Drilled through case! Watercooled

[itchyfeet]

I didn't realise that it wasn't possible to grind the excess plug off. Is there lack of access where the exhaust studs are positioned?

It's possible but going to be hard for the average person to cut it square and flat without doing more damage, remember people who need to do this because they didn't do it right the first attempt.

[Georgebug]

Thanks for all your suggestions.

I'm not sure what to do for the best.

I do have an undamaged head from a 1.9 with I could fit.

As all the studs/bolts are knackered on this side (but only one drilled through) would it be better to hellicoil the lot then do the extra repair on the one or replace the head?

I'm assuming head replacement is much more work

[itchyfeet]

Head replacement done properly involves removing pistons and liners to do lower seals, it is more work and you risk breaking head studs

Helicoiling the threads and adding an m10/m8 stepped stud with sealant is less work but may not last so could be more work in the long run.

It's your call.