking, wouldn't supply the correct amount of fuel to the inj. pump..{air}

 

[piper184]

I had that thought too but on my Y385 the lift pump attached to the injection pump and when it leaked it filled the IP case with diesel to the point it overflowed the breather. Unless the lift pump is connected to the engine block, I don't see how it could put diesel into the oil in the engine crankcase unless the seal between the IP and engine at the drive end was also bad.
If the leaking injector has indeed damaged the cylinder wall as bad as it looks, that is the most likely place for diesel to get into the crankcase but that would mean that the injector is still leaking excess fuel.
On my tractor the lift pump was run by a push rod powered by a cam in the IP. That rod was sealed by an o-ring and it proved difficult to keep a working seal. I removed the lift pump, made a cover plate and gasket to seal off the r hole in the IP. I then mounted an electric lift pump near the fuel tank and all has been well since.

 

[NoCashValue]

Just wanted to update everyone on the tractor. I ended up ordering a rebuild kit and started to tear it down today. Found that 2 of 3 of the pistons were damaged and cracked near the piston rings. All of the piston rings are intact and look to be in acceptable condition. See the attached pictures for reference.



Originally I had suspected a spun bearing, but all of the crank bearings look to be in excellent condition.

Just wanted to update the thread in case anyone else found a similar issue and wanted closure.

Thanks,

Eric

 

[thepumpguysc]

How was your ETHER usage.?? Were u the only one operating the machine.??
I ask because someone else might have used it..??

 

[Bob Rooks]

I suspect excessive ether (starting fluid) usage too. The flame front is passing by the first and second ring. Also, the ring indexing could have been bad. I couldn't quite see the liners well enough to detect if they are scored or not, or how big the ridge is. At any rate, the liner condition will predicate if you can reuse them, and the rings.