Hi.
The three-ring piston was really only ‘listed’ for the 1939 Clubman Special, but no doubt stocks remained for years afterwards, and would be used as and when later pistons were out of stock, like when Hepolite’s bill had not been paid…..I am not really being cynical, but that is the way things often were.
By way of illustration, when Matt Holder bought the remains of the Shipley company in 1950, creditors came out of the woodwork wringing their hands like Uriah Heep, and the Fellowes Magneto company asked for payment of a bill going back to the early 1920’s, despite the fact that they hadn’t traded themselves for years! To his great credit, Matt paid them.
Two rings per piston is perfectly adequate.
Brian
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