low hours Stihl 026 needing Piston & Liner

[Guarddog1]

BCorradi is the guy you want for the piston and cylinder. He has OEM kits for around 85$.(Yep, thats piston and cylinder both) He is a super guy to deal with, and very reputable.

Any way you can pm me the info as well. Thanks

 

[JohnL]

190 psi ???

 

[Brushwacker]

I have an 026 pro top end off. Was very low on compression but run. The piston is about .030 smaller then the new piston from BCorridi and the new piston will not even go into the 026 pro cylinder. No problem, I will replace the pro cylinder with the slightly bigger bore and find a new home for the used pro cylinder. I have 2 of these new larger bore top end assymblies w/o compression release hole + 1 new piston all measure the same , bigger then the pro cylinder bore. All are labled Stihl and Mahle.
Am I missing something? From what I'd been reading on AS. I thought the newer 026's had the bigger bore until now.
Is there any advantages to the smaller bore ?

 

[Bowtie]

I have an 026 pro top end off. Was very low on compression but run. The piston is about .030 smaller then the new piston from BCorridi and the new piston will not even go into the 026 pro cylinder. No problem, I will replace the pro cylinder with the slightly bigger bore and find a new home for the used pro cylinder. I have 2 of these new larger bore top end assymblies w/o compression release hole + 1 new piston all measure the same , bigger then the pro cylinder bore. All are labled Stihl and Mahle.
Am I missing something? From what I'd been reading on AS. I thought the newer 026's had the bigger bore until now.
Is there any advantages to the smaller bore ?

The larger bore is the 260 setup (44.7mm). The smaller setup is the 026 (44mm). The performance difference is slight to none. Some say the larger bore has slightly less power, but that is yet to be proven. If you dont have a use for the smaller setup, I might be able to help you get rid of it.

 

[Brushwacker]

The larger bore is the 260 setup (44.7mm). The smaller setup is the 026 (44mm). The performance difference is slight to none. Some say the larger bore has slightly less power, but that is yet to be proven. If you dont have a use for the smaller setup, I might be able to help you get rid of it.

Thanks , looks like I'll have a couple 026's wearing 260 top ends eventually.

 

[046]

thanks Bowtie... just ordered a P&L from BCorradi... very reasonably priced at $88 shipped via paypal for a no fuss transaction.

I gave ya Brad C's #. Call him and see if he will sell you just a piston. I bet he will, if he has the 44mm piston(026), and not just the 44.7mm (260).

 

[046]

got my new piston & liner set in... but still trying to decide how to port.
shall I enlarge ports sideways or raise/lower ports?

if I enlarge sideways and not change timing... how far sideways?
.5mm or 1mm? don't want to go to large and have rings snag.

another issue that's still unresolved is ... are the big end bearing still in good condition?
will be taking a careful look for damage to edges of bearing cage. Sure don't want to put this together, only to have big end bearing failure.

a bit more detective work analyzing piston failure:

according to this new section at Madsen's I should see scouring on inside piston rod surface, if damage was caused by lack of oil in fuel with bearing surface dry. http://www.madsens1.com/saw piston fail.htm

so far damage on piston indicates overheating, not damage from no oil in fuel.

--------------
small end bearing looks oily and undamaged

inside of piston pin is oily

inside piston side bearing surface show no scouring

other side also shows no scouring

 

[046]

feedback.. anyone?

 

[046]

more detective work, carefully turned bearing 360 degrees... big end rod bearing are oily with zero damage to cages.

it's looking more and more like damage to piston & liner was due to overheating from running too lean. not straight gas. bearings would be dry with cages starting to shred.

 

[046]

finished up the 026 a few minutes ago with new piston and liner...
too late to start her up. can hardly wait until morning...

here's 026 getting vacuum and pressured tested...

new .325 7 pin sprocket and new stihl chain... 026 fin

 

[wigglesworth]

got my new piston & liner set in... but still trying to decide how to port. shall I enlarge ports sideways or raise/lower ports? if I enlarge sideways and not change timing... how far sideways?
.5mm or 1mm? don't want to go to large and have rings snag.

Dont raise or lower, unless you have a degree wheel and some more expertise than most. Widen only unless you are ready to change timing. You need to measure your piston skirt to find out the max width to take your ports, but keep in mind the piston ring ends, as they can be close to the ports. Do a search on "porting". That should keep you busy for a month or two.

 

[046]

started up 026 early this morning.... first had to dump the old gas.

she started right up and felt really good. set the mixture on the fat side to break in a bit. will be checking compression soon.

026 is purring... feels like a brand new saw.

 

[Work Saw Collector]

That saw looks good back together.

 

[MontanaMan]

So did you port the new cylinder it or leave it stock?

 

[046]

decided to leave the new cylinder stock for now.

probably will dig up another 026 piston and do the mods on it first. better to experiment with the old cylinder before moving to new one.

So did you port the new cylinder it or leave it stock?

 

[blsnelling]

What's compression on the new topend?

 

[MontanaMan]

better to experiment with the old cylinder before moving to new one.

Hard to argue with that ...

 

[046]

a crack over 175 on both Snap-on and a new liquid filled gauge.
since there was controversy over if initial readings was correct. took the extra step of verifying accuracy of Snap-on gauge.

What's compression on the new topend?