L3130 engine knock/tick

[sawdustmaker]

I bought a 3130 recently and shortly after I started using it I started noticing a knock that seemed to get worse as the tractor warmed up. I Figured it was a rod bearing and pulled the oil pan and the rod caps and everything looked ok. I then pulled the engine out and put new pistons, wrist pins and bearings in it. I expected to find a spun main bearing. I did find some wear but nothing really bad.
I put it back together and fired it up and within a few minutes the noise came back. I did not pull the cam, but the lobes looked good and the tappets did as well. I'm fairly confused. I've never worked on a Kubota before and its obvious I'm missing something. Could the injection pump, the timing gears, injectors or oil pump cause a knock that's sometimes more of a tick?

 

[North Idaho Wolfman]

I bought a 3130 recently and shortly after I started using it I started noticing a knock that seemed to get worse as the tractor warmed up. I Figured it was a rod bearing and pulled the oil pan and the rod caps and everything looked ok. I then pulled the engine out and put new pistons, wrist pins and bearings in it. I expected to find a spun main bearing. I did find some wear but nothing really bad.
I put it back together and fired it up and within a few minutes the noise came back. I did not pull the cam, but the lobes looked good and the tappets did as well. I'm fairly confused. I've never worked on a Kubota before and its obvious I'm missing something. Could the injection pump, the timing gears, injectors or oil pump cause a knock that's sometimes more of a tick?

Asking us to evaluate a noise via text is just about impossible.
Make a video/audio of it doing it and post the video on youtube and give us a link to see/hear it.

 

[sawdustmaker]

This is before I put bearings in it. I will get a current video soon.

3130

youtube.com

 

[North Idaho Wolfman]

Did you put the thrust bearings in it?

 

[sawdustmaker]

Did you put the thrust bearings in it?

Yes I did

 

[North Idaho Wolfman]

It's super tinny like something in the muffler, like a broken baffle.
or possibly something with the clutch?

Does the sound change when you push in the clutch?

 

[North Idaho Wolfman]

I just remembered another that the shield on the propeller shaft was making that noise.

Another option is alternator or water pump, pull the belt and run it and see if the noise is still there.

 

[sawdustmaker]

I'm sure its in the engine. I'm uploading a video now from tonight.
Depressing the Clutch makes no difference. Also removing belt makes no difference.
It doesn't seem like something in the muffler. I put my hand on the muffler and it does not feel like its in there.

 

[sawdustmaker]

 

[sawdustmaker]

I loosened each injector line and none of them seemed to change the noise.

It sounds very much like a rod knock to me. It is very loud to the point it hurts my ears a little.

 

[North Idaho Wolfman]

ok those two videos sound nothing alike!

Yep you have serious issues, sounds like the pistons are slamming into the head!

 

[Runs With Scissors]

I agree with NIW, that sounds serious.

One trick I use to isolate noises, is to grab a long screwdriver or pry-bar and put the handle against my ear.

Then "carefully" touch the tip to different areas. You will be able to pick out what is making the sound pretty easy.

It's the same concept as a Dr's stethoscope.

(I used to have an actual automotive stethoscope, but it got smashed; thats when I learned about the "screwdriver trick")