Stihl 029 rebuild- piston ring compression problem!

[Robin W]

I bought an aftermarket rebuild kit for my Stihl 029- the old piston and cylinder head were both very scored. By jeepers one has to pull a lot of the chainsaw apart to get to the nitty-gritty! The Stihl 029 has a split crankcase which means that the piston is a fair way up the cylinder head before the rings get to meet the inside of the cylinder. This means that there's no room for a 'standard' ring compressor to hold the rings in place as you introduce the piston into the head. With the rings in place I stupidly gave the head a light tap with a mallet and I now have a broken piston ring. Anyone have any good ideas how to get the piston into the head with the rings intact?

 

[smokey7]

Yes use a tongue depresser to gently poke rings into the piston or with a awl. I have used the zip tie method too with success. Definitely don't hit it with a hammer.

 

[Robin W]

Zip-tie sounds like a good option- will definitely give this a go... after I've purchased another piston ring!

 

[smokey7]

Very good. Check over the entry point of the jug and be sure it's a smooth entry with no burs. Line up the ends of the zip ties into the transfer ports. I usually try and have the top edge of the ring exposed so it starts in the jug gently push in and clip the tie off, them her next ring in if it has two. You will see what I mean good luck. Oh and cut wood when you are done please.

 

[Robin W]

Thanks very much for your advice... once I have the new piston ring/s I'll let you know how I went.

 

[smokey7]

No problem happy to help. You still may need a tongue depresser depending on tenique.

 

[a. palmer jr.]

I usually just push the piston in until the ring gets to the stop and gently push it in with a small screwdriver. I've never had a problem with this technique. BTW on an 025 you don't need anything, just push the piston in and the ribs of the cylinder work as a compressor. I can't believe they can't do this on an 029.

 

[hotshot]

I think this 1127 893 2600 or 2602 tool is the one made for the 029-039 series, you can also look in the service manual to tell.
Pretty cheap at your Stihl dealers.

 

[a. palmer jr.]

That tool might make it faster but I've done several this summer without a problem but you do have to be careful..

 

[Full Chisel]

I just use my fingers to compress the ring in the groove and work the cylinder on with the other hand. Pretty simple when you get the hang of it.

 

[Full Chisel]

And I would go with a Caber or OEM ring since you broke the crappy Chinese one. And hope for the best when you run it in a cylinder of questionable quality. Good luck.

 

[ssm1699]

My new P&C went together without having to compress the rings. Everything slid right in without any real pressure. At least on my AM cylinder and on my OEM 029 Super cylinder, there is a taper in the base of the cylinder for putting the piston and rings in. My saw is running great too.

 

[a. palmer jr.]

My new P&C went together without having to compress the rings. Everything slid right in without any real pressure. At least on my AM cylinder and on my OEM 029 Super cylinder, there is a taper in the base of the cylinder for putting the piston and rings in. My saw is running great too.

Yeah, that's the idea but I seldom get it to work that way. Seems the rings catch right at the top of the taper. I guess it might help to oil the tapered part slightly..

 

[ssm1699]

Yeah, that's the idea but I seldom get it to work that way. Seems the rings catch right at the top of the taper. I guess it might help to oil the tapered part slightly..

When I did mine, I oiled everything pretty generously. Just used stihl regular 2 stroke oil. Put it on my finger and coated every surface that the piston and rings touched. Had enough on the taper and cylinder walls that it was dribbling out of the spark plug hole. I just carefully put the piston at the start and just slowly rocked it back and forth, til it dropped fully into the cylinder. Worked like a dream. I even bought the ring compressor and never used it.

 

[ssm1699]

I wouldn't mind coming up with another 1127 series PHO, that needs the top end rebuilt. My cylinder and piston really were in better shape then I had thought, when I decided to do the rebuild. So was thinking I could get another that the top end is completely trashed and rebuild it with my oem P&C and just put new rings on the piston. I would be cleaning up the cylinder before assembly. But haven't had the money here lately. More important things that need to be taken care of first.

 

[a. palmer jr.]

I'm always on the lookout for a 290 that needs rebuilt. Around here nobody wants to rebuild them so I thought why not me? I know how and have a little spare time..

 

[ssm1699]

My wanting another is just to have another saw of the range and put one of my b&c on it, after rebuild.