Piston goes which way round?

[tlbranth]

Bought new piston for stihl 034. Does the arrow face forward (toward the exhaust)?

 

[Stihlofadeal64]

Bought new piston for stihl 034. Does the arrow face forward (toward the exhaust)?

Indeed it does. Make sure the rings are oriented on the pin bosses correctly as well. The rings will have a radius on the tips to locate. Wish you well on the install.

 

[tlbranth]

Thanks stihlo.

 

[stevohut]

Another trick you can use if you aren't sure of ring orientation is the locating pins in the ring groove always face the intake side of the motor. Make sure you hone your cylinder to break the glaze from the previous piston and rings. If you don't you will have a hell of a time trying to seat the new rings. You want to use nomore then 500 rpm while honing and a recip motion of about 2 seconds per cycle before switching direction. You want a nice crosshatch pattern on the cylinder wall. Do not use a ball hone they are not as controlable as a 3 arm solid hone. Use some light oil while honing. Then wash the cylinder in hot soapy water to remove any honing grindings. Hope this helps.

steve

 

[tlbranth]

Got that. Probably overhauled 30 engines of one type or another - just not a small 2 stroke. So honing won't go through the plating?
Ordered a ring compressor kit too - from Baileys. It hasan assortment of bands, a red truss-looking thing and a white dogbone looking thing. I've used ring compressors before but nothing like this. Any tips? I'll be cobbling it all together in the morning.

 

[wigglesworth]

Do not hone your cylinder. Do a search for "Hone", and you will see that they dont need it to seat the rings. A saw cylinder is plated, not cast iron, so honing is not necessary.

 

[stevohut]

Do not hone your cylinder. Do a search for "Hone", and you will see that they dont need it to seat the rings. A saw cylinder is plated, not cast iron, so honing is not necessary.

you are wrong doesn't matter if the cylinder is plated if you examine a new set of rings you will see they have their own croshatch patern which needs to be worn in by the crosshatch you apply to the cylinder which will create the proper seal of the rings to the cylinder wall. I am a 2-stroke and small engine mechanic and have been around this stuff for years. I would not recomend this procedure if it was not needed.

 

[stevohut]

One important thing I forgot to mention is when you install the new circlips in the piston pin groove make sure the open end of the clip is in the six oclock position. Reason being there is a potential for the clip to pop out if it is in anyother orientation. It's simple physics. Let me explain, as the piston is forced down on the power stroke you want the inertia to push the circlip to the outside of the clip groove. This happens best at the six oclock position. Say at three oclock if that clip is compressed on the power stroke it now does not fit tightly in the groove because it is compressed onto itself actualy making it smaller then the groove which could cause it to pop out and take out your engine at 13500 rpm that todays pro saws run at. It is rare but can happen so take the time to do it just incase.

steve

 

[wigglesworth]

you are wrong doesn't matter if the cylinder is plated if you examine a new set of rings you will see they have their own croshatch patern which needs to be worn in by the crosshatch you apply to the cylinder which will create the proper seal of the rings to the cylinder wall. I am a 2-stroke and small engine mechanic and have been around this stuff for years. I would not recomend this procedure if it was not needed.

Ok buddy....hone away.

 

[tlbranth]

Thanks for all the input. So does anyone know how this ring compressor set is supposed to work?

 

[stevohut]

Ok buddy....hone away.

pick up a book and do some reading and while your at it go talk to a mechanic and he will tell you the same thing. If he says no he is just as ignorant as you.

 

[wigglesworth]

pick up a book and do some reading and while your at it go talk to a mechanic and he will tell you the same thing. If he says no he is just as ignorant as you.

ROFL.....I have put lots of pistons and rings in saws and never honed one. :monkey:

 

[stevohut]

ROFL.....I have put lots of pistons and rings in saws and never honed one. :monkey:

Well whatever kid, you just keep doing things wrong and you'll be none the wiser. ROFLMAO :censored:

 

[tlbranth]

Jeez Stevo, I thought all Canadians were mellow. eh?

 

[Stihlofadeal64]

Jeez Stevo, I thought all Canadians were mellow. eh?

Evidently not, an over-reaction is sometimes just as bad as a negative reaction. Courtesy and kindness go a long way to evidence a persons professionalism. The honing debate has been hashed out on this forum already, and wiggs made a simple reference to the search feature for
information sake. We're not here to belittle you, just to pass on what
have learned. Have a great day!

 

[stevohut]

Evidently not, an over-reaction is sometimes just as bad as a negative reaction. Courtesy and kindness go a long way to evidence a persons professionalism. The honing debate has been hashed out on this forum already, and wiggs made a simple reference to the search feature for
information sake. We're not here to belittle you, just to pass on what
have learned. Have a great day!

I am pretty mello, it takes a lot to get me fired up. I took it as a disrespect, so I reacted. I thought I was rather civil about it. I just don't like to see people get bad advise that's all. I have a hard time letting things be unjust. I was not aware this topic was debated before. Didn't mean to stir the pot.

steve

 

[a. palmer jr.]

Thanks for all the input. So does anyone know how this ring compressor set is supposed to work?

I hope I don't start another controversy but in my opinion it's probably not needed on most 2 cycle engines. Most of the ones I've installed can be compressed with the fingers and most are just one or two rings and they're not thick like automobile rings are. You also have to be careful to keep the rings aligned with the alignment pins when installing.

 

[Stihlofadeal64]

I hope I don't start another controversy but in my opinion it's probably not needed on most 2 cycle engines. Most of the ones I've installed can be compressed with the fingers and most are just one or two rings and they're not thick like automobile rings are. You also have to be careful to keep the rings aligned with the alignment pins when installing.

Don't think it will be a controversy. On the Stihl 029's/039's and MS290's I never use a ring compressor. I have a method I use with a carb adjust screwdriver. Otherwise on the saws like yours with the magnesium crankcase I use a hose clamp (redneck idea I guess). But I've built scores of saws using it with no problem.

As stated make sure the rings are aligned on the pins before you install the cylinder. You should be fine, happy sawing.

 

[tlbranth]

Well, the one lattice looking piece was to sit the piston on. And the loops, for different size pistons, are just squeezed by hand. The whole thing went together very easily. I made a "hone" with a dowel. Cut a slit in it with a bandsaw and put some 500 grit silicon carbide paper in as a flapper. That's what I've always done on automotive stuff. Took some of the glaze off and the saw runs fine. Back in the 60's I put motorcycle engines back together with no ring compressor. Just thought that for 7 bucks it was worth the peace of mind. Thanks everyone for your help.

 

[Stihlofadeal64]

Well, the one lattice looking piece was to sit the piston on. And the loops, for different size pistons, are just squeezed by hand. The whole thing went together very easily. I made a "hone" with a dowel. Cut a slit in it with a bandsaw and put some 500 grit silicon carbide paper in as a flapper. That's what I've always done on automotive stuff. Took some of the glaze off and the saw runs fine. Back in the 60's I put motorcycle engines back together with no ring compressor. Just thought that for 7 bucks it was worth the peace of mind. Thanks everyone for your help.

Good deal, post a picture of your saw if you can. Glad all is well.