Bent distributor shaft?

[datzed]

Ok guys, I've had a previous issue in the mk1 (auto GLS) where the car was completely lacking in power and misfiring.
Took it to a mechanic who found it was a bend in the distributor shaft causing a VERY week spark (and sometimes no spark at all) to the No4 cylinder. Its been replaced.

My question is, what would cause a bend in the shaft? Reason I ask is, after getting it back from the mechanic, it was running fine, but Its gona back to its misfiring and spluttering ways after maybe 10 mins of driving and I suspect the same issue has occured again.

I've found a random internet picture and edited (below) to illustrate where the bend has been found (Its barely visible to the eye).

[datzed]

I should also mention the ignition system has been replaced (plugs, leads, coil, dizzy cap and rotor, points etc etc) and the issue has been confirmed to be the shaft.

[GRN_VAGN]

well the shaft is connected to the oil pump from what i remember,
could be something out of alignment there, thats the only part that connects to shaft, besides the IM shaft.

[Stan]

dud spark plugs can do wierd things as well, seem perfect one time and crap the next.

Also if your dizzy has points and a condenser - little metal can on a wire, inside, a dud condenser can do this as well - when they get hot making an otherwise intermittant or no fault become obvious.

as for the bent shaft, it has to be hit by something, be up against something, or not inserted properly to bend. possible an output drive issue at the engine end...or alignment issue, not going in straight.