just done some calculations for the ring end gaps on my wossner pistons. from there website they say .006"x bore for top/middle rings .
so my bore is 86mm (3.385") .006 x 3.385=0.02031 . converted to mm's= 0.515mm. so top/middle ring gap is 0.51mm . if anyones willing to check my working out and if this sounds right for a zetec turbo it will be much appreciated