squish bands

[tree monkey]

the 026 I did was more like 75-80%, ran real well

 

[huskihl]

Lately, I've been seeing a lot of squish bands cut at way over the old rule of thumb 50% of cross sectional area of bore on saws..
Not sure it's good or bad, just an observation..

I'm sure there's a point of diminishing returns. Combustion chamber must need to be a certain size

 

[Hedgerow]

the 026 I did was more like 75-80%, ran real well

That's a lot..
And I'll bet some of the 7900's lately have been pretty close to that also..
I wonder how much is too much..??
Of course I'm not willing to do the work it takes to find out.
Lol..
And I think I have a case of filers elbow..
Is that even possible???

 

[Windthrown]

Saws ain't bikes........

Sorry........not much at all crosses over from that world into this one.

What about bike saws? That guy in New Mexico on AS of old was into them. They are also both air cooled, which puts them into the same world of which oil to use. Well, unless you swear by TCW in all your 2-smokes.

 

[Brush Ape]

I think he likes me

If you mean me, TM yup I like you. You took Crabtree back to Old School. What's not to like.

 

[drf256]

These are my 026/260 bands. Wayyyyy over 50%. Note the difference in the chambers.

026 Red Lever Mahle


026 KS



MS260




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[Brush Ape]

I think the community would hope you don't rush to judgement on anyone and get to know the person a little.
In this case I have observed a much different person than on AS with an incredible amount of knowledge.

BA is a good dude in my book, never did wrong by me.

Thanks, Gentlemen. Actually I'm just a good bullshitter.

 

[Brush Ape]

Wow, I have only been on this site for 10 minutes and I already have someone to add to my ignore file.

Piltz said he got your new leather pillowcases so you wouldn't chew hole in these like the last ones...??

 

[bwalker]

Lately, I've been seeing a lot of squish bands cut at way over the old rule of thumb 50% of cross sectional area of bore on saws..
Not sure it's good or bad, just an observation..

I have noticed that too

 

[bwalker]

These are my 026/260 bands. Wayyyyy over 50%. Note the difference in the chambers.

026 Red Lever Mahle

View attachment 5235
026 KS

View attachment 5237

MS260

View attachment 5236


Sent from my iPad using Tapatalk

Nice work!

 

[mdavlee]

That's a lot..
And I'll bet some of the 7900's lately have been pretty close to that also..
I wonder how much is too much..??
Of course I'm not willing to do the work it takes to find out.
Lol..
And I think I have a case of filers elbow..
Is that even possible???

The 7900 is that from the factory.

 

[Mastermind]

I use a flexible sanding mandrel to knock the edge off where the band meets the chamber. I'm sure it probably ends up with a little taper near that edge. I'm of the belief that as long as you don't have a reverse taper, nothing is gonna get trapped by the cylinder wall. Most engines I do end up with less than a .300" wide band.......but there are exceptions. On those that are wider, a slight taper might be beneficial.

 

[Miller Mod Saws]

I use a flexible sanding mandrel to knock the edge off where the band meets the chamber. I'm sure it probably ends up with a little taper near that edge. I'm of the belief that as long as you don't have a reverse taper, nothing is gonna get trapped by the cylinder wall. Most engines I do end up with less than a .300" wide band.......but there are exceptions. On those that are wider, a slight taper might be beneficial.

Morning Randy!

 

[mdavlee]

I cut mine on an angle and sand the outer edge flat. The outer flat ends up about the same as it was stock a lot of times.

 

[Mastermind]

Morning Randy!

Mornin Carl.

 

[tlandrum]

this one has a funny looking combustion chamber lol

 

[tlandrum]

better view of the flat squish band and torrodial chamber

 

[tickbitintn]

372?

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[tlandrum]

372?

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yes that was an alchohol saw I built foe les out in mo ,he went by logging 22

 

[bwalker]

I use a flexible sanding mandrel to knock the edge off where the band meets the chamber. I'm sure it probably ends up with a little taper near that edge. I'm of the belief that as long as you don't have a reverse taper, nothing is gonna get trapped by the cylinder wall. Most engines I do end up with less than a .300" wide band.......but there are exceptions. On those that are wider, a slight taper might be beneficial.

Mixture will indeed get trapped in the squish if it's designed poorly. It's actually a pretty big source of unburnt HC emmissions in four cycles as the mixture in that area often doesn't combust.