Farm Pro 2425 Engine Knock

[NoCashValue]

Alright, back for some more help.

Got the engine back together after tearing it down. It has new bearings, pistons, liners, rings, gaskets.... the works.

Got it together and started today. Took a long time to get it to start, but it started and I moved it out of the garage. It is still smoking (white smoke) pretty good all the time. I dont know if they smoke is a problem, but I imaging it shouldn't be smoking much at idle, and when you throttle it up it does bellow out more smoke (brownish white). After letting it idle for a while, I brought up the RPMs for a little while (15 sec?) and when I let off it started knocking really bad. Knocking sounds exactly like what caused me to start down this path. At the same time as the knocking started, the valve cover started smoking from the hold down nut holes. It was also smoking white smoke out of the breather on the bottom of the tractor. When I shut it down I pulled the oil fill cover and noticed a lot of lingering white smoke. I put my finger in the hole for a few seconds and it comes out wet (drips of water/condensation?). This seems wrong to me as well. **** it...

I'm at a loss again? Could this be a cracked head? Hopefully not a cracked block. I attached some images of the rebuild with all new parts, and also an image of the white smoke at idle.

Maybe you guys could point me in a direction on what would cause the white smoke in the crankcase?

 

[piper184]

your work looks clean and careful. As for the white smoke, I would expect a rebuilt engine to smoke a little until it is broke in again.
The real question is if you are getting coolant into the combustion chamber or the oil pan. I think there are test kits available to do some sample testing of the oil and coolant to see if they are mixing.
The knock is perplexing to say the least. I don't think a coolant leak would contribute to a knock unless it was a massive leak.
Sorry I don't have more to offer than suggest magna-flux of the head to check for cracks. Although at this point I don't really think that would lead to the knocking condition.
Hopefully someone with more experience will chime in.

 

[Agvg]

Are it running on al cylinders? Are all exhaust ports warm? Did you check the injectors?

 

[Bob Rooks]

White smoke that lingers in the air is unburned fuel. White smoke that dissipates rather quickly is moisture, and can be caused by just cold exhaust (goes away after a short time) or coolant in the combustion gasses. This is all dependent on ambient temperature and humidity conditions too. In your case I suspect a dribbling injector. Next time you hear knocking, loosen the fuel line nuts at the injectors one at a time and notice if the knocking sound subsides or goes away. The brownish exhaust under acceleration suggests over-fueling, either from timing (unlikely here), or clogged air filter. Worth a check.
I'll second Piper184's assessment of your work - nice clean job.

 

[NoCashValue]

Thanks for the pointers guys! This actually may have found something.

I tried running the tractor and loosening the injectors. Injectors 1 and 3 caused the engine to bog down pretty good, but loosening injector 2 didn't seem to have any effect on the engine. I also noticed when I loosened 1 and 3, the stream of fuel seemed to pulse out as a stream, whereas on injector 2 the fuel seemed to "foam" out. See the picture below - not sure if it is obvious but there are white foam bubble on the fuel line just behind the nut. Don't mind the water droplets everywhere else, it is starting to rain at the moment. Also wanted to note that the smoke from the exhaust did not go away as I loosened the injectors.




I have some spare injectors I could swap in. The current injectors are all new that I bought when I started diagnosing the issue. So I can try swapping one of the old ones in, or swapping this injector to another cylinder and see if the problem follows it.

Also wanted to note that while I just ran outside and started it to test the injectors, it was not knocking at all (it seems it has to get warm before it starts knocking. But there is a "ticking" noise. That ticking does disappear when I loosen the #2 injector.

Does this sound like I just have an injector issue?

Thanks again! Really appreciate the help.

Eric

 

[Bob Rooks]

The foaming from #2 injector suggests compression blow-back because the pintle valve in the injector isn't seating (also why it would be dribbling ((and ticking)) fuel when it shouldn't). Hopefully the knocking is the accumulation of fuel in the combustion chamber trying to hydraulic lock (this is as serious as a bad rod bearing). Change out that #2 injector and see what you have.

 

[NoCashValue]

Alright, had some time this morning to look into the tractor again. I pulled the #2 injector and swapped it with another one. No effect at all.

I decided to remove the service cover on the fuel pump to try and see if anything was sticking or causing the injector to receive less fuel than the other injectors? I can't say that anything was gummed up, but I did clean everything out with carb cleaner and WD40. Rinsed with new oil and started it back up. The number 2 injector now causes the motor to stumble when I loosen the fuel line. But now the engine is knocking really hard again. This knock was not occurring since the last post I made. and seems to be a new issue?

I tried cracking each injector to see if one seemed to be the cause of the issue, and now #3 makes the knocking sound completely go away. I recorded some videos of this effect as a reference.

FarmPro 2425 Engine Knock 4

I assume now that the knocking sound is a "fuel knock" based on the ability to remove it by cutting fuel to an injector.

I also noticed that if I increase the RPM the knock continues while the engine is under load, but as soon as you let off the throttle the knock sounds goes away until the engine speed has stabilized. Just a reference point, trying to gather some diagnostic data.

Is there a possibility the fuel injection pump is the problem? Could the injectors be out of sync?

Thanks again as always,

Eric

 

[piper184]

Just some random thoughts here:
If you swap the #1 injector with the #3 injector and the problem follows the injector that will be easy to fix. If the problem stays with #3 then it is either the pump or a problem in that cylinder.
I can see how excess fuel could cause more combustion in one chamber, but if it goes too rich it wont fire. I would think that the smoking might be related somehow. If you are getting enough fuel overload to cause hydraulic lock it would definitely be washing down the cylinder wall and that would be really bad and should be obvious if you pull the head.
Finally could there be a restriction in the intake manifold that would cause the #3 cylinder to run richer than the others? For that matter could the valve timing and clearance be off for #3? Maybe something slipped when you put it back together. A second look might be a good idea.
One question I have is could that piston have been installed wrong? I don't know if they have to be installed a certain direction.
If #3 is knocking when firing but not when coasting what physical parts could do that? Rod and crank bearings, piston and wrist pin. Could the piston be slapping the cylinder some how?

 

[NoCashValue]

Hey Piper,

All good points, I have tried moving the problem injector around and it seems like the problem does not follow the injector. I believe the reason the knock has changed locations is due to my meddling with the injector pump fuel rack.

A little more backstory - back to where this all started in post #1. I bought this tractor "running" but with significant issues. In the original diagnostic we determined there was an issue with the fuel delivery being inconsistent, and when I pulled with injector pump timing gear I found the woodruff key on the old pump was sheered off and the bearing on the shaft worn out. I bought a "new" pump and pulled the old one. I still have the old one and have been going through it to learn a little more about how the pumps work and how to tune them.

So fast forward to the new pump. Arrives with all the ports covered, looks new. Try to pull the fuel shutoff and it is locked tight. Before I install it on the tractor, I pull the service cover to see if the fuel rack is stuck and it is. Golden gummy film on the entire gallery. I sprayed some WD40 in the whole compartment and used a screwdriver to pry the rack back and forth to free it up. As a reference, I have my old pump available and for comparison, it's fuel rack is smooth as silk. In the process of doing this the screw down clamps on the rod slip in position. See the image below for a reference of the screws I am talking about - this in on my old pump that I have laying around now.



I realized that this was probably an issue, and loosend all of the clamps. Slid them all to the left side of the rack until each "bound" and then re tightened. In retrospect, I think this was the point where I messed up.

Cleaning the gallery again today also caused one of the clamps to slip - so I moved it and re-tightened. After restarting the tractor is has the loud knock on the #3 cylinder. Typing this all out makes me believe I have messed up the injection pump calibration/setting and that is the source of my issue.

Can anyone confirm this is my issue? And if so, is this something I can correct or do I need to replace the pump again or have this one serviced?

 

[thepumpguysc]

Moving the segments IS DEF. where u messed up.!!
THOSE ARE the individual fuel adjustments for each cylinder..
I have set them ON the tractor before..{Ford}
IDK if "YOU" should do it while the pump while its running..??
Here what I suggest>> remove the side cover, pull the stop to find out which DIRECTION is STOP..
Then, with the engine NOT RUNNING, move # 3 segment SLIGHTLY to the stop direction..
U have HEAVY BLACK smoke, right ?? that means its over fueling.. so u wanna cut the fuel back.. so u move it in the cut-off direction..
AND TIGHTEN..
THAT adjustment is very sensitive.. so go slow.. restart the engine & see what u have done..
Good luck..