In what way did the valve gear become 'loose and rattly'? If you mean you
suddenly had large clearances in the rockers, and the pushrods cam and
followers are OK, then either the adjuster threads stripped or the rocker
shaft bolts did. That would certainly account for noise and loss of power,
not so sure about blue smoke though.
----- Original Message -----
> Does any one have any ideas why the engine developed a loud knocking and
> blew' the cloud of blue smoke, the valve gear became loose and rattley,
> it lost power and yet nothing seems to have failed.