Got a 48000 mile 74 Stag in for a major service, very noisy timing chains and top end....
So do the engine part of the service, and as the timing chains were utterly shagged, fit a set of German chains with new guides and sprockets, then check the tappets - no 2 exhaust at 38thou, and no 6 exhaust at 34thou but all others within spec...... not good but just a couple of relatively quick adjustments.
Whizz out the LH cam, and slip out the buckets, to find the offending shims punished to hell with a big dent where the stem was, and spread out like plasticine on the other face, so with the assumption of dodgy hardening on the shims, mic them up and fit new ones to suit...
All good you think? Well it was until I decided to check the other shims for similar damage.... wished I hadn't but good for the owner I did.....
Two valve springs broken and preventing the refitting of the followers as they are sticking out, and 6 of the 8 guides on that head so loose I can get 2-3mm side play on the stem just by pushing with my fingers....
Now that head has to come off, and probably the right hand one too as so far as I can tell from the history, there has been little engine work done and I'm told it still has original leaded exhaust valves, so I'm not going to run a sweepstake on these heads coming off easily....
Moral - if you have noisy valve gear, even a tappet, for Christ's sake don't ignore it - this engine was in serious risk of dropping a valve, probably before it dumped it's chains....at least head work is cheaper than a full rebuild!
Russ
So do the engine part of the service, and as the timing chains were utterly shagged, fit a set of German chains with new guides and sprockets, then check the tappets - no 2 exhaust at 38thou, and no 6 exhaust at 34thou but all others within spec...... not good but just a couple of relatively quick adjustments.
Whizz out the LH cam, and slip out the buckets, to find the offending shims punished to hell with a big dent where the stem was, and spread out like plasticine on the other face, so with the assumption of dodgy hardening on the shims, mic them up and fit new ones to suit...
All good you think? Well it was until I decided to check the other shims for similar damage.... wished I hadn't but good for the owner I did.....
Two valve springs broken and preventing the refitting of the followers as they are sticking out, and 6 of the 8 guides on that head so loose I can get 2-3mm side play on the stem just by pushing with my fingers....
Now that head has to come off, and probably the right hand one too as so far as I can tell from the history, there has been little engine work done and I'm told it still has original leaded exhaust valves, so I'm not going to run a sweepstake on these heads coming off easily....
Moral - if you have noisy valve gear, even a tappet, for Christ's sake don't ignore it - this engine was in serious risk of dropping a valve, probably before it dumped it's chains....at least head work is cheaper than a full rebuild!
Russ
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