Knock in a 1210

[Stimie]

I've owned my 1210 tractor for several years and have not had any real issues. However last year I pulled the injectors to have them rebuilt (no issue but the tractor has about 1600 hours and I figured just a maintenance repair). Installed the rebuilt injectors, got the tractor running and within a couple minutes I got a knock coming from the topend of the engine. The number two cylinder is where the knock is coming from. I can crack the fuel line feeding that injector and the knock goes away.
I'm thinking it might be a wrist pin. The parts break down shows a bushing in the rod end. But I fired the tractor to move it in the shop and the knock was not there. The tractor ran about 5 minutes and the knock came back. Has anyone had this kind of issues before or got any ideas?

 

[Stimie]

One other thing I forgot to mention the tractor's got a real bad gray/white smoke. never really had any smoking issues.

 

[kirkawilson]

Engine knock results from the miss-timing of the combustion process between the injector firing and piston movement, resulting in a knocking sound from the engine. You might run some diesel purge through your engine. The lubricant in the purge will reduce the “nailing” or hammering in the injectors and the clean fuel will reduce the combustion knocking sound.