stihl 056 scored piston/cylinder [update]

wood monger · March 11, 2010, 09:51:41 AM

Just got my old stihl 056 running again yesterday. Was told by stihl dealer I had a scored piston and cylinder,ugh! Took the saw apart and the piston was definitely scored up, but the cylinder looked ok, no discernable scratches or other marks. I ended up buying a new set of rings, from stihl, 22 dollars each, and lightly sanded piston to smooth. I took saw to a local guy who I met through forestry forum, He does small engine repair, and has some test equipment. We did a compression test and the saw had 130 psi of compression. We started the saw and set low high speeds with a tach. Have'nt tried it in logs yet but am cautiously optomistic. I hope she's gonna be ok as I don't want to spend a lot of money on a saw that is so hard to find parts for. I really enjoy this site, have gleaned much knowledge and insite on saws thanks for the great work. Also thanks to you guys for sharing your know-how.

Kevin · March 11, 2010, 05:23:59 PM

Give it a little extra oil in the mix for the first few tanks.

windthrown · March 11, 2010, 05:29:38 PM

130# is on the low side. The rings should seat some, but that is a really low start for a chainsaw. I popped in new rings on one of my 026s and that saw went from 130# to 170# before the rings seated. Also you can get a pair if excellent Caber rings for Stihl saws on Ebay for $12 a pair from a guy in Athens, Greece. You might consider doing a light hone on the cylinder to take out any small scoring in the walls. You should do a compression test when the saw is cold as well, with a good tester. When warm the numbers tend to drop.

My 2 cents worth...

Al_Smith · March 11, 2010, 06:18:45 PM

You have to remember that cylinder isn't truely round any more , it's old . It's going to take a bit to seat the rings .They wear in as they wear old so to speak .

Run it a tad rich for a few tanks then lean-er out and run it like you stole it . :D It will be just fine in time .

windthrown · March 11, 2010, 06:21:31 PM

All the more reason to hone it lightly and take out that out-of-round. Use a solid brake style honer and give it a few spins on the end of a drill, moving it in and out of the cylinder.

Al_Smith · March 11, 2010, 08:28:27 PM

I hate to be the bearer of bad tiddings but you can't use a brake hone to reround a cylinder nor can you reround a plated cylinder for that matter .

I have Lisle precision hone that will reround a cast iron lined cylinder plus the diamond shoes for hard nickle plating .The diamonds though are not for rerounding .

I suppose you could give it a quicky just to rough up the cylinder if you choose to .No matter because given enough time the rings will seat ,hone or no hone . No not though grind away a long time if you do hone because even as hard as the nickle alloy plating is you can go through it .Too late then,just a paper weight after that . :(

windthrown · March 11, 2010, 08:36:01 PM

Well, I have used then to take out the rough parts in a cylinder wall, and I know a ton of people that hone cylinders that exact way, regardless. It may only take the aluminum off the walls from the piston or carbon buildup, or both. It also scuffs the walls so that the rings seat faster (if you cross hatch them right).

Personally I would not bother with a saw that only had 130# with new rings, or wait for it to liven up. I just do not see that happening. Chances are the the cylinder is scored, and in that case it is pretty useless.

Al_Smith · March 11, 2010, 09:10:30 PM

Yes you can remove tramp aluminum and clean up a plated cylinder but you can't make it perfectly round with a brake hone,aint a gonna happen . It doesn't make that much difference any way and a dime will get you a dollar with new rings that old saw runs about as good as it did when it was new after a break in period .

Now I'm going to give you a little example and you can believe it or not . A while back another member on this exact forum shipped me a Stihl 038 Mag with a partly screwed up cylinder and a scuffed piston .I cleaned them up,they were not perfect,ported the saw ,pop up piston the whole nine yards .

It took the best part of one summer to get the rings seated and today that thing has to have right at 200 psi on the cylinder .It just took that long to seat in because of the cylinder wear . It's about the same as pulling over an 066 and it's only 72 cc's .

windthrown · March 11, 2010, 09:28:49 PM

Well, I have rebuilt and ported a lot of engines in my day as well.

If you cross hatch the cylinder walls (different hone), it will seat your rings a lot faster.

Also I seriously doubt that you are gonna get a 130# with new ring saw up to stock ring-seat compression (what, 170#?). I just do not see that happening. Stihl rings are soft in my experience, and tougher iron Cabers would be better. I would not run a low compression saw all summer just to seat the rings either. Wated time and energy. Never mind running a 056 these days anyway, or for that long. The vibration would kill me before the rings were seated.

Al_Smith · March 12, 2010, 04:39:20 AM

Quote from: windthrown on March 11, 2010, 09:28:49 PM
I would not run a low compression saw all summer just to seat the rings either. Wated time and energy. Never mind running a 056 these days anyway, or for that long. The vibration would kill me before the rings were seated.

I think perhaps there is a lack of communication here .

Firstly an 056 is in a way kind of old however powerfull it is may be .Of course it isn't a saw one would care to run all day,every day .It is however sort of a restoration project as such and as such it will work .

Now ,low compression being around 160 and jumping to 200 is not what one would consider low compression to start even though the base was indeed altered . I would say running perhaps 15 cord of firewood was time well spent for a 72 cc saw that will cut on a par with a stock 066 . 8)

wood monger · March 12, 2010, 08:43:04 AM

Wow, Al and Windthrown, you guys need to hug and have a cold one. I know this is an old saw but it does have sentimental value. I am however realistic and don't want to spend a lot of money on it. This is not my main cutting instrument, I use a mid size Husky for 90 % of my cutting. I heat with wood and probobly cut 10 to 15 facecords a year. Every now and then I'm able to get a big log because noone else has a big saw or bar to cut them, in this instance, it's nice to have a bigger saw. When this problem arose I checked out several 70ccish saws and they ran 700 to 800 dollars. I just couldn't justify spending that kind of dough on an occasional use saw. I'm leary of buying a used one, and inheriting somone elses problems. Regardless thanks for the input.

Magicman · March 12, 2010, 08:52:17 AM

There is a cylinder, piston, and bearings listed for $75 at CHAINSAWR (on the left).

Al_Smith · March 12, 2010, 08:31:53 PM

Quote from: wood monger on March 12, 2010, 08:43:04 AM
Wow, Al and Windthrown, you guys need to hug and have a cold one. I know this is an old saw but it does have sentimental value. I am however realistic and don't want to spend a lot of money on it.

Yes I know that and I commend you for trying to get it running as best you can .Lord only knows I have spend hours doing the same .

If I came on too strong it was only to point out the fact that irregardless of some ideas things do not have to be perfect when it comes to rebuilding or reviving a saw engine .

Not that it means a hill of beans but I recently spent about a week reviving a 1957 Lombard gear drive to running condition and I doubt I ever use it for more that just demonstration .On the other end of that I have a shed full of fairly fast saws that have had a little bit of enhancement done to them . ;)