hmm farther back than that...lots of motorbikes use them....shesh goes back donkeys years...and actually quite a great way of doing things when you get used to it, the advantage as I see it (I speak from much &^*&^^ about with Honda motorbikes ..) is that a shim is the thickness it is no more...no less and it doesnt move 1/8 turn as your trying to tighten it and change the adjustment (not that im bitter trying to adjust for a 1/1000" seperation..)

for the record later vw engines in the golf/polo went to hydrolic tappets which are nothing short of brilliant...NO ADJUSTMENT!

rant over....