Ryobi piston rings needed

[scooterbum]

Hello folks,

I am in need of piston rings for a Ryobi SS 30 pole saw power unit. The old rings measure 1.4mm x 1.4 mm (0.056")and are for the 30cc cylinder.

I can't seem to find a supplier.

Alternately, I would be willing to purchase a replacement cyl kit, if one is available.

Many thanks.

 

[Al Smith]

Try this https://www.ereplacementparts.com/ryobi-ss30-ry30002a-string-trimmer-parts-c-7931_15633_15652.html

 

[Shane¹]

What size is the bore?

 

[scooterbum]

Try this https://www.ereplacementparts.com/ryobi-ss30-ry30002a-string-trimmer-parts-c-7931_15633_15652.html

I have tried them, and another supplier. Both suppliers sent the wrong rings (very thin rings).

 

[Al Smith]

Also e-bay and amazon part number 690161005 .---easy as pie

 

[scooterbum]

What size is the bore?

1.435"

 

[scooterbum]

Also e-bay and amazon part number 690161005 .---easy as pie

That part number brought me the wrong rings, twice.

 

[Shane¹]

So would they be 36mm rings? And are 1.4mm thick? So did they used to be 1.5mm and are worn? Do you have a 1.5mm ring you can try to stick in the grove and see if it fits?

 

[scooterbum]

So would they be 36mm rings? And are 1.4mm thick? So did they used to be 1.5mm and are worn? Do you have a 1.5mm ring you can try to stick in the grove and see if it fits?

The rings they sent are 0.58mm, and not compatible in any way to fitment, even if stacking.

One tech I talked with called Ryobi, who said there was a design change of these rings (piston?). Perhaps a later model SS30 had a different piston.

 

[Shane¹]

What does the piston measure? Is it closer to 36mm? I think you could use 36x1.5mm rings and be fine

 

[scooterbum]

What does the piston measure? Is it closer to 36mm? I think you could use 36x1.5mm rings and be fine

The piston skirt measures 36.41mm.

Online suppliers list 3 measurements for their rings, which to me is confusing. But nonetheless, the part number and "fits this" is listed as good to go.

 

[scooterbum]

The piston skirt measures 36.41mm.

Online suppliers list 3 measurements for their rings, which to me is confusing. But nonetheless, the part number and "fits this" is listed as good to go.

For example, they might list 5 x 1.5 x 1.5. What is the "5". MMs, inches, bore, what?

The bore measures 36.5mm, and the rings are 1.5 x 1.5.

 

[drf256]

What’s the end gap on the current rings? Why are they in need of replacement?

Can you buy a new piston and rings as a package?

 

[scooterbum]

What’s the end gap on the current rings? Why are they in need of replacement?

Can you buy a new piston and rings as a package?

End gap? Why do you ask?

Smarty me, I broke a piston ring so that I could clean the groove while waiting for my new rings to be delivered. New rings wrong size! uh-oh.

If you can direct me to a site that sells the package, or a complete top end, I will go that route. I haven't found that site.

 

[Shane¹]

Looks like caber makes a few 36.5mm rings can't find any super readily available but they are out there

 

[Al Smith]

Somebody certainly makes them I would think . If you can find the specs,which I could not try 690161002 .Evidently the engine or a varient was used on trimmers, blowers , pole saws .Also listed under Toro ,Homelite .For that matter you could probabley run it on one ring if nothing else.

In my collection of stuff I do have a Ryobi trmmer but it's 31 cc .Powerfull but I don't use it because it's a string head and I like blade heads .

 

[Wonkydonkey]

I had a Honda ex350 generator to fix up, cheap for a mate . Someone had ran it without any oil (100:1) or it had an air leak ?. Probably the former…
The piston was nasty.
I opted to sand the rough high spots on the piston.
those rings were 1.4mm thick according to the online parts list and i couldn’t find any that were in stock… and those Honda prices are pricey
so I ended up getting 1.5 mm thick rings and putting some 240 sandpaper on a glass sheet, then went round and round in an oval fashion till they fitted

It worked and has been run for a few hrs since…

So if your at a loss you could try this

Edit : Or run it on one ring as said above, like a lot of guys do in racing.. btw this generator is running on one ring

 

[Al Smith]

It's not a big deal to surface grind a ring for thickness .Fact I had it done over 50 years ago for an Indian motorcycle .However it would be big deal to add thickness .
I would think on things like blowers, pole saws and weed eaters unless to got real stingy with the oil ratio they should last almost forever . For that matter it takes a lot of use with a chainsaw engine to wear out the rings .Usualy they fail from a lean run or a restricted exhaust but a skimpy oil ratio doesn't help matters .

 

[scooterbum]

Looks like caber makes a few 36.5mm rings can't find any super readily available but they are out there

View attachment 385458

View attachment 385459

Shane,

Good catch! That appears to be the correct ring. However, on their site they do not list the axial and lateral dimensions, only 36.5 x 1.5. I would like to verify 1.5 x 1.5. Probably the right rings. Being in Athens, Greece they may be difficult to reach by phone?, to verify dimensions. $22.40 for 2 rings, tx, and snail mail ship.

Can you think of another, but local, supplier?

many thx.

 

[scooterbum]

i will be ordering a new ring for my Stihl 017, which is 37mm. I was thinking I could slip that old 017 ring into the second groove, hone, and return Ryobi to service. Would need to file end gap, and wall tension should not be too great, as that saw has seen adequate service life, so tension should be reduced. The Stihl cyl and piston looks great, so I would expect good results in the Ryobi with that ring. Side clearance is showing 1.5 thou. Is that enough clearance?

I know, I know, new rings would be best. And I may go there. But the gray matter never seems to rest with me.