026 cylinder question/build

[huskihl]

Managed to cut .055 out of the band of the AM cylinder without messing it up, not a big deal for the porters but I'm pretty happy about it.

View attachment 312314

Baby steps……



Lol

 

[Ronie]

Baby steps……



Lol

Is it safe to cut the Meteor piston flat or should I use a 246 piston?

 

[huskihl]

Is it safe to cut the Meteor piston flat or should I use a 246 piston?

Should be able to cut it flat.

 

[Ronie]

Should be able to cut it flat.

Thank you

 

[drf256]

Is it safe to cut the Meteor piston flat or should I use a 246 piston?

You will have to do extra work for a 246 piston and the base gets really thin.

When you cut the dome off the meteor, leave a bit on the edge still on the piston crown. Just enough where you can see it’s rounded and not sharp at the edge.

IIRC, it’s around .045-050 off the crown. I do remember it’s around .005 less for eom slugs than meteor. The center thickness of the crown will be reduced to around .008-.010 thick at its thinnest point, but it will hold up just fine. I’ve probably done over 30 of them at this point with no issues whatsoever.

I’ll be porting and selling some 1121 this coming fall and winter with the same mods. The 246 slug is really only good for all out race stuff. It allows for fingers and a much larger and wider exhaust port and the central single ring pin helps a lot. The pin bosses under the piston need to be relived to fit onto the conn rod of the 1121.

 

[Ronie]

You will have to do extra work for a 246 piston and the base gets really thin.

When you cut the dome off the meteor, leave a bit on the edge still on the piston crown. Just enough where you can see it’s rounded and not sharp at the edge.

IIRC, it’s around .045-050 off the crown. I do remember it’s around .005 less for eom slugs than meteor. The center thickness of the crown will be reduced to around .008-.010 thick at its thinnest point, but it will hold up just fine. I’ve probably done over 30 of them at this point with no issues whatsoever.

I’ll be porting and selling some 1121 this coming fall and winter with the same mods. The 246 slug is really only good for all out race stuff. It allows for fingers and a much larger and wider exhaust port and the central single ring pin helps a lot. The pin bosses under the piston need to be relived to fit onto the conn rod of the 1121.

Thanks, I was wondering how thin the top would get.

 

[Ronie]

I cut the top of a Meteor piston today, the one that came with the cylinder is only .087 on the edge and I felt that it would be to thin once I cut it to support the ring. I could have cut .002-.003 more off the Meteor and taken it to the edge but I figured that little bit isn't going to make a difference.

 

[Ronie]

I put build in the title and I'll post here how this after market cylinder does.

 

[Ronie]

I took a little more out of the band this afternoon and got my squish set, .019-.021, I'm a little off front to back but I'm going to leave it like that, don't want to push my luck. I did get the exhaust way down to 103 or 4 taken by eye.

 

[drf256]

I cut the top of a Meteor piston today, the one that came with the cylinder is only .087 on the edge and I felt that it would be to thin once I cut it to support the ring. I could have cut .002-.003 more off the Meteor and taken it the edge but I figured that little bit isn't going to make a difference.

View attachment 312412

I take a bit more than that. Should work fine though.

 

[Maintenance Chief]

I take a bit more than that. Should work fine though.

What about the spark plug threads ? When taking it farther, any danger there?

 

[Ronie]

Got on the exhaust this afternoon, I've got to mark it out on the piston and If there's enough room I'll put more of a bevel on it. I should have time tomorrow to finish it up.

 

[Ronie]

Finished the cylinder up this morning, I put a larger bevel around the exhaust port and got the timing numbers with a ring. Now I'm waiting on seals and then I can see how it does.

 

[Maintenance Chief]

Finished the cylinder up this morning, I put a larger bevel around the exhaust port and got the timing numbers with a ring. Now I'm waiting on seals and then I can see how it does.

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Those upper transfers are beautiful.

 

[Ronie]

Those upper transfers are beautiful.

Thanks, they don't look as shiny in real life.

 

[Ronie]

I've been on the fence about what to do with the lowers and decided to just take the lip off and smooth them out.

 

[tickbitintn]

That should be a good runner. If I remember correctly you can run into spark plug "interference" after heavily machining base and squish if the plug is not "indexed." I do not remember if that was on an AM or OEM jug though.

 

[Ronie]

That should be a good runner. If I remember correctly you can run into spark plug "interference" after heavily machining base and squish if the plug is not "indexed." I do not remember if that was on an AM or OEM jug though.

I'll check before and see how much space I have before I put it on, thanks.

 

[drf256]

Never seen in an 026, or any Stihl FWIW. Happens w Huskies, the plug angle is different.

 

[hseII]

Cool. You should be able to drop that cylinder a mile. Try and get that exhaust to 100*+. 026 doesn’t mind lots of compression.

Do you even know how much a mile is?

It’s like 100/62 of a Kilomike mike.


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