Well I did listen to the advice and just take up slack in the Jesis bolt (100-325A), not tighten hard at all, in fact I have had the E7 for over 2 years still going strong and no problems with Jesus bolts etc.
Had a lucky escape today, landed to tweak the engine, spooled up and the heli did a Pyro on the ground!
Cut to investigate and when picking up the heli felt play on the main shaft, missing Jesus bolt, found next to the heli less the broken off nut part, must have broken then fallen out when I spooled down, no other damage.
When I tried to remove the shaft it was siezed to the OWB sleeve, ended up having to dimantle all the bearing blocks, servos out the lot to remove the shaft and gear etc, PITA, 3 hours work to get it back to the point where I could sort out the initial problem.
Managed to free the sleeve with a little applied violence with hammers and blocks of wood etc, the shaft had a groove where the top part of the sleeve had cut into the main shaft a little.
Cleaned up the sleeve bore with emery paper so that it slides onto the main shaft again and have a spare shaft so OK there.
Main problem is getting hold a spare Jesus Bolt, no one is stocking them in UK after all this time, outrageous.
Found another M3 shouldered bolt from Mikado, longer but I cut to length, the shoulder was about 1mm too long so that the nut would not take up all the slack so filed 2 M3 washers to fit into the square slot of the tail gear assy and, now the shouldered part is just right taking all the torque forces, the threaded part is not under any stress.
My question therfore: does the "special" notation refer to the bespoke shoulder length? Or is there any special heat treatment used to make the bolt more reilient?