Hi Tom,
Thanks for your concerns and questions. I've looked back through my photos and there is no grove machined in the block to accommodate any form of retaining clip. I'm assuming the factory plug was held in position simply by the friction of the tolerance fit. The amount of plug you can see protruding from the back of the block was left there by me, I measured and belt sanded the brass plug so when tapped in flush would leave clearance on the cam shaft, when I was tapping it in it was quite a snug fit. I left it that little extra proud for two reasons, I didn't want to give it that one extra tap that sent it home onto the cam shaft, and I knew it was tight and additionally clear of the cam shaft so left it where you see the photo. I understand you are a Nailhead guy and someone else may be able to help here, what kind of crankcase pressure would be expected? I will be running the factory vents and PCV valve back to air intake and rear of the carby. I didn't expect the plug to be exposed to excessive pressure. I'm more than happy for any comments here as I don't want to be caught on the side of the road with a catastrophic oil leak from the plug. I'm starting to think it might be safe to fit a steel plug when postage recommences.
Regards
Marcus
