Be NICE "IT" (Not Him/Her)
Cleaning Up Scored Cylinder???
- Thread starter seagiant
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Clean up transfer in a cylinder? Absolutely. As long as there are no gouges into the cylinder.
Now let's get this straight about joining. Unless you use a rigid home on a machine you will not oversize a nikasil cylinder.What you must do is break the GLAZING in the cylinder. New rings will not seat in a used cylinder without deglazing.
I had a customer bring in a MS460 that a "buddy" put in a new piston. Low compression, ran like crap. No leaks, carb looked good. Deglazed the cylinder only. Compression came up fro 75 to 150. Ran like new. The rings must seat for compression. Need a slight deglazed roughness to make it happen. I use a spring loaded small engine hone. It would not oversize a cylinder in days.
(Gets down of the soap box).
Now let's get this straight about joining. Unless you use a rigid home on a machine you will not oversize a nikasil cylinder.What you must do is break the GLAZING in the cylinder. New rings will not seat in a used cylinder without deglazing.
I had a customer bring in a MS460 that a "buddy" put in a new piston. Low compression, ran like crap. No leaks, carb looked good. Deglazed the cylinder only. Compression came up fro 75 to 150. Ran like new. The rings must seat for compression. Need a slight deglazed roughness to make it happen. I use a spring loaded small engine hone. It would not oversize a cylinder in days.
(Gets down of the soap box).
Don't need a hone, wet/dry paper with your fingers will take off the glaze. Hones can do more damage than good, you don't need a cross hatch like cast iron
Pics of NOS Stihl, note how smooth, not "roughed up" or cross hatched
034
048
Italian Tecomec 038M
Clean up transfer in a cylinder? Absolutely. As long as there are no gouges into the cylinder.
Now let's get this straight about joining. Unless you use a rigid home on a machine you will not oversize a nikasil cylinder.Wjat you must do is break the GLAZING in the cylinder.
Now let's get this straight about joining. Unless you use a rigid home on a machine you will not oversize a nikasil cylinder.Wjat you must do is break the GLAZING in the cylinder.
That is a new cylinder. Not glazed. Rings will seat to a new unused cylinder.
Hi,
Well, I think I am done and believe it will work.
Bought a small sanding flap wheel for my Foredom Tool and that helped! (Thanks Redneck!)
Took a Telescoping Gauge and does not look like I "egged" anything, still seems to be round, that plating is pretty tough!
Here is a pic, I can not really feel anything on the surface and sure can't, catch anything with my finger nail?
Oh yea, my OEM Piston showed up!
Well, I think I am done and believe it will work.
Bought a small sanding flap wheel for my Foredom Tool and that helped! (Thanks Redneck!)
Took a Telescoping Gauge and does not look like I "egged" anything, still seems to be round, that plating is pretty tough!
Here is a pic, I can not really feel anything on the surface and sure can't, catch anything with my finger nail?
Oh yea, my OEM Piston showed up!
Use as 120 or 80 grit sand paper, you want to scratch the transfer off as fast as you can. The finer the grit the better chance of getting thru the chrome and you don't want that, 80 grit will take the aluminum off fast and you can see it working. Use a small piece and your finger. A nice fine file on the piston is better than sand paper which will imbed the grit. 
Hi,
Well, put it all together, pulled the flywheel to test the crankcase pressure.
Waiting on a clutch removal tool, but decided to pressure test anyway just to see if it leaked...It did.
Crankcase Seal on the flywheel side was good, found a leak at the Decomp Valve.
Pulled, cleaned, and reinstalled with gasket maker and will wait a day for it to dry.
If it still leaks, probably get a new one.
That's where, I am at so far.
If the leaking Decomp Valve was the reason for the scored piston, I do not know?
Well, put it all together, pulled the flywheel to test the crankcase pressure.
Waiting on a clutch removal tool, but decided to pressure test anyway just to see if it leaked...It did.
Crankcase Seal on the flywheel side was good, found a leak at the Decomp Valve.
Pulled, cleaned, and reinstalled with gasket maker and will wait a day for it to dry.
If it still leaks, probably get a new one.
That's where, I am at so far.
If the leaking Decomp Valve was the reason for the scored piston, I do not know?
hacksaw and an 11/16 1/2 inch medium length socket you can make one(clutch remover) in 5 minutes.Also the Echo decomp is a weird thread pitch I think.
Hi,
Thanks, I just tested again, and the Decomp is now sealed, but still losing pressure somewhere?
Decided on a real clutch tool so I did not destroy anything.
If the leak is not the seal, under the clutch, then I'll have to look harder?
Thanks, I just tested again, and the Decomp is now sealed, but still losing pressure somewhere?
Decided on a real clutch tool so I did not destroy anything.
If the leak is not the seal, under the clutch, then I'll have to look harder?
Check the seal on the flywheel side.
Hi,
As I mentioned, it is good.
No, of course not. He's a 38-yr. licensed small engine mechanic, who also builds drag race engines. Perhaps my machinist skills are over-kill, when it comes to a $200 chainsaw. Buying new parts isn't always the true logic, if the parts are being applied to something with little value going in....
I'd love to see photos of that jugs renewed mirror finish..........and their absence will speak volumes.
Where is Dunedin?
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It is where everyone walks around sporting Presbyterian smiles.
City on the pimple of the lower East Coast of the South Island of New Zealand, possibly has a few Trolls living under old stone bridges in the Botanical Gardens.
new oem cylinders and some aftermarket have a nickle coating on top of the bore plating that wears away on start up revealing the fine crosshatch created at the end of cutting the bore to size. Running a ball hone through the used bore gives a microfine surface of peaks and valleys for the rings to mate into and seat vs a used bore thats polished/glazed and slick that a new ring can not instantly bite into and rapidly wear against requiring many hours of use to gain full compression. The ball hone deglazes, crosshatches and smooths chamfered port edges, if you are porting a cylinder you should be using one.
BrettS
ArboristSite Operative
At least it's better than AucklandIt is where everyone walks around sporting Presbyterian smiles.
City on the pimple of the lower East Coast of the South Island of New Zealand, possibly has a few Trolls living under old stone bridges in the Botanical Gardens.
What is going on with Auckland, stayed a night there and got bored so I took a ferry ride at midnight. Next day I went on a tour of the harbor in a little steam engine powered boat and that was awesome. Back in 2002. My other hobby is making steam engines. 
BrettS
ArboristSite Operative
Who is ole "captain bruce"?......
