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Rings were the topic of the day. The rings on this engine have some interesting features and if anyone knows how rings are made, please help us out here; it's interesting.
Quick background to this - we have the original pistons and rings, as removed, as well as a set of new but original (NOS) replacement parts. Some of the replacements are damaged but there's enough good stuff to put together this engine.
1. The gap between the ends of the rings is an overlap. The edges of the overlap are rounded, and there's about a millimeter to 1.5 mm between the edges looking at them circumferentially. Looking at them axially, there's almost no gap due to the overlap. The pictures show this.
Question - how were the ends of the rings made?
2. There are some manufacturing marks on the inside face of the rings, pretty much opposite the gap. At first glance these appeared to be a scale of some sort, but we decided that they were probably tooling marks.
Question - why are these marks there? Was it from tooling?
3. The rings are all like the one in the photos. That is, they're all rectangular cast-iron rings, one piece. Well, we thought that they were rectangular. Turns out that the top and bottom faces are slightly beveled, maybe a total of one degree between them. The inside edge is shorter than the outside edge, and the piston grooves match. It's intentional, because the new rings and the new pistons are that way, as well as the original ones.
Question - why was this done?
Incidentally, in the last picture below, the ring is resting on a disposable aluminum pan that's upside down. Just mentioning it because we wouldn't want you to waste effort trying to figure out what the pattern refers to.
Some of the piston pins from the unused new pistons will be used here to replace some worn original pins.
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