Hello all,
I know this subject has been discussed here before, but I'm having to repair a broken sump plate stud on my 39 WM20 having the badly drilled out stud hole alloy welded up and re tapped, The thing is i thought the threads were 1/4 whitworth so I tried my tap in a set of scrap cases it removed a lot of material and my spare stud now wobbles about although it does tighten up it did the same when I tried it on the timing cover screw holes! So could the threads be 1/4 CEI or maybe 3/16 whitworth? any info would be very helpful and much appreciated,
