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Success after more than 5 years!

Started by joe_indi, June 06, 2014, 01:40:34 PM

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joe_indi

Many years go I had posted on my efforts to repair chainsaw cylinders with cast iron liners.

This is a link to that post https://forestryforum.com/board/index.php/topic,35059.0.html

Well so far success rate was a measly 5%. But I never stopped my experiments. After a lot of time effort and money lost, it was only quite recently that I hit upon the probable cause for the high failure.
We have been following the usual steps.
Bore the cylinder
Fabricate the sleeve
Press the sleeve into the cylinder
Hone the cylinder
.......well that is how it was being done, with all kinds of clearances each time.
I was having so many misses and very few hits.
After about 45 attempts when I was about to give up I realized the cause for the inconstancy.
Sleeves and honing are fine on engine blocks with separate heads.
Here the top end is closed so the result was tapered honing every time!
The bottom gets wide by the time the top is honed to proper clearance.
So each time the piston moves down hot gases enter the crankcase.
So, I found out the solution, it was so simple!
Bore the cylinder
Fabricate the sleeve
Hone the sleeve!
Press the sleeve into the cylinder.
I got the first one done this way and it works!
But the tricky part was finding out the diameter to which the sleeve had to be honed.
Well I had to sacrifice a sleeve and cylinder for that.
We honed a sleeve to exactly 52mm, used an hydraulic press to get it into the cylinder.
The 52mm diameter had shrunk to 51.8mm
So the next sleeve we honed to 52.2mm
And we got 52.02 in the cylinder, for which I did a polish by hand to get rid of that .02  extra.
It took 10 attempts to get the saw to start up. But once it started it never stalled.The engine beat went steadily from a rough weak idle to an increasing even firing till after 15minutes of idle and occasional blips of the throttle, it was running like a saw with a regular cylinder.
I tried it out on a couple of cuts.No heating or faltering.
Tomorrow it goes into the field for an extensive workout.
Cost of the sleeve as of today? About $.35/-

This is a picture of today's cylinder:

sablatnic

Looking good! Many old chainsaws used an iron liner too, so it can be done. Thanks for showing it!

Jiles

Very interesting---I have two Echo CS520 and both need cylinders. Strange that I am unable to find one on eBay or from many used chainsaw parts venders. New, it is close to $250.00!!
I am a retired T&D Maker with my own machine shop.
How did you mount the cylinder for boring?
Satisfy needs before desires

joe_indi

The tooling shop made a jig to which the cylinder is bolted on using the holes for the cylinder screws.
The jig is then fitted in place below a boring machine that is used on single cylinder engines

7sleeper

This is REALLY cool!!! Has to be one of the very very few threads of the year worthy of remembering! Which saw is it?

Can't wait to hear you experience! THANKS for sharing!

7

Al_Smith

I've done a few sleeves .The last was for a SP125 McCulloch the chrome had peeled .

As a general rule you cut the OD of the sleeve 1 thou over for every inch of bore then heat shrink fit .I used grade 50 fine grained gray cast iron which is the same grade Harley-Davidson used on 74 cubic inch flat head engines .

You're better off if you allow about 1 over on finished ID bore and use a precision hone such as a Lisle because the sleeve can deform a tad bit when being pressed in .I fitted the piston to around 3.5-4 thou clearance of the piston skirt which should be the widest portion of the piston .I certainly had more than the price listed though just in the material not to mention my time .

clww

Many Stihl Saws-16"-60"
"Go Ask The Other Master Chief"
18-Wheeler Driver

joe_indi


ladylake

Quote from: Jiles on June 06, 2014, 02:19:08 PM
Very interesting---I have two Echo CS520 and both need cylinders. Strange that I am unable to find one on eBay or from many used chainsaw parts venders. New, it is close to $250.00!!
I am a retired T&D Maker with my own machine shop.
How did you mount the cylinder for boring?

Online a new cylinder for a CS520 is $128.09  piston is $52.69 and a whole new short block  is $203.00. Steve
Timberking B20  18000  hours +  Case75xt grapple + forks+8" snow bucket + dirt bucket   770 Oliver   Lots(too many) of chainsaws, Like the Echo saws and the Stihl and Husky     W5  Case loader   1  trailers  Wright sharpener     Suffolk  setter Volvo MCT125c skid loader

Jiles

Quote from: ladylake on June 07, 2014, 09:15:24 AM
Quote from: Jiles on June 06, 2014, 02:19:08 PM
Very interesting---I have two Echo CS520 and both need cylinders. Strange that I am unable to find one on eBay or from many used chainsaw parts venders. New, it is close to $250.00!!
I am a retired T&D Maker with my own machine shop.
How did you mount the cylinder for boring?

Online a new cylinder for a CS520 is $128.09  piston is $52.69 and a whole new short block  is $203.00. Steve

WHERE??
Satisfy needs before desires

ladylake

 
SEPW   Small engine parts warehouse.   Steve
Timberking B20  18000  hours +  Case75xt grapple + forks+8" snow bucket + dirt bucket   770 Oliver   Lots(too many) of chainsaws, Like the Echo saws and the Stihl and Husky     W5  Case loader   1  trailers  Wright sharpener     Suffolk  setter Volvo MCT125c skid loader

Jiles

Quote from: ladylake on June 07, 2014, 10:15:08 AM
 
SEPW   Small engine parts warehouse.   Steve
THANKS--I searched their site and came up with MANY results.
I emailed them and waiting for response.
Can you give me their part number?
Satisfy needs before desires

ladylake

Timberking B20  18000  hours +  Case75xt grapple + forks+8" snow bucket + dirt bucket   770 Oliver   Lots(too many) of chainsaws, Like the Echo saws and the Stihl and Husky     W5  Case loader   1  trailers  Wright sharpener     Suffolk  setter Volvo MCT125c skid loader

ehp

Joe what rings are you using , ring that was made to run on chrome bore does not like cast iron, it will run but wears out fast , get a ring that is made to run on cast or Nisi and the ring will last alot longer , I run more clearance than .001 per inch of bore on chainsaw cause the engine runs alot hotter than most engines do so this means the piston will gain diameter from the heat faster than the cast sleeve and it will seize , race motors are .002 per inch or in some cases abit more than that , If you get to big on clearance you will have piston skirt crack/break on intake side

joe_indi

Eph,
Thank you for the valuable suggestion.
At present I am using the rings that come with the piston.They are a bit softer than the OE ones.
I did try a set of chromed rings to reduce ring wear. But the CI sleeve wore out instead of the rings.
I tried those chromed rings in a chromed cylinder also. Ruined that cylinder in a week.
The present rings wear well and last more than a year @ 6 hours for 100 days.And they cost only a dollar or less.So, would they not be the ideal one for the time being till I get the sleeves as perfected as possible.
Joe

Jiles

Quote from: ladylake on June 07, 2014, 02:22:55 PM
http://www.smallenginepartswarehouse.com/p/parts-lookup#/Echo_%2f%2f_Shindaiwa/CS-520__S%2f%2fN%3a_C09312001001_-_C09312999999/Engine%2c_Short_Block_--_SB1080%2c_Engine_Cover/8771/8773


Try this link.   Steve

I contacted them with this request---
I am in need of an Echo CS510 Chainsaw Cylinder and possibly a piston.
I understand that the Echo CS510--CS520---and CS530 all carry the same cylinder and piston.
I searched your site but came up with MANY results.
Can you give me your part number?

This was their reply---
I do not stock the parts in request so what you will have to do is purchase from your local Echo dealer.

I can only assume that Echo had a problem with these saws?
That's why this topic is of interest to me--might fix their problem myself??
Satisfy needs before desires

ladylake


I've never talked to them on the phone but have ordered many times with no problems.  Just add your parts to the cart and pay with a credit card, no idea why your having trouble.  When tuned right  those saws are bullet proof , most burn up from being tuned lean with the limiter cap tabs still in place.  No only does that lean tuning burn them up it makes them doggy, tuned right with a muff modd they really cut.    Steve
Timberking B20  18000  hours +  Case75xt grapple + forks+8" snow bucket + dirt bucket   770 Oliver   Lots(too many) of chainsaws, Like the Echo saws and the Stihl and Husky     W5  Case loader   1  trailers  Wright sharpener     Suffolk  setter Volvo MCT125c skid loader

ehp

Joe if your getting a year out of your rings that is perfect , One thing if you can keep an eye on also is your pistons and where they are made , all pistons are not made out of the same stuff and this makes the piston clearanes different again, a Mahle piston on average will run a tighter clearance than a after market piston cause the after market piston does not have as much silicon in it so it gains more in diameter in the heat , On a chrome bore its not so important but on a cast bore its very important

joe_indi

ehp,
Thank you for the valuable info.
jOE

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