Piston ring verification

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Cobus

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Does anyone know of a saw builder that cuts a groove in their rings??
 

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The builder didn’t cut it in. That particular ring was made that way. @Jacob J. will probably know what they’re for
Hyway was (and maybe still is) doing that to their rings. I think the theory was that they trap and pin more oil to the cylinder wall. I don't use them - I think they're garbage.
 
I’ve only seen them in pics. Can’t say as I’ve ever run across them on the bench
That’s crazy because I know this faller paid good money for this build. I guess I’m judging on hyway rings when you can get caber.. So I went to my Stihl dealer and bought new rings.. and now I have no compression with brand new rings and before I had 125 with the grooved rings. And yes I made sure of the correct procedure to checking compression fellas. And the piston measures out as a 440 so something is off either I got sold the wrong rings or my hornady calipers went bad but my hand loads are still drivin tacks.
 
That’s crazy because I know this faller paid good money for this build. I guess I’m judging on hyway rings when you can get caber.. So I went to my Stihl dealer and bought new rings.. and now I have no compression with brand new rings and before I had 125 with the grooved rings. And yes I made sure of the correct procedure to checking compression fellas. And the piston measures out as a 440 so something is off either I got sold the wrong rings or my hornady calipers went bad but my hand loads are still drivin tacks.
What saw is it? What was the end gap measurement of each set of rings?
 
Correct me if I'm wrong, but won't they do a better job of retaining oil? In my 1-51 McCulloch (one of the high performance 80cc saws) the piston had similar grooves machined into the piston while the lower performance saws do not. To me, that would imply the designers felt there were gains to be had from adding extra grooves to the piston.
 
Correct me if I'm wrong, but won't they do a better job of retaining oil? In my 1-51 McCulloch (one of the high performance 80cc saws) the piston had similar grooves machined into the piston while the lower performance saws do not. To me, that would imply the designers felt there were gains to be had from adding extra grooves to the piston.

McCullough did some intelligent things. And they used high quality materials.

These rings pictured are just plain Chinese junk. There's no other way to put it. Crappy material, crappy workmanship....just junk.
 
What saw is it? What was the end gap measurement of each set of rings?
Ms 440 and I don’t know the end gap. I didn’t measure. The piston and cylinder are in good shape kinda figured it was time for new rings. This saw has a million miles on it and I’m actually decently impressed with how little carbon build up there was, cleaned the piston and cylinder up in about 10 min.
 
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