Reusing piston rings? - CS Lister

G'day there. I've just got around to pulling apart an old CS Lister engine I acquired. Luckily I live in country Australia and therefore rust is not a major problem. However, mud wasps had blocked every hole possible. The water jacket was not spared. I have cleaned most of the nests out. The top quarter of the cylinder has a little bit of surface rust. Not too sure how I should go about there. The top of the piston appeared to be a bit rusty however the majority of it was easily brushed off. My question is if the piston rings look okay, is it advisable to reuse them? The engine's serial number is CS21995, which if I'm correct means it was built between 1936 and 1937. Please correct me if I'm wrong. According to the plate it is a 3HP engine. Would that indicated a 3/1? The RPM is 600.

Thank you
Koshy

Dear Koshy, You can re-use piston rings. To check if they are worn out or not and after everything has been cleaned up, put each piston ring into the cylinder liner and measure the gap between the butts of each piston ring. Record the measurements obtained. Then put the piston ring onto the piston (be careful not to snap a ring. - they are fragile when over expanded.) and measure the average gap between the top of the piton ring and the top of the piston ring grove, around the piston. Record the measurements as well. Then refer to the manufacturers recommended tolerances of wear. If you are inside the manufacturers tolerances of wear you can reuse the piston rings. The ring that will wear the most is the top ring, as it is subjected to the highest pressure. The oil control ring is one that also wears at a different rate than compression rings. As long as the piston rings look good and they fall into the specifications recommended by the manufacturers, there is no reason that they cannot be re-used. I have reused many piston rings and had good results, especially if the engine is not going to be used hard for long periods of time and you are not overhauling the engine for commercial reasons. Your engine will no doubt only be used for shows with a light duty rating. I hope that this helps you. Best regards, Geoffrey Owen from Namibia.