Hi, haven't posted for a few years now, which means my M20 has been running fine. However, I am trying to fit new rings on BSA A10 and using new "Hepolite" rings. I have ring compressors and can get the barrel to slide over the top and middle ring. However, the two piece expander ring seems too big. 100% sure the spring ring is seated in the grove of the outside oil ring, but just can't get the ring to compress enough to get the barrel down over the last ring. Your knowledge and help greatly received. Regards Pat.
Ps I haven't been inside, just been extremely busy!
Re: Off topic - Heppolite two piece expander/oil ring
I don't know which rings are fitted to the Hepolite A10 pistons...They were using Hastings rings from the U.S. but I'm unsure if that is still the case...How long have you had the pistons?...
One thing I have noted with American piston (oil) rings is that they run a much higher ring pressure than we do in the UK... The first JE Pistons I had made in the States used there own 'Total Seal' rings and were a nightmare to fit as they were so 'tight' when compressed...They were three piece and I used to tweak the ends of the central rail to reduce the spring pressure a bit..American 'Cord' piston rings which were popular a number of years back were the same......Current JE Pistons still use a 3 piece scraper but they've changed to Japanese rings and they are a 'normal' fit compared to British rings I'm used to... Ian
Re: Off topic - Heppolite two piece expander/oil ring
I've had the pistons for many, many years, at least 40 years. The rings were indeed a bugger to fit. They are in now, but they did seem much tighter to fit than a one piece scraper. The job would be impossible without ring compressors.
Re: Off topic - Heppolite two piece expander/oil ring
Yes Ian, some brands of USA made rings are very difficult to fit due to the spring pressure. Years ago I fitted Grant rings to a Velocette and the three piece oil control ring made the piston feel like it had seized in the bore. Even with the proper ring gap it did not feel correct and starting the bike was not easy. I was told this was normal by the manufacturer and after about 100 miles or riding it ran better and the bike burns no oil at all.
