Replacing only 1 ring, to hone or not to hone?
- Thread starter madrone
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harrygrey382
Addicted to ArboristSite
don't hone. And put the new one on top - it takes more of a beating. Out of interest, why are you only replacing one? I didn't even know you could buy them separately...
madrone
Addicted to ArboristSite
I pulled the cylinder and when re-installing the ring cracked, either from weakness or my mistake, i'm not sure.
They cost $23 per ring -OEM so I don't want to replace what I don't have to.
Why do you say not to hone?
Saw Dr.
Junk Collector
Crofter
Addicted to ArboristSite
You would need a very specialized hone to selectively remove material above the upper ring travel. We are talking nikasil or Stihls plating process, not a cast iron or steel cylinder surface.
The trouble with honing is removal of metal randomly or at the edge of ports and flaking the plating which is only a few thou thick. Failure of ring seating is not a problem in modern saw cylinders. I agree with Harrygrey 382. Forget the hone and hand scuff with 320 grit paper if you feel you must.
Lakeside53
Stihl Wrenching
yes...
madrone
Addicted to ArboristSite
Thanks for all the replies.
Now is when I get to admit that I am a chump and asked this question after the fact.
Here is the rest of the story:
I was pissed about the ring breaking as i needed the saw to run asap. I got the new ring and put it in (on the bottom) and ran a light hone in the cylinder. I probably did the hone for no other reason than because I have the ball hone and hardly ever get to use it.
I put it back together with lots of oil, no problems.
I ran the saw and tested compression. I used to pull 180 psi with my tester which is probably a bit high and now read 150.
Once again I have learned to ask first and do second and not to let impatience get the best of me.....BUT...
Do you guys think that after some break-in time it will come up to a decent psi or should I open it again, put in a second new ring and kick myself in the a$$?
Now is when I get to admit that I am a chump and asked this question after the fact.
Here is the rest of the story:
I was pissed about the ring breaking as i needed the saw to run asap. I got the new ring and put it in (on the bottom) and ran a light hone in the cylinder. I probably did the hone for no other reason than because I have the ball hone and hardly ever get to use it.
I put it back together with lots of oil, no problems.
I ran the saw and tested compression. I used to pull 180 psi with my tester which is probably a bit high and now read 150.
Once again I have learned to ask first and do second and not to let impatience get the best of me.....BUT...
Do you guys think that after some break-in time it will come up to a decent psi or should I open it again, put in a second new ring and kick myself in the a$$?
Crofter
Addicted to ArboristSite
Hey you are not the first one to break a ring!
You would have higher compression if you put it on the upper groove because all the space above the lower ring, including the upper ring groove is volume added to the compressed volume. Not a lot, but considering the combustion chamber volume is only around 6 cc it makes a difference in compression and unburned portion of the charge.
You would have higher compression if you put it on the upper groove because all the space above the lower ring, including the upper ring groove is volume added to the compressed volume. Not a lot, but considering the combustion chamber volume is only around 6 cc it makes a difference in compression and unburned portion of the charge.
stihl025
ArboristSite Guru
Why were you screwing with the piston and rings anyway? What happened that you had the saw apart?
madrone
Addicted to ArboristSite
Now yer gonna make me look real bad.:monkey:
willsaw4beer
Addicted to ArboristSite
Admittedly I am an idiot, so a good philsophy I've adapted is if it ain't broke don't :censored: with it (because then it probably will be.)
madrone
Addicted to ArboristSite
I don't get this. It's not as if the upper ring is shot, just not seated as well any more. I'm hoping the older ring will seat itself properly in time as well as the new one.
oh, please share the story !!!!
inquiering minds want to know............did i spewl that rite ?
madrone
Addicted to ArboristSite
Ok, this is the final chapter in my 361 ring saga.
Today I bought the other ring, pulled the cylinder again and popped it on. I'm getting good at this as it only took about 25 min.
The saw started on the 2nd pull and ran like a top. I threw the compression tester on there and it hit 170 psi, cold. As I said before the tester is screwy, so the number is only relative to what the saw used to read which was 180. If when the rings seat back in the compression gets close to what I had before, i'm stoked.
Lesson learned, you can't just replace one ring without a power loss.
Thanks all. hope this helps someone down the road.
Today I bought the other ring, pulled the cylinder again and popped it on. I'm getting good at this as it only took about 25 min.
The saw started on the 2nd pull and ran like a top. I threw the compression tester on there and it hit 170 psi, cold. As I said before the tester is screwy, so the number is only relative to what the saw used to read which was 180. If when the rings seat back in the compression gets close to what I had before, i'm stoked.
Lesson learned, you can't just replace one ring without a power loss.
Thanks all. hope this helps someone down the road.
Crofter
Addicted to ArboristSite
Madrone I had to go back and re read! I had it in my head that you ran it without the upper ring!
windthrown
361 Junkie
Thanks from across the river.
Note to self: replace both rings if any need replacing or are broken.
I would think that you should get the PSI back up when the rings seat.
Note to self: replace both rings if any need replacing or are broken.
I would think that you should get the PSI back up when the rings seat.
