C72 piston rings

[pc13cb92]

Hi, can anyone tell me if there are two diiferent types of rings on the C72. I bought a replacement set for my motor, but when I tried them on the piston they were too big to fit into the top two ring grooves, but the oil ring was the correct size. The ring set is the early type, and the previous owner has fitted oversize (s1) pistons. The bores are OK and I was just changing the rings because I had it apart.

[LOUD MOUSE]

The early pistons were different from the later ones. (1962?)
First ones had 4 rather than 3 rings then the first 3 ring ones had thicker top 2 rings.
Usually the give away is the part numbers start with C72XXXX. ........lm

Hi, can anyone tell me if there are two diiferent types of rings on the C72. I bought a replacement set for my motor, but when I tried them on the piston they were too big to fit into the top two ring grooves, but the oil ring was the correct size. The ring set is the early type, and the previous owner has fitted oversize (s1) pistons. The bores are OK and I was just changing the rings because I had it apart.