How much is scoring

[regulate34]

So I wanted to have a look at the cylinder on my ms460. Just pulled the muffler cover and had a look. Everything looks good but I am no expert.
On the cylinder wall. I can see very faint vertical lines. It don't look like damage. Just evidence of a up and down motion.
Am I being too picky? Maybe paranoid. Saw has about 40-50 tanks on it. Bucking firewood.

Saw runs great. 4 stroke at WOT

I tried to get a pic. But nothing shows up and it's hard to get it to focus

So what I am wondering is this scoring? Or just normal ware and tear.

 

[AKDoug]

You will know when it's seriously scored. The piston will look like someone went vertical on it with 24 grit sand paper. Those vertical lines you are seeing is very likely normal (can't confirm 100% without a pic). Just do a Google images search for "scored chainsaw piston" and you will see what I mean. BTW 40-50 tanks isn't much use at all. You probably aren't looking at new rings until ten times that.

 

[regulate34]

I looked at google and on the forum. Looks nothing like what guys are calling "scored". I have to look at a certain angle to see the lines.

I will try again to get a pic. Maybe the wife has better photography skills then I do.

 

[fearofpavement]

Put the muffler back on and go to bed. In the morning it will be ready to cut wood again.

 

[old-cat]

Little scratches like that are caused by TINY debris. Possibly stuff that got in at assembly or stuff that gets through the filter?
Too little to worry about.

 

[SS Sniper]

Could be machining marks? If they're very faint then that's what I'm thinking.

If you say they look like an up and down motion caused them, then you're probably looking at really small debris in there like old-cat said

 

[cedarshark]

Machining marks are horizontal. Slight vertical marks are normal but you may have toasted that piston and you should send it to me for further testing

 

[sunfish]

The rings are cast iron, running vertical up & down in the bore. This will leave a mark...

 

[PA Dan]

Here's what scoring looks like!

 

[regulate34]

Not

Here's what scoring looks like!

not even close to what I am looking at.
How do you guys get pictures like that. I can't for the life of me

 

[nmurph]

It's all scoring, it's just a matter of whether or not it's normal and insignificant or if it's terminal. VERY light individual vertical lines scattered across the face of the piston usually aren't anything to concern yourself with. They can be the result of carbon coming loose or build up around the ports. It can also be the sign of trash inside the motor. Broader burnished areas are usually the result of surfaces mating together and usually aren't a concern. Scoring from lean, over heating, or no oil situations will usually show a series of small vertical lines that are close together. That is the result of the piston getting hot enough to melt and some of the piston deposits on the cylinder wall and then acts as a gouge to remove more and more meat from the piston.

 

[Crow99]

Just a quick thought here... there's oil on the piston and cylinder walls which can produce false "tracking" that mimics faint scoring. Reach in with a clean Q tip and wipe across the tracks. If the lines disappear then it's the oil.

 

[PA Dan]

Not

not even close to what I am looking at.
How do you guys get pictures like that. I can't for the life of me

Zoomed in with my Galaxy S3. Just have to keep trying until you get the focus where you want it.

 

[Dan Forsh]

This is what cylinder scoring looks like (and transfer).

I took this pic with my crappy phone camera, couldn't get it with my normal camera, go figure.

 

[regulate34]

Dan forsh
What would the savarity of they amount if scoring be?
Mine is not even close looking like that.
Would you notice a power differance in a saw like in your photo

 

[PA Dan]

When its really bad it looks like this!

 

[Dan Forsh]

Dan forsh
What would the savarity of they amount if scoring be?
Mine is not even close looking like that.
Would you notice a power differance in a saw like in your photo

If I recall, that particular cylinder had a piston looking very much like the one in PA Dan's photos. This was as I bought it, not working. I've had saws that would still work with some scoring and transfer, not as bad as the photos, but once the smearing of the ally traps the rings in their landings (like Dan's) you'll pretty much lose most compression anyway. I'm not so experienced as a lot of the guys on here, but I now know that you can get a saw in reasonable running order with some quite significant scoring. I've recently managed to reuse one in very similar condition to the one in the photo (have to remove the transferred ally first though).

 

[cedarshark]

If the plating is gone(as in the pic above) I won't reuse a cylinder. It's amazing that most can be cleaned up,reused and work fine with a new piston and rings.

 

[Wood Doctor]

Here's the exhaust side of an 028 Piston after the saw was run without any muffler mounting bolts attached to the jug. Compression was down to 52 psi. Saw failed to run.


Upon inspection, jug was still good. Replaced piston and rings. Compression is now at 150 psi and saw runs like a songbird.

 

[kz1000]

Save yourself the misery, send me the saw (free shipping) and I'll send you a wild thing as a replacement. Free shipping on the wild thing!