1650 Knocking sound

UncleD

Member
I just bought a 1650 diesel, early model, at an auction.

Tractor runs good, but has a knocking sound at the rear of the engine at medium RPM. Slow it down, the knock sound almost disapears, speed it up (around 1800 rpm) and it goes away. Oil pressure is about 38-40 psi. Almost sounds like it's coming from the Hydra drive.

Opinions? Thoughts? Could it be the hydra drive? Or do I have an engine issue?

Thanks for any input :)
 
Three questions: If you hold the clutch petal down will the noise go away? If it does that would indicate at least to look at the Hydra-power. Are the rear engine mount bolts tight? Also the bolts that attach the bell housing? Third can you short out the cylinder and make the noise go away.
 

I will try pushing the clutch in tonight to see if that makes a difference. I should have thought of that one myself lol. And check the bolts. What do you mean by "shorting out the cylinder"?
 
Loosening the injector line - a bit messy and potentially dangerous if you are not careful. Diesel fuel at high pressure can penetrate the skin.
 
loosen at injector it will seal up again better there than the washer seals at the pump may not reseal as easy or need replacent after being loosened.
 

Seems there are a couple issues at least. I checked the motor mounts and the bell housing bolts, all are tight. Ended up tying the clutch down and that stopped most of the noise, but I still had a slight knock in the engine. Started shorting out the cylinders, each one would change the sound, but the 5th cylinder would stop the knock in the engine. It's not a loud knock, but it is noticeable if you sit and listen. But goes away about 1200 rpm and above.

Most of the knocking noise is either in the hydra or possibly the chain coupling as LP mentioned.
 
I had a knock in my 1650. Good oil pressure. Knocked loudest under a ard pull. Dealer came out and hung under he tractor while stuck the field cultivator in deep and she started knocking loud. Checked it with a stethoscope and said it was not a rod. He said run it. About five years later it had staeted making the knocking sound all the time under a pull and while looking around I see some smoke come out around the exhaust. Found a small hole in the exhaust manifold. Put a new exhaust manifold on and it solved the knock problem. Never ever sounded like an exhaust leak.
 

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