Stihl 024 build

[farminkarman]

A while back, i picked up this 024 from a member here on the forum.

 

[farminkarman]

The saw didn’t run, but would start on prime. After pulling the carb, I found the pump diaphragm was missing the check valve flaps.

 

[farminkarman]

After ordering new carb kit I decided to pull the jug and see how things looked. The p&c looked great, so I figured I might as well do some hackery on the saw.

 

[farminkarman]

First, I checked squish which came in at 0.034” with gasket. Timing numbers were 100, 129, 67. I started by cutting the dome off the piston, and then I took 0.050” out of the band and 0.045” from the base to get 0.019” squish.

 

[farminkarman]

I decided to shoot for EX: 105, TR: 123, IN: 75. I will post up some pics of the port work when I get that done.

 

[drf256]

Nice Job Greg. I’ve never done a standard 024. I’m assuming it has the WT55 carb?

If you need a metal AF for it, let me know.

 

[farminkarman]

Nice Job Greg. I’ve never done a standard 024. I’m assuming it has the WT55 carb?

If you need a metal AF for it, let me know.

Thanks Al! This one has a WT22 on it…I thought it was supposed to have a Tillotson carb on it, so maybe this was a replacement at some point.

 

[drf256]

Not sure on the 22 vs 55. The 194 has the biggest bore. The China knockoffs are slightly smaller than the 194, but bigger than the 55.

I tried to bore out a 55. No worky, a few circuits right under the bore.

 

[Al Smith]

I didn't see it myself but some have mentioned a pair of 024's at a GTG .Those things ran at over 20,000 RPM's.What had been done them I never heard but they didn't fly apart like a dollar watch .In stock form for only 42 cc's they do okay for light work but they aren't oak slayers .

 

[farminkarman]

I didn't see it myself but some have mentioned a pair of 024's at a GTG .Those things ran at over 20,000 RPM's.What had been done them I never heard but they didn't fly apart like a dollar watch .In stock form for only 42 cc's they do okay for light work but they aren't oak slayers .

I have heard they can scream. I am hoping to give this some more useable power by lowering the exhaust and shortening the blowdown a bunch.

 

[Al Smith]

To tell the truth I was actually looking for an 026 when mine came along for $50 from a dealer .I toyed with the idea of modifying it but only gutted the muffler ,which did improve it some what .I do have a couple of other 3 cube saws that do a better job but this little guy gets used a lot .

 

[82f100swb]

Hmm, open port cylinder wood boss. Does it have the crank with the open rollers and oddball rod that looks like a 170 rod? If it does, I definitely wouldn't be wanting to push the rpm too high. I understand they built the wood boss to be a cheaper saw, but that crank may have been a bit overboard.

 

[farminkarman]

Here is the jug after widening the intake & exhaust, and raising the transfers. I left the transfer roof flat on the exhaust side and tried to leave an upward angle on the intake side of the transfer roof.

 

[farminkarman]

And here is what happens when you use a piston stop to re-tighten the flywheel nut on a domed piston that was cut flat.

 

[farminkarman]

So, now I wait for a replacement meteor to come. I think I might leave the center portion of the piston uncut this time to leave more material…kinda hate pop ups, but not sure what else to do.

 

[cus_deluxe]

And here is what happens when you use a piston stop to re-tighten the flywheel nut on a domed piston that was cut flat. View attachment 383663

#grubbyoldpieceofstringftfw

 

[Duane(Pa)]

So, now I wait for a replacement meteor to come. I think I might leave the center portion of the piston uncut this time to leave more material…kinda hate pop ups, but not sure what else to do.

I would try to measure the Meteor and see if it might have more material in that area. If it does, then maybe give it a go?

 

[farminkarman]

I would try to measure the Meteor and see if it might have more material in that area. If it does, then maybe give it a go?

I think the flat top would have been fine in run, but using the piston stop was a bad idea. I will measure the meteor anyway.

 

[drf256]

I think the flat top would have been fine in run, but using the piston stop was a bad idea. I will measure the meteor anyway.

It should have, but measure anyhow.

Did you measure this one before it broke?

Meteors seem to be a harder alloy than oem. You can also take a little less off the top of the dome and leave a rolled edge at the crown/skirt interface. Wont do anything bad, just sand the difference from the band. A true .015 squish is safe in these saws.

A meteor 026 piston measures around .008 thick at the center of the crown when I’m done with it. Never had one fail, even at 275 psi of compression.

 

[farminkarman]

It should have, but measure anyhow.

Did you measure this one before it broke?

Meteors seem to be a harder alloy than oem. You can also take a little less off the top of the dome and leave a rolled edge at the crown/skirt interface. Wont do anything bad, just sand the difference from the band. A true .015 squish is safe in these saws.

A meteor 026 piston measures around .008 thick at the center of the crown when I’m done with it. Never had one fail, even at 275 psi of compression.

Yeah, I measured it with a straight edge and my caliper...the middle of the crown was right at .100" thick. Probably would have been fine if I had used some rope as a piston stop instead of a screw-in type.