026 crankshafts... help!

[andrethegiant70]

Ok, fellers, as usual, when I'm up to my eyeballs in REAL work (now), my mind drifts off to planet chainsaw, a much warmer and happier place than I am actually in. I'm hoping you can help me.

I am starting another 026 project and plan a ground up rebuild... bearings, seals, etc. We have watched Mr Snelling create the 026 Magnum II (Hey, it's gotta have a name, right?) and I'd like to do something similar. Why not, a guy's gotta do stuff, eh?

Here's my problem. I've got a few decent bottom ends to choose from, only I'm not absolutely sure that they are (all) 026s and not 024s. I have one case that is definitely an 024, but the ONLY reason I'm sure it's an 024 is that it has a stamped steel rod, which I believe was only available on the 024. Newer versions of the 024 had a rod that is of the same construction as the 026. I have looked at these things from all angles, sat them next to each other, buggered around with rulers, and the bottom line is that there is so little difference in crank throw that I'm not sure I can tell the difference. I know there are some guys who are going to say to just extend the rod, measure to the top and you're done. But have you ever done it? We're talking one mm here on an assembly that is gimballed in two different places. It's not easy at all!

Is there any easy way? Now I have to go off and do real work, but I'll be back when I'm burnt like a french fry again.

On another note, how come I don't see chestnuts at the store anymore.

 

[Jacob J.]

On another note, how come I don't see chestnuts at the store anymore.

They're in the chest...

Your chances of having the early 024 shorter crank that looks like the modern 026 crank are relatively slim. There were very few of those saws sold in North America. The 024 Wood Boss and Super both have the same crank as the 026. So it's quite likely that if you pick up a case with a modern crank it's going to have correct stroke.

 

[sefh3]

Isn't the stroke different between the two. The cranks I think are the same but the rod is different.

 

[albert]

I'm not positive, but all 024's are not side adjust chain tensioners

 

[stihlavarna]

I'm not positive, but all 024's are not side adjust chain tensioners

I found that out too, when my 024 threw the rod, I put in a 026 bottom end
and the adjusters were different.

also to 026 had taller cooling fins on the head

 

[bcorradi]

I've dealt with a lot more 026's than I have 24's, but to the best of my knowledge.
1) If it has a stamped rod its definately a 24.
2) If it says 1121 on the cast rod its definately an 024 AVS, Super or 026.
3) The chronology of the 024's are AV, Woodboss, AVS, and then Super. The AVS and Super are the ones with the same stroke as the 026.
4) If it has a cast rod with another number besides 1121 it is an 024. I wish I could remember what that number is.
5) If I remember correctly I seen some cast rods that were stamped with a 1121 and had a star above them and these came out of 024 supers.
6) I believe albert is indeed correct and some of the last runs of supers did have side tensioners.

Other small tidbits.
1) They have seemed to do a few funny things during the 24 era and when they were transitioning to the eventual 026. Some of the 24's had single ring pistons and had closed transfers.

2) To my knowledge it was a bit strange when they made the transition from the non super to the super and eventual 026 that they increased the stroke and not the bore. All other model families that changed names and displacement usually just changed the bore. i.e: 034 to 034 super/036, 038 to 038 super to 038 magnum, 056 to 056 super to 056 magnum, etc.

 

[Jacob J.]

Brad- no to question what you're saying, since you're the 026 guru here, but every crank I've pulled out of the 024 Wood Boss saws had the same stroke as the 026, and I've dismantled five of those now. In addition to those I've pulled apart 16 or so other 024s and only one had open ports.

 

[andrethegiant70]

It's past midnight and I'm finally done with work! Again, I say, thank God for chainsaw fun.

You guys are the bomb. If I'm reading all this correctly, if I have 1121 stamped on the crank, I'm in good shape. I owe you fellers some rep, that's for sure. It would be an ugly waste of time to rebuild the wrong bottom end.

I'm on my way, thanks!

 

[volks-man]

andre,
i have been in the same pickle as you lately.
the best way i found was to mic the piston. i understand that if the piston is 44mm you have 026.

short of that, if p/c are missing, i am still in the same pickle as you.

 

[andrethegiant70]

andre,
i have been in the same pickle as you lately.
the best way i found was to mic the piston. i understand that if the piston is 44mm you have 026.

short of that, if p/c are missing, i am still in the same pickle as you.

I know what you're saying, but my big problem is that these cases don't have a piston associated with them. I just have three cases with rods sticking out of them. Non of them have the slot in the bottom for access to the adustable oilers, or I think THAT would be a clue also... I don't think the 024 had the adjustable oiler option.

The problem is that there's no good reference for measuring the crank. If the stroke is 1mm different, then that would be 1/2mm at the bottom of the stroke and 1/2mm at the top. (BTW, a longer rod would just raise the piston, not lengthen the stroke). That is not much to measure without a very good reference. I HAVE contemplated doing a dry assembly of a piston and jug setup and then measuring the squish. Installing a jug would give me the reference I need to measure things up. I just have a feeling I would get a number, be back here, and we'd be goofing around with what number it ought to be. It might work out ok, though. It would just be nice to get started on the bottom end and not wait for a piston to arrive.

 

[volks-man]

andre,
according to the ipls for 024 and 026, 024 super had the same crankshaft as 026, both have # 1121 030 0405. 024 non-super was different from 026.

i know it doesn't help you identify them but it does show that your chances of having a case with the correct stroke may be a little greater.

on the mention of adjustable oilers:
i have a whole pile of 024s and 026s and not a single solitary one has an adjuster hole in the case. some of these cases have 44mm pistons sticking up out of them so i know they are 026.

look at the oiler itself. a plastic non-adjustable pump should be 026 non-pro. though they also had aluminum sometimes too as i recall. maybe that will help.
good luck!

 

[bcorradi]

Brad- no to question what you're saying, since you're the 026 guru here, but every crank I've pulled out of the 024 Wood Boss saws had the same stroke as the 026, and I've dismantled five of those now. In addition to those I've pulled apart 16 or so other 024s and only one had open ports.

You may indeed be right...I guess if it is then only the 024 AV is the only one with the non 026 stroke. The 024 Woodboss, AVS, and super have the correct stroke. Yeah your also right I meant open transfers.

 

[andrethegiant70]

Well, I think we've made excellent progress here today.


There's actually some information here that, as far as I can figure, has not been conjured in years past. At least nothing like it showed in my searches. Thanks for sharing your talents!

 

[bcorradi]

Also this just came to me, 1114 s the prefix on the con rod of the non 026 stroked 024's. 1114 is the prefix for the old 020 bucket saw (predecessor to the 020t).

 

[67 Mustang]

On another note, how come I don't see chestnuts at the store anymore.

No one has any nuts anymore!

 

[andrethegiant70]

Also this just came to me, 1114 s the prefix on the con rod of the non 026 stroked 024's. 1114 is the prefix for the old 020 bucket saw (predecessor to the 020t).

Of course, Brad, the fact that you remember this means that we're going to have to monitor your sanity very closely. :jawdrop:


All three of the cases I have that LOOK like they might be 026s indeed have the 1121 cranks, so I think I've got some good choices. Like Volks-man, I do wish one of them had the slot for the adjustable oiler. Not a big deal, though, the non-adjustables seem to do a nice job, if not overly so.

 

[bcorradi]

I don't know if you like the adjustableness of the adj oilers or just that it doesn't oil at idle. I have never drilled an older non adj case to allow you to adjust the oiler. However if your just like the feauture of not having it oil at idle you could just install an adj oiler set to max and not even alter the case. If you need any adj. oilers I have a few new ones I could sell you reasonable.

 

[volks-man]

Also this just came to me, 1114 s the prefix on the con rod of the non 026 stroked 024's. 1114 is the prefix for the old 020 bucket saw (predecessor to the 020t).

are you saying that an 024 'shorter stroked' case will always have 1114 on the conrod?
is this the most fool-proof way to tell 024 stroked case from 026 case?

i sure hope the answer is in the affirmative..... these dang cases are driving me nuts as well.

thanks to bcorradi and jacob j.!