Step 10: Install Piston Rings
I actually figured this out weeks ago, when I first received the rebuild kit in the mail - because I was kind of freaked out about it. Here's the instructions that came with the piston and rings. I was... let's just say...nonplussed.
Then I started studying the ends of the rings. You have to be sure to study them from the same angle as the image - that is to say, holding the ring in the proper orientation and looking at the proper end. I took pictures of them to study against the image.
So here we see a ring with a 90 degree square notch in it, but it doesn't match up. That's because I was holding it wrong:
Flipped it over, and now it looks like this:
It's a match for the middle (oil scraper) ring - the last one in the row on the "instruction" sheet.
Here's the other one, a match for the top (compression) ring (2nd image top row)
And the bottom (oil lubricating) rings are obvious, the expander and the two thin rings (I only have the expander pictured here)
There is quite a bit of stuff on installing rings
halfway down this page, most of it very helpful, some of it a bit confusing.
I purchased this ring expanding tool
and ring compression tool
from Harbor Freight for $8 each. I actually only used the expander partially, and found it easier to start one end of the ring and "roll" (for lack of a better word) it into place by going around the piston and bringing it down.
The bottom set goes on first. And of that set, the expander goes in first. It has a "seat" on the backside of it that the two smaller rings rest on, so it must go in first. Don't overlap the expander upon itself, it's ends must butt up. Overlapping would make it fail.
And here's the middle ring installed.
I didn't get any pics of the top ring installed, but you get the idea. I staggered all four of the rings at 90 degree intervals.