advice on rebuilding a engine please

[burrell_]

i need some advise i have a old 024 witch iv cleaned the bore up what i wont to no is.

the old piston had only 1 piston ring on it but every piston set i can buy has 2 pistion rings on them would this make a difference or do i need to spend a bit of time on my lathe turning up a new piston with one ring on it

 

i cant see where the extra ring would make a difference/ be a problem but thought i would ask and see what what feed back i could get

cheer martin

[Tree Man Tom]

Be fine with 2 rings mate.

[burrell_]

thats what i thought but i thought i would ask

[spudulike]

Strange the Stihl has a single ring piston - it may be a non OEM one, does it have "Mahle" on the inside as they manufacture most of the OEM pistons for Stihl, Jonsered and Husqvarna?

 

I have looked at the IPL and it has a two ring piston as standard!

 

How did you clean the bore, the aluminium cylinder has a chrome or Nikasil plated bore so honing as per a four stroke engine is a big no no!

 

I would fit the two ring piston, ensure the location pins run where there is no port and solid cylinder wall. Apart from that the job should be a good one - the arrow on the piston crown points to the exhaust port!

 

Spud

[tommer9]

There should be 2 rings in that saw.

[Pat Ferrett]

I was told buy an old boy that rebuilt engines to always run a file lightly around the top corner of the ring, if the cylinder had'nt been honed so it didnt travel up and srike the lip worn away by the previous ring at DTC.

[burrell_]

i can tell u the piston in the saw is what was in it when it was new as dad brought the saw new and has never replaced anything i thoguth it was strange as all the info iv found is with 2 rings in this saw

[TimberCutterDartmoor]

There should be 2 rings in that saw.

 

Ditto

[spudulike]

That piston looks like it may have transfered aluminium on to the cylinder. Be sure to get rid of this as it will cause some damage to the new piston.

 

Back to my original question - is the piston manufactured by "Mahle"? it will have the name moulded in to the underside of the piston!

 

Single rings will have less drag and produce more power but transfer less heat and not have as high compression when the ring wears.

 

The saws IPL states two rings - this is mighty strange - will ask the fellas over the pond for an opinion!

 

Spud

[spudulike]

The reply from accross the water: -

 

"The 024 came with four different pistons, two of which were single ring. One was a full-circle piston like the Husky 266, one was a narrow-skirt piston like the modern 260. "

 

Now we all know

 

Spud