Cylinder clean up question

[xxl]

I have cleaned a few cylinders up and have had good results. My question is when you clean them up and get them all shinny and new looking. Do they stay like that or will they sometimes still have lines where the transfer used to be. One saw I have about 20 tanks thought and we have ran 30 inch bars and no issue there are no indications on the piston of scoring . Another has had alot more use no issues so what has every one else seen on cylinders

 

[Al Smith]

Well if you cut to the chase it boils down to good air filtration and proper oil ratios in the fuel .I just recently rebuilt a pair of Partner P-100's that date back to the late 70's early 80's .Not a blemish on either the pistons or the cylinders .Dirty air will eat them up as badly as too little oil in the fuel mixture .

 

[Nutball]

Just clean the aluminum off, and get back down to the plating. Any lines left over that aren't scoring marks are probably where the plating has been polished by the rings, or piston as it was seizing. I've heard where some people think their engine is scored after the first use, but those are just polished lines. They eventually go away after several hours of use, and the bore should look new again in an old saw.

 

[Magnus]

A bit alumium after scoring is often not hard to remove. Plating is tuff and very very thin. If plating is damaged in any way its done.
Honing etz usually don't di much with plating as its pretty hard stuff, if it does its gone as it's so super thin...

 

[Al Smith]

Generally speaking a good job of plating will hold up a long long time providing it has good lubrication and air filtration .Some of the older brands like McCulloch had some problems towards the end of their production with quality plating but it's pretty rare .You need to remember the function of a piston acts in a way like a slide valve in a linier bearing as well as a provider of power to the crankshaft were it is converted to rotational power .Oil BTW is the life blood of any engine from steam to diesel .Turbine or piston .Can't run long without it .

 

[Magnus]

Yes, it is very strong and Nikasil is almost impossible to wear out. Something else break first.

When piston get hotter than it should be sometimes aluminum get stuck on plating. Always combined with scoring and deformed piston/ring to some extent. Removing this is sometimes not as easy as other times. Mostly its no damages in plating, sometimes under ports and is of no real importance if its even and smooth. When surface/plating is clean its easy to see damages.
I use dremmel and 200 paper to get most alu out. then 500 grit on hole surface. It is not often polish cylinder but do occasionally if needed, but I have polished quite a bit pistons.

If you are worried you might damage the Nikasil, get a junked one and try to do damage on it.
A good way to learn and see...

When /if large chunks of plating is missing it has been bad from day one.

 

[Al Smith]

I would not say hard nickel is like armor plate because you can wear right through it .I messed up an 034 Stihl cylinder by using a flap wheel .To repair that one I used an 036 cylinder and an aftermarket piston .Had I not lost my patience and used a less abrasive method I could have salvaged it .It's a learning curve .

 

[Tree09]

Good heads up man!!!!

 

[Magnus]

Nicasil is very, very thin. A few hundreds of an mm... If you damage it in any way its gone.
But its very hard to get thru unless there is an edge tool can get to and rip it off.

 

[Marc-Antoine]

I tried the chemical way, as the aluminum can be destructed by both acid and alkaline solutions. Bad idea, even with care. That works, no problem, but if there's the slightest defect in the hard lay, tiny crack or pin point hole (even microscopic), the liquid goes through it and attacks the underlaying metal. The byproducts are trapped under the hard lay and peel it off locally.

 

[Nutball]

Nicasil is very, very thin. A few hundreds of an mm... If you damage it in any way its gone.
But its very hard to get thru unless there is an edge tool can get to and rip it off.

I think it depends on who made the cylinder. Some aftermarket cylinders use thin chrome, Echo looks to me like super thick chrome, farmer tech is super thin nikasil while Hyway is super thick. Then I've seen some nikasil peel while others chip. Bonding strength to the aluminum seems to be a variable issue.

I tried the chemical way, as the aluminum can be destructed by both acid and alkaline solutions. Bad idea, even with care. That works, no problem, but if there's the slightest defect in the hard lay, tiny crack or pin point hole (even microscopic), the liquid goes through it and attacks the underlaying metal. The byproducts are trapped under the hard lay and peel it off locally.

That's what I've always been afraid of.

 

[Magnus]

I have still to see a thick layer of Nikasil, It can't be thick, not even in the magical Hyway...
It will not work.
No one use chrome since late 80's. Not echo or anyone else in what I have seen.

If it peels its from bad production as in inpurety's in material under.
It has been seen on some cylinders that is made the last ten years, as manufacturing process changed quite a bit.

 

[Frankie]

20-50 microns is standard nikasil thickness ... Very thin !

 

[Nutball]

I have gotten the impression that Echos are quite silver looking inside while the obvious nikasil cylinders seem to have a slight goldish brown tinge. Not that I'm right, but it would seem so by color. US Chrome uses chrome, so it must be popular enough in engines today.

 

[Frankie]

Chrome plated cylinders are really “old-school” and like Magnus stated previously were 80’s tech ... Nikasil is FAR superior to chrome plating , in fact just about every modern pro saw uses nikasil to the best of my knowledge with the exception of ECHO - which is one reason I do not run echo 😂 ... If you send a cylinder to us chrome they will recoat with nikasil despite the name

 

[Magnus]

I doubt the Echo use chrome. Its likely nikasil The few I have seen made after 1990 had Nikasil.
In chromed cylinders you see were the rings turn after some runtime, in Nikasil you don't. Rings are not same in the two.
Nikasil coloring is mostly grey with sometimes some colors that fades/wear off.
If its run hot or with too hard rings you sometimes see a bit rainbow coloring, but then the rings are often shot as they run often have hot. Can be from lack of lubrication or wrong material, but either way not right.

 

[Frankie]

This echo 490 uses chrome plated cylinder

 

[Magnus]

I know they write that, I find it very hard to believe As it has been a very long time sine I have seen it in an Echo.
I find it hard to think they go back to an inferior more expensive way.
Nicasil is a form of chrome too you know...

 

[Frankie]

Nikasil was introduced by Mahle in 1967 ... It is short for nickle silicon carbide - If echo states they are using chrome cylinders than I believe them

 

[Magnus]

Other reading: NiCom (Nikasil) Cylinder Coating and Repair - US Chrome - https://www.uschrome.com/nicom-nikasil-cylinder-coating-and-repair

 

[Frankie]

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