interchangeable piston rings

[Frenchy]

1957 A7 -- Are the piston rings interchangeable with anything else?  A Triumph 500, for example.  I have a cracked ring.

I know it's been a while since I've been on here, but my A7's almost done.  It runs and stops.  And (depending on your taste) it's starting to look good.  I'll post pics soon.

[MG]

Frenchy,
not all rings are interchangeable. First of all, the diameter and end gap have to be correct, and the play in the groove and the depth of the ring must be okay. The ring is matched to the piston/bore diameter, so that it is round when fitted in the bore and has the same amount of contact pressure all around.
Furthermore, some rings are tapered (single or double sided), others are rectangular.
Piston ring grooves can be machined to take thicker rings if the groove is worn out, but this better left to a specialist.

You can buy piston ring sets for the common pistons in the A7/A10, also for the old Hepolites. Maybe someone here has one left you could get if you let us know what pistons and what oversize you are running and which one broke.

Cheers, Markus

[BSA_54A10]

companies like Total Seal will sell you a single ring.
Post your old one to them with the size of the bore & they will send you a nice new one.
Usually only a day or two turn around

[Frenchy]

Thanks for the info.