MAMOD PISTON CYLINDER ASSEMBLY TE1A SR1A SW1A SA1 MM2 SP2 SP3 MEC1

This is the Mamod Standard Piston and Cylinder

These things do wear out when you've given your engine a bashing or the wear of the passing years takes its toll. Here's a clue to help you decide if you need a new one; there is steam and water everywhere - the wife tells you to put it away - and it hardly turns over.