New Major clucking sound at certain revs

[andymann]

Hi all,
I have a 1957 Fordson New Major. It had its head reconditioned a year or two back, but unfortunately I haven't gotten around to doing much work on it since. At certain revs, a medium-sound sort of knocking/clucking can be heard from the engine on the side of the diesel pump, towards the front of the tractor. At higher revs the sound goes away and runs perfect. The exhaust fumes are normal coloured. Any ideas as to what this could be? I was thinking along the lines of a bad camshaft bearing, but I'm a novice with this stuff. Thanks in advance for any replies, they are greatly appreciated.

[oehrick]

The injection pump coupling element might be worth checking Andy, wear backlash or a fracture can give a chattery sound which tends to reduce as speed increases.

Happy hunting