A65 Rocket coils

[Cmcl.1959]

Hi and seasons greetings to all at BSAOC.
This is a query regarding coils for my 1965 Rocket. Whilst tinkering and preparing for the Winter lay up I got a mild shock from the casing of the coil to cylinder 1.
I've read on other forums that this may be due to the coil having been crushed by over tightening of the p-clamp causing the inner windings to touch the outer case. I intend to replace both coils which are I believe MA6 type and 48mm diameter.
As upgrades to the bike, I fitted Pazon sure fire electronic ignition. On their website it recommends two 6v Lucas M6 coils (part no 47275) which are 40mm diameter. I already have two new ones of these from my previous bike.
My question is can I shim out the coils by using a strip of rubber to fit the clamp. Or will this cause overheating?
Thanks in advance for any help
Clarke

[rhyatt]

I'm pretty sure yes,
Some bikes had the coils mounted in rubber grommets.

Yes , the ht spark goes from the coil centre terminal to earth , but the earth is via the negative side of the coil , not the coil casing.

This is why ignition has condensers to absorb the back emf.

[Allan G]

Shimming out the coils with strips of rubber is often advised by some makers of electronic ignition to help prevent damage to the EI. SO yes. Do it.

[Cmcl.1959]

Thanks for the help guys.

Regards
Clarke