Don't understand this at all. Rings are free floating in the grooves. What stops them spinning is because they press on the peg. Sooner or later, they are going to want to put pressure on the peg.J1MS wrote:Pencil marks in line with ring pegs helps align the piston rings on assembly.
If piston rings are accidentally pushed against the pegs on assembly the pegs can be loosened even if the piston dosnt fully slide into the barrel.
They are an interferance fit so any undue pressure can efffect their later performance.
Sounds like the problem is ring pegs aren't being set in the pistons hard enough. Put a small curl in the tail of the ring peg that bites into the ali. on the inside. Or something. Can't be that hard to work out a solution surely.
Jagged teeth on the ring peg pehaps?
Form another thread posted by another member:
Now finally, the most perplexing cause of failure. Ring pegs. On the face of it, if a ring peg moves either in or out, it would be natural to assume that is has not been a tight enough fit. Whilst we have seen batches of pistons where the peg could be pushed in with a finger nail, we have also seen peg failures where the peg has simply been worn away by the piston ring or “worried†until it has loosened. Under these circumstances, we need to look elsewhere for the cause of the ring peg failure. Obviously the peg is being loosened by the sideways forces exerted by the piston ring. These are brought about primarily by the ring moving in and out of the exhaust port (and to a lesser extent the transfer ports) causing it to change shape. If the ports have been enlarged, this will put extra load on the ring peg and may cause failure. If the peg is in the centre of the piston, the loads on the peg will be balanced and less likely to dislodge it.
I see said the blind man.
So, it would appear it's the fault of the exhaust port. Hmm, what to do.