It's Alive! My first project saw ever (034AV), is running at last.

Alternate titles for this post might be "My Long Learning Curve," or, "It Takes A Village To Fix a Saw."

The first project saw I ever acquired as an 034AV, and I got it for free from a fireman in Cleveland. He was at work when I was passing through late last July, so I met him at the fire station and traded a box of donuts for it. It had locked up on him and he didn't think it was worth fixing. I had recently acquired a kit of chainsaw-specific tools from a retiring shop owner, and was anxious to try them out.

The piston and cylinder were badly scored. At first I thought I'd identified a leaking crank seal as the culprit, but it turned out to be a spun bearing that had worn the clutch-side bearing recess in the crankcase quite a bit oversized, making a big air leak.

Suggestions for how to deal with it were divided between getting a used crankcase on the one hand, and trying to fix the original on the other. I took the latter approach, to the detriment of my wallet. After splitting the case with improvised tools, I bought a pair of aftermarket bearings and a tube of Loctite 640. I used a centerpunch to peen a bunch of divots around the damaged crankcase recess in hopes of raising bumps high enough to grab the bearing at least a little bit, but it didn't really work. I tried gluing the bearing in place with the loctite and managed to assemble the crankcase around it too, but the clearances were so large that the loctite, which cures only in the absence of oxygen, never set up. Weeks later, that 640 was still liquid, and a pressure test just blew it all out and reproduced the leak that had killed the saw in the first place. I didn't know what to do then, so I put all the parts in a box (really a couple of boxes) and left it on the garage floor for the rest of the summer, fall and through this winter while I acquired and fixed several saws with much simpler problems.

Early this year I decided to give it another shot and ponied up $82.95 including shipping for a great-looking crankcase on eBay, supposedly complete with crank, good bearings and seals. When it arrived I found it had suffered a catastrophic crankshaft and rod bearing failure.
My original crank was in fine shape, and since I didn't want to have to start looking again for a case in good condition, I asked the seller if I could keep the case with a partial refund instead of returning it for a full refund. The seller appreciatively accepted.

When I split the new case to swap crankshafts and bearings, I discovered to my dismay (as described in another thread here) that the bearing recess on the flywheel side was just a tiny bit loose - nothing like the spun bearing situation in the original case, but still not quite right. So, again with the debate as to whether to give up and part it out, try a third case, or attempt to use this one. Reasoning that the flywheel bearing is subject to less stress than the PTO side, is trapped between a shoulder on the crankshaft on one side and the outside of the case on the other, and was anyhow just a tiny bit looser than it should've been, I again decided to try using the case I already had. Heck, I already had a tube of appropriate Loctite.

I adapted an assembly method that Mastermind described in detail on AS, for putting the crankcase together without force. His thread pointed out that the crank bearings will slide easily onto the crankshaft if they're warm enough. So, I started by installing the room-temperature PTO-side bearing into that side of the case at about 250F, positioned against the oil pump, then let the bearing heat up in the case (had to turn it up to 260F), and slid the crankshaft into that bearing and removed the assembly from the oven to cool.

Then, I popped the flywheel side bearing into its half of the case without Loctite, laid on the case gasket and heated that side up in the oven.

When it got up to temp I just dropped the cold crankshaft into the hot bearing and quickly drove the case screws home, so that the bearing would shrink onto the crankshaft in just the right place.

When it was all cool I removed the case screws and separated the case halves again, which was easy since the flywheel-side bearing was just a slip fit.


I swabbed a bit of the Loctite on the bearing and in the crankcase recess, and reassembled, then put the whole thing back in the off-but-still-warm oven for an hour or so to help speed curing. The next day I took the screws out and knocked the locating pins back so that I could tug on it a bit to confirm that the loctite had grabbed as it should. It worked!

I realigned the case halves and gasket, pushed the alignment pins back to where they belonged, torqued the screws and declared a tentative victory.

From there it has been more or less straightforward. I installed a new Hyway 036 top end, performed the standard pressure and vacuum tests, and built the saw up with a collection of mostly-original parts and a few not-so-originals acquired on eBay, from my local Stihl dealer and through the generosity of a couple of members here. And now, more than 10 months after seeing the Craigslist ad that sent me down this road, I have a running 034AV / 036. There are few little details to iron out, like the fit of the engine shroud and muffler, but it's substantially done. Here it is, looking pretty much like it did the day I got it (but cleaner), with a video of its very first cuts. Woo!




I owe special thanks to Dexter, who provided an impulse line, a starter cord and a lot of encouragement when I first started last summer, and to BuckthornBonnie who more recently donated a clutch and a brake band along with more good wishes. Thanks guys! It seems like longer than 10 months, and I'm amazed how much I've learned along the way.

 

Great indeed. Now the next project will seem like a breeze ! Nice work

 

Nice job Jon.
Way to stick with it, and good on the guys who helped you through it.

 

Great detailed post.

Someone once told me that "cheap stuff ain't good and good stuff ain't cheap". You could easily replace the word cheap with easy on this build.

 

NICE JOB! Excellent post, pics, details, etc. I have the same exact saw (Hyway top end) and it's my go-to. On my new compression tester it blew over 150 after about 10 tanks with AM base gasket (other 034s 140/150... 026 fresh rebuild 170) . If I wanted to I'm sure I could get the compression up by messing with the squish a bit... it's such a good runner I don't know that I need to.
I'm glad you could get the parts to work out for ya. I'm still looking around for an extra 036 muffler and will let ya know if I find one.

 

Really nice job man, that baby is a piece of art! That's the only way to learn, have at it yourself (with some help from your friends) and see it through till the end!

 

Thanks, everyone. I only wish there was space in my stacks so I had an excuse to do some real work with it and see how it performs.

 

Bring it out here any day, we'll give it a real workout out back!

 

Nice job! So how's it run?

 

So you gonna sell it now ;-)

 

Good job and excellent write. Up. If I had more time I would love to split some cases and teach myself this as well. That won't happen anytime soon. I have at least 2 saws that need simple fixes to be sold just have to find the time.

 

Thanks! I didn't expect to see this thread dug up again. I haven't used this saw a whole lot since putting it back together but when I have it has run very well. I've thought about selling it, because I seem to prefer a combo of a small saw and a largish saw rather than a single medium-sized saw, but after all I learned from and put into it, I'm not ready to let go.