Piston ring "slant"- up or down?

Nashville Kat

Nashville Kat

Well-Known Member
So we all soon learn to get the pins in the piston into the gap in the rings while putting the rings on-

but what about the "slanted" ends of the rings at the gap?

Should the close of the slant be at the bottom to "wrap around the rings at the top: \ /

or should the longer part of the rings close together at the top- to gain the most compression on the downward power stroke? (no keyboard characters for this example!)

Both ways seem to make sense- but I'm guessing it's easier to squeeze the rings together in the slanted portions wrap around the pin and face up: \ /

Probably less likely to break then.

Does anyone know FOR CERTAIN?

Tell the truth, trippy cyber-age millenials!scratg
 
This is frustrating- here is a youtube vid about installing the pistons and head on the site of an ebay replacement engine sold with the head still apart-

https://www.youtube.com/watch?v=CIfecTspJKQ

and the AUDIO is not there- so you just can't quite see the placement of the rings on the piston-

I found one good tip off another video- Install ONE of the pesky end "G" shaped clips in the piston BEFORE anything else- then at the end you only have to get the other in place on the bike- and put something under it so it doesn't fall into the bottom end!
 
I can't remember if its up or down but the position will be dictated by the locator pins. They will be your guide.
 
They were pointed up at the pins on the old one- Duh! I finally thought to look- and the pins are at the top of the grooves- so the rings wrap most around them apparently.

like this: \*/

Got the rings and piston on the rod, and the stupid G clips on and in their grooves- now struggling to get the jug over them- giving up for the night.

Can't believe they are selling the motor without the head installed on ebay these days!
The Conglomerate will sell us the stuff still, but doesn't make or hobby and transportation any easier I think.
 
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Yes, getting the jug over the rings is an exercise in slippery frustration. You can also smooth out the flare on the bottom of the jug (the cylinder skirt) and that might help a bit.
 
Got it on there- if I had to do it again right now I could probably do it about 10 times quicker- but if I ever have to do it again down the road it'll take about as long.

Did you see how fast the guy in the video did it? Like he's done it a million times before.

Just have to put the exhaust and intake back on- probably be getting it out tomorrow- Got the plug out and plan to ride it around a few hundred yards to be sure the rings are settling in right before I start it up. the old 42 X 22 freewheel set-up makes a pretty easy pedal....
 
Nashville Kat said:
They were pointed up at the pins on the old one- Duh! I finally thought to look- and the pins are at the top of the grooves- so the rings wrap most around them apparently.

like this: \*/

Got the rings and piston on the rod, and the stupid G clips on and in their grooves- now struggling to get the jug over them- giving up for the night.

Can't believe they are selling the motor without the head installed on ebay these days!
The Conglomerate will sell us the stuff still, but doesn't make or hobby and transportation any easier I think.
Click to expand...

Exactly Nashville Kat. NOW you got it.
 
Glad to hear you got it together. Yeah, repetition makes it go easier and it always amazes me how quickly my fingers forget what to do. Good luck on your maiden run! And that's a sweet Hummingbird. I have the exact same colour but mine is the Epiphone and it sounds and feels great. I can only imagine how nice the Gibson would be. Keep on pickin
 
The guitar is in fact also an Epiphone Hummingbird and I sold it a year ago or so. I started getting into smaller scale guitars and find them easier to play. It was a nice guitar, but the intonation was just a bit off moving up the neck- I found I was mostly playing my Rogue Honduran Mahogany model, if steel strings at all. Lately I'm playing the steel strings a lot- a Yamaha mini folk and a Rogue Starter 7/8 size. The full sized Rogue is also now up for sale, leaving me with only one full sized classical nylon string guitar and several smaller ones. Spending some time playing a Baldwin Hamilton studio upright piano I keep tuned up myself, and also fiddle. And trying NOT to spend as much time doing anything mechanical.

The piston replacement was stupid- The motor wasn't popping over quite as fast, so I pulled the plug and closed the gap a bit (and decided I'm running too much oli) then started off and it was running then very poor- so I turned around to put another plug in- grabbed one from the shelf I thought was a bit longer NGK or something- but it was a plug from my car! I thought it looked a little long and wondered if the piston might contact it- started off released the clutch, and heard it hit- Got off right away and tried the other one regapped- but I'd punched a hole in the piston top and didn't have compression.

I actually repaired the old one while waiting for the new, with some flux and a soldering iron, and it filled the small puncture so nicely, I'm sure it would probably work- even filed the top of it smooth again, you can hardly see a patch- but no sense risking the dross messing up the jug while I have a new replacement. Hope the rings settle in and don't break- don't want to have to buy a jug.
 
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Nash, What a coincidence, I also have a Rogue! It's a hollow bodied single cutaway with a resonator and one lipstick pickup. I also have a Taylor big baby which is my go to guitar because it's just a bit smaller than regular and is more comfortable to play sitting on the sofa. My brother is now on the hunt for a GS Mini for a travel guitar. I have about a dozen guitars (mostly in the one to two hundred range) and the pride of the collection are a 1977 Larivee, and a 1969 Fender Jaguar. Lucky I bought those two over thirty years ago otherwise I could never hope to afford them now.

I'm planning to break in a new engine this weekend. I got it in a trade off of craigslist. It's an 66cc kit that was never installed and came with a jackshaft kit that I'll sell or trade for an expansion chamber or something. I traded a huffy cranbrook and thirty dollars for the whole thing. I've just finished some minor porting and skirt shaving and it's ready to install. I plan to break it in fairly aggressively and see how that works out. Over the summer I'm going to build a new project with the phantom frame and Morini. The motor is older and not powerful but I'm expecting good reliability from it. It's in great condition and was well looked after.

Now I have to go over to a buddy's place and help him move some furniture around so I might be doing a one day break in tomorrow. I'll let you know how it goes. Good luck with yours.

Chaz
 
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