Defender 300tdi vibration and noise

My defender 300tdi engine suddenly has a lot of vibration -the bonnet vibrates on idle. On cold start up there is a chuff / tick which sounds a bit like a helicopter rotor blade which increases with the revs but seems to stop when the engine warms up. It has just had a new head gasket so I know its not that. could it be an injector seal? Any ideas?

They rattle like a box of marbles as standard. Even worser at speed.

Hippo said:

They rattle like a box of marbles as standard. Even worser at speed.

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Mine ticks over like a sowing machine, on the over hand, my 200tdi is like a tractor.

Exhaust manifold sealed ok?
Tickover lower than it should be?

Tappets set right ? just done my 200 with similar symptoms, 2 exhaust valves were to tight although this had developed over some time.