diesel knock

[runningman]

Hi

havent posted for a while but need to pick your brains.

A while ago i posted a topic with regards to my fathers car, 1998, R reg Mercedes 300 td, 606 engine, 51000 genuine miles.

It developed a knock following very bad starting one morning. I have renewed everything regarding the fuel system but not the fuel pump. It still knocks at around 1250 rpm and dissapears when revs increased. Starts first time, no smoke runs well but seems to lack power and sounds rattley at high revs.

The only way i can stop the knocking is to advance the pump timing by rotating the pump 3 mm towards the engine. Engine runs great, starts first time, no smoke, plenty of power, sounds a lot smoother and better MPG. Took it for an MOT the other day and it showed near 0 emissions. Mechanic said engine sounds/runs great.

Trouble is, i still not convinced that its fixed.
Why did it suddenly start knocking, no warnings or symptoms of any kind.

Is it possible that the counter weights on the timing mechanism WHICH IS LOCATED ON THE BACK OF THE PUMP DRIVE SPROCKET are jammed. Thus causing the pump timing to be out of balance.

It needs to fixed properly it in case irrepairable damage is done to the engine.

Regards