I have a real nice used stihl OEM 44mm cylinder from an 026 I think it is an early one as it does not have any casting on top of the head that would be drilled and tapped for the compression valve so not sure if this would be chrome or nikasil plated there are no gouges or anything on the walls it is near pristine but it is real polished I have a new OEM piston with rings I want to use with it but not sure best way to prep the cylinder I have read that honing stones are a no no so emery paper?? what grit is best??
Best way to prep cylinder for new piston rings
- Thread starter roccus
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windthrown
361 Junkie
If it is stamped Mahle or Stihl its Nikasil plated. Look on the sides for the name in the casting. Actually any OEM 026 cylinder should be Nikasil plated.
As for new rings, I would deglaze the jug lightly with emery paper using a drill. I use a 1/4 inch paddle bit with a 1/2 inch by 4 inch strip of emery cloth taped to it. Then let the emery cloth flap inside the cylinder as you move the drill in and out to get a nice cross hatching pattern on the cylinder wall. Maybe use #400 grit? I learned this trick from Mastermind/Randy in a post if his. It works well to remove aluminum transfer.
Here is an AS demo thread that Randy posted on how to do the emery transfer removal and jug prep:
http://www.arboristsite.com/community/threads/how-to-remove-aluminum-transfer-without-acid.248325/
As for new rings, I would deglaze the jug lightly with emery paper using a drill. I use a 1/4 inch paddle bit with a 1/2 inch by 4 inch strip of emery cloth taped to it. Then let the emery cloth flap inside the cylinder as you move the drill in and out to get a nice cross hatching pattern on the cylinder wall. Maybe use #400 grit? I learned this trick from Mastermind/Randy in a post if his. It works well to remove aluminum transfer.
Here is an AS demo thread that Randy posted on how to do the emery transfer removal and jug prep:
http://www.arboristsite.com/community/threads/how-to-remove-aluminum-transfer-without-acid.248325/
Justsaws
Addicted to ArboristSite
If there is no damage to clean up then there is no need to do anything to a chrome or NiSil plated cylinder.
drf255
BAD CAD
I use a brake cylinder hone adjusted at low tension followed by a scotchbright ball.
Give me a slight fine crosshatch and also piece of mind in a ported cylinder. If I missed any edge when I chamfered the plating, the stone should find and smooth it.
Haven't had an issue yet.
Give me a slight fine crosshatch and also piece of mind in a ported cylinder. If I missed any edge when I chamfered the plating, the stone should find and smooth it.
Haven't had an issue yet.
I agree I have done bike and auto engines and always do this so the rings seat properly on break in I was just not sure if nikasil should be treated any different I had read that nikasil is more porous than chrome and retains oil better and that a honing stone can fill the pours in the nikasil and ruin it.....
jmssaws
Addicted to ArboristSite
There honed at the factory also
Justsaws
Addicted to ArboristSite
The process of manufacturing a new cylinder leaves the cylinder with a cross hatch pattern.
If you are adding a crosshatch pattern to a bore that is in good condition but smooth all you have done is make a bore bigger and plating thinner.
Should not need a cross hatch to break in rings as the patterns are the result of lines material being removed thus less material contacting rings. Nickel being exposed is moot and Sil being exposed below the rest of the surface is also moot.
In terms of oil retention, maybe it helps however it does not seem to be needed as is evidenced by your cylinder having no damage, and in any event more oil on the wall the longer break in will take.
Cross hatching may increase the amount of time it takes the rings to break in and increase the overall amount of time before the next set of rings and or piston is needed. A smooth bore by common thought should hold less oil and be more abrasive than a cross hatched bore, thus "broke in" and at its optimal condition.
If you want to crosshatch it go nuts. I use lots of different hones, mandrels and abrasives and have yet to ruin a bore unintentionally. I generally use scotch brite pad type products to clean them up a bit for inspection. It takes some effort in my opinion to ruin a good plated bore. Less effort if people are using chemicals to remove transfered piston material, porosity of plating is real.
If you are adding a crosshatch pattern to a bore that is in good condition but smooth all you have done is make a bore bigger and plating thinner.
Should not need a cross hatch to break in rings as the patterns are the result of lines material being removed thus less material contacting rings. Nickel being exposed is moot and Sil being exposed below the rest of the surface is also moot.
In terms of oil retention, maybe it helps however it does not seem to be needed as is evidenced by your cylinder having no damage, and in any event more oil on the wall the longer break in will take.
Cross hatching may increase the amount of time it takes the rings to break in and increase the overall amount of time before the next set of rings and or piston is needed. A smooth bore by common thought should hold less oil and be more abrasive than a cross hatched bore, thus "broke in" and at its optimal condition.
If you want to crosshatch it go nuts. I use lots of different hones, mandrels and abrasives and have yet to ruin a bore unintentionally. I generally use scotch brite pad type products to clean them up a bit for inspection. It takes some effort in my opinion to ruin a good plated bore. Less effort if people are using chemicals to remove transfered piston material, porosity of plating is real.
jmssaws
Addicted to ArboristSite
I've measured the bore on a mountain of cylinders,most of them 066/660 and a brand new one or one that is 20 years old with a lot of time on it will measure just about the same.
If your changing the size of the bore with a hone then you for one have a better hone and drill than I do and your spending time on it.
Over time it will build a film on the plating that I like to sand off but to each there own.
If your changing the size of the bore with a hone then you for one have a better hone and drill than I do and your spending time on it.
Over time it will build a film on the plating that I like to sand off but to each there own.
windthrown
361 Junkie
Yep, that is why I do some emery spinning just to take the surface crud off. There is usually some transfer in there, as seen by light vertical marks on the jugs. I would not use a honing stone, just fine grit emery. I also like stiffer rings, and I prefer Caber to OEM.
jmssaws
Addicted to ArboristSite
I like cabers the least. I like softer rings,the coated Hyway rings are my favorite
windthrown
361 Junkie
I will take stiffer Italian rings over Chicom softies any day. I have woken up so many tired saws with Caber rings (made by Meteor) it is not even funny. I also like Mahle jugs over any other. Viva l'Italia!
I thought Caber was OEM for stihl??? The cylinder he re is in great shape even the piston is pretty good only signs of wear on it are on the exhaust side at the bottom of the skirt is is worn smooth to where the little ribs the oem pistons have has been polished smooth from wear I can see in the cylinder has high polished look where the piston rides more notably at the bottom of the cylinder where the bottom of the piston contacts the walls of the cylinder... I guess there are pros and cons to every action both points made here sound valid
Justsaws
Addicted to ArboristSite
A cylinder bore should not change dramatically during use. Open transfer ports and small bores seem to change the most. Usually the area that the ring travels is the most affected. Tend to check them over with a fine wire pick as I generally cannot see the shift on the bore wall, oddly enough 1121s are one of the small bore saws that I have found to need a close inspection. However many of the 1121s are at least on their second piston. Typically on open ports the piston will be well shaped to the bore and as such the bore should be suspect as well. Generally speaking 1129s and 1127 series are a good example of this. If you are using ring end gap to check the bore then it needs to be done st the top, middle and bottom of the ring travel on a suspect cylinder while keeping the ring gap in the same viewing position, as well the "glazed" area around transfers and such that does not come into contact with the rings and piston should be avoided while taking measurements for ring gap.
In terms of large bore closed port very seldom see one that is beyond a listed spec for ring end gap. 1122s are typically good for a couple of pistons. I have bought quite a few 395 pistons, almost never need the cylinder and if I do it has been because dents and dings.
In terms of cleaning up the scum layer to expose a fresh wall, at best the layer of scum is comprised of alum., steel, wood, oil , nickel and silcarbide or chrome. All of it needs to be smaller than the porosity and surface texture of the coating to exist and again honing will not remove it beyond the visible lines left by the hone. As well it is not an issue if the bore is in good condition.
My personal opinion is it should take a bit of effort to mess up of plated bore. I see no great advantage to honing a good bore and certainly see no disadvantage in not honing.
In terms of large bore closed port very seldom see one that is beyond a listed spec for ring end gap. 1122s are typically good for a couple of pistons. I have bought quite a few 395 pistons, almost never need the cylinder and if I do it has been because dents and dings.
In terms of cleaning up the scum layer to expose a fresh wall, at best the layer of scum is comprised of alum., steel, wood, oil , nickel and silcarbide or chrome. All of it needs to be smaller than the porosity and surface texture of the coating to exist and again honing will not remove it beyond the visible lines left by the hone. As well it is not an issue if the bore is in good condition.
My personal opinion is it should take a bit of effort to mess up of plated bore. I see no great advantage to honing a good bore and certainly see no disadvantage in not honing.
The original Caber rings are fine. It's the F-Cast that are much stiffer that I don't care for.
I have the cylinder and piston just for back up my saw is running good and no scratches or scaring that I can see from the exhaust port I was able to get a real good deal on these parts so grabbed them thinking about maybe sending it some where for porting but nor sure if it is worth if you really get that much more out of it... from reading what has been posted in this thread I never realized there were differences with the rings I just assumed the only difference between the better rings and the china cheep ones was fit
