Hi Andy,

>perhaps a catastrophic oil pump failure Trident oil pumps can give a lot of problems.

Don't know where you got that from because by-and-large it isn't correct, they don't - there is the odd original that had problems, but BSA made upwards of 30,000 of 'em, and there was a batch around for a while that someone hauled out of the scrap skip after Small Heath closed.

If the pump was a problem, any rod problem is more-likely the timing-side one, because of the crank drillings; otoh, the centre rod is between the two supplies to the crank through the centre main bearings ...

Centre rod letting go could simply be age - they're ally rods, ally rods have a finite life; even if that isn't shorted by lots of high rpm and/or knocking 'em against the crankcase mouth, an original rod would've been at least 54 years old ...

Hth.

Regards,