G'day Weedgrower and welcome to the ODK forum.
This mower is a 1979 Vulcan Gold 4 mower with a Briggs and Stratton 4 Hp motor ,just a rebranded
SupaSwift mower.
https://www.outdoorking-forum.com.au/forum/ubbthreads.php/topics/54245/5.htmlYou could dismantle the engine and try and buy new piston rings from a mower shop or online ,rings are around
$30 new or just buy another mower with a briggs and stratton motor then swap the motor over ,it's not
difficult to find a mower under $50. The motor from a Rover or Masport mower should have the
correct crankshaft length.
I haven't put rings in one of these Briggs for over 20 years as I can buy a good mower at a tip shop for $15.
Anything can be rebuilt though ,it's just a matter of cost.
Cheers
Max.