cylinder scoring?

[Sabertooth]

Had a slow day in the garage and was cleaning up my saws. I decided to pull the plugs to see how they were burning out of bordom. All were burning that nice roasted brown color. I looked in one of my 369's cylinder with a flashlight, and saw " rings" going horizontal. Almost like someone tapped the thing for screws. They aren't really deep looking at all, but its noticeable.

I may not know what i'm talking about, but I'm quite sure all cylinders are smooth. They are on all my other saws at least :jester:

Any idea what that it? Doesn't look anything like normal scoring to me. Saw runs perfect, always has.

 

[watsonr]

Need a picture to be sure of what your asking. It may be machine marks left behind when they made the cylinder and piston.

 

[Jacob J.]

369? I'd like to see that one for sure.

Modern Nikasil plated cylinders will have horizontal lines on the walls when the cylinders are new or fairly new. These are marks left by the final honing of the cylinder during the "sizing" process, where the walls are sized to whatever specifications. If your cylinder was truly scored- you'd know it by how it runs or doesn't.

 

[Sabertooth]

369? I'd like to see that one for sure.

Modern Nikasil plated cylinders will have horizontal lines on the walls when the cylinders are new or fairly new. These are marks left by the final honing of the cylinder during the "sizing" process, where the walls are sized to whatever specifications. If your cylinder was truly scored- you'd know it by how it runs or doesn't.

This saw has over 4 years of hard work, and has good compression. I just found this strange for the cylinder to look like this. I have removed my 5105 muffler and saw this on the piston also, but it was more clear it was made that way.

I'll try to upload a pic tomorrow, but it may be hard to get a pic from the plug hole.

 

[TreeGuyHR]

I attempted to check out my 084 which the shop mechanic said had "some scoring". Couldn't see any. Does anyone use a special camera to peak in the spark plug hole? Seems to me this would be convenient, in order to avoid replacing the gasket on the head (which I assume was just done!)

My attempt:

View attachment 268777View attachment 268778

 

[bejay]

while kinda expensive a bore scope could be used to view the cylinder condition.
Choosing a Borescope

 

[TreeGuyHR]

while kinda expensive a bore scope could be used to view the cylinder condition.
Choosing a Borescope

I like it -- but no price on the page -- gonna be expensive!:msp_w00t:

 

[cutforfun]

I attempted to check out my 084 which the shop mechanic said had "some scoring". Couldn't see any. Does anyone use a special camera to peak in the spark plug hole? Seems to me this would be convenient, in order to avoid replacing the gasket on the head (which I assume was just done!)

My attempt:

View attachment 268777View attachment 268778

If you pull the muffler you should be able to see whats going on.

 

[BDM53ENT]

If you pull the muffler you should be able to see whats going on.

You can pick up a led light with a flexible shaft for about 15 bucks to see better in the cylinder. That and what Cut suggested will give you a really good idea of whats happening without going to the expense of a bore scope.

If you have to money to spend on a scope, they cant be beat and are REAL nice to have.

 

[TreeGuyHR]

You can pick up a led light with a flexible shaft for about 15 bucks to see better in the cylinder. That and what Cut suggested will give you a really good idea of whats happening without going to the expense of a bore scope.

If you have to money to spend on a scope, they cant be beat and are REAL nice to have.

I just realized that the fiber-optic lamp I have for my dissecting scope might work (use it in identifying insects and what not). So I took the muffler off (the inner screws were really tight and covered with carbon -- the mechanic obviously hadn't been in there!).

Got some pics that at least show streaks of crud, if not metal scoring:

View attachment 268794View attachment 268795View attachment 268796View attachment 268797View attachment 268798

BTW, is the muffler supposed to have a gasket on the surface where it mates to the head? Just seemed to be crud there.

 

[TreeGuyHR]

Any word on the gasket?

I am gonna put her together today, 'cause I'm having a party and someone might be inspired and do me the favor --- I would probably take it apart again just to make sure that there isn't a beer cap inside! :msp_tongue:

I'll just wipe the crud off and bolt it up (two in deep by the intake and one in each corner of the cover, plus a fat short one on the side that bolts to the saw case). Just hope my groundie didn't lose any bits -- he took everything off the floor where I had everything carefully laid out and piled it on a counter. You try to train them. :bang:

I measured a champion tree (that I was essentially removing, leaving a 20 - 30 clump from a 94 honey locust), while my guy was in a crane basket at the top; he dropped down a throw line and I tied a knot in it to get the exact height of the tree. I didn't get to measuring the string until my groundie untied the knot and carefully flaked the cord into a folding bag.:bang:; he HAD seen me throwing fits over tangles before, so it:kilt: goes.