Installing piston ring

[vera]

I guess I could get the old ring off... explosives or something... but what I wanna know is how to put the new one on without messing it up or messing the cylinder liner up.

I asked OS about this and they say there is no tool for this job. They say...

It is recommended to install the ring into the groove starting at the
ring gap, then carefully working your way around the circumference of
the ring groove.

Well sure, I guess I would start at the gap... as opposed to cutting a new one. But if I do what I imagine they're saying, I'm gonna have to expand that ring gap to nearly the diameter of the piston. I don't know much about these things but I can't help feeling that the piston ring will stay expanded... or break.

I was hoping to find a tool for this job, something that would spread the ring just a little, enough to slip the piston in... something like one of those retaining ring pliars.

Has anyone here replaced a piston ring?

[BarracudaHockey]

There's no tool, just lay it over top of the piston, put one end in the groove at the index pin in the groove and gently work it around the top.

[3D Heli ireland]

You will find yourself holding your breath when you do the job waiting for that fatal crack noise that tells you you have wasted your time......One thing not to worry about however, the ring won't stay expanded........it will break!

Put the ring on as stated above, feeding it bit by bit into the groove making sure you fit the ring in the correct position and everything should be peachy....good luck :D

[Pinecone]

Hmm, someone needs to make a model sized piston ring installer. For full size motors it looks like pliers, but open when you squeeze. The ends have little L shape (laying down) such that the two short ends go between the ends of the ring at the gap and the ring lays against the long parts.

Gently squeeze and expand the ring evenly over the entire ring. SLide over pistion, release pressure and ring is installed, safely quickly.

Of course when you have to deal with 40 rings for one build, things like this become more important.

[Skiddz]

I've got one of those.. Got it in my hot-rod days when a motor rebuild was a 3 or 4 times per year occurance. Glad I held on to it 'cuz it sure came in handy when I rebuilt the engine in my wife's car a couple years back.

I wonder if some split-ring pliers would work on a model engine.. Just modify a set of jaws to capture the ring...

[TMoore]

It's not neccessary to use a tool to install a ring. Just spread the ring enough to get it over the groove and it will go. I've done hundreds that way.

TM

[Pinecone]

Skiddz,

As I ws writing I was wondering the same thing.

And TMoore, yes, I have done a lot of rings the same way, but the tool is much easier. :)

[Skiddz]

Great minds think alike!

Funny, when I rebuild a car engine, I use the ring tool. When I rebuild my 4 wheeler's engine, I always use my hands..

[Ivan]

If you lay the gap in the groove and work the ring around the piston, both sides simultaneously, it expands the ring the least. Less than any other way I have found. When trying to start with one end and work all the way around the piston is when I break rings.

Ring pliers usually end up sending the ring into a low earth orbit, and atmospheric re entry is not sufficient enough to keep the ring from shattering upon landing. That is my experiance anyway.

Also on a model engine, be sure to keep an eye on the pin that keeps the ring from spinning, and make sure the gap is over that, or you will break it upon insertion into the cylinder.

[BarracudaHockey]

Also on a model engine, be sure to keep an eye on the pin that keeps the ring from spinning, and make sure the gap is over that, or you will break it upon insertion into the cylinder.

Ah yes, one of my favorites. "the piston wouldnt easily slide into the liner, I beat it on with a mallet but now the piston will barely move up and down...."

[flyinfool]

A ring spreader type tool will not work on this ring.
A spreader type tool requires the the ring be spread open far enough to fit the piston OD inside of it. The ring will break before you get that far. Been there done that, still have a special custom made ring breaking tool.
By starting one end and working your way around, the ring does not have to spread as far open.

I beat it on with a mallet
:lolol
If it don't fit, you are obviously not using a big enough hammer. :arggg: :dontknow

[Ozmodeller Snr]

A ring spreader type tool will not work on this ring.
A spreader type tool requires the the ring be spread open far enough to fit the piston OD inside of it. The ring will break before you get that far. Been there done that, still have a special custom made ring breaking tool.
By starting one end and working your way around, the ring does not have to spread as far open.

I beat it on with a mallet
:lolol
If it don't fit, you are obviously not using a big enough hammer. :arggg: :dontknow

I have been using a home made ring expander for some years now with complete success. :wink:

Mine consists of coke can (typical) material cut down to slightly less than the diameter of the piston and cleaned of any burrs etc. I then roll the can material around the piston and form a small taper at the top of the material, fit the ring and slide it down the piston lining up the ring gap with the pin.

This works well for me and I have never broken a ring this way I have however, broken a few using the other method.

Cheers

Peter