stihl 066 porting

[Canadian farm boy]

Run the piston to exact TDC mark the piston at the bottom of the exhaust port.(I use a scribe) then when you pull the jug you can measure from the line you scribed to the bottom of the piston skirt, and that is the max amount you will be able to drop the jug without free porting

So basically it all depends on the finished location and shape of the exhaust port. It's mostly about maintaining piston stability and not allowing Freeport. Makes sense now. Thanks.

I guess if you end up with to much compression you can adjust it with your base gasket thickness, right?

 

[drf256]

Front to back dimension is to deep?

Same size without the ramp leading up to the opening?

Front to back too deep for the little mufflers. Width fine.

 

[drf256]

So basically it all depends on the finished location and shape of the exhaust port. It's mostly about maintaining piston stability and not allowing Freeport. Makes sense now. Thanks.

I guess if you end up with to much compression you can adjust it with your base gasket thickness, right?

Also, kinda sorta.

Squish has a few functions. You don' really burn the charge in the squish area during the power producing part of the charge, so any lost volume there reduces power. Also, squish velocity decreases detonation and increases swirl, both of which are achieved better with a tighter squish.

So it's really not a good plan to use squish as your compression variable. Your better off with a larger chamber and a tighter squish.

 

[jmssaws]

Squish at 020 and if you want to loose compression raise the exhaust or open the chamber.

 

[jmssaws]

I degree em all first. Too many variances...

Exhaust has to come down and the intake has to come up on a 660 so I don't bother anymore.

 

[wigglesworth]

Exhaust has to come down and the intake has to come up on a 660 so I don't bother anymore.

Don't disagree there.


But what's the lowest 66 cylinder you've seen?

I've seen a stock at 99.5 before...

 

[jmssaws]

Don't disagree there.


But what's the lowest 66 cylinder you've seen?

I've seen a stock at 99.5 before...

Best I've ever seen was a new 660 cylinder I was 97 120 78, I've seen several at 97 but 120 78 was the best I've seen.

 

[Redfin]

Don't disagree there.


But what's the lowest 66 cylinder you've seen?

I've seen a stock at 99.5 before...

Do you remember trans and int?

 

[jmssaws]

I have to red light cylinders and there 97 123 80. Best exhaust I've seen is 97

 

[Deets066]

Mine was 96 127 80
Stock

 

[wigglesworth]

Best I've ever seen was a new 660 cylinder I was 97 120 78, I've seen several at 97 but 120 78 was the best I've seen.

Was that the best runner?

 

[jmssaws]

Was that the best runner?

That one

 

[Red97]

@drf255





Forgot this one.

 

[Definitive Dave]

gimme, gimme

 

[jmssaws]

The middle size is perfect for the midsized saw.

I'm getting a list together for a order @Red97

 

[Red97]

The middle size is perfect for the midsized saw.

I'm getting a list together for a order @Red97

That was what I was thinking small, 30-50cc medium, 60-80cc and large 80+cc.

Whenever you are ready.

 

[Keith Gandy]

Lemme help here, I know a guy who makes killer deflectors, and I know a few guys that can TIG weld them pretty good tooView attachment 13632 View attachment 13628View attachment 13630View attachment 13631

One of Reds I put on my hybrid today

 

[wigglesworth]

Do you remember trans and int?

I'll have to look. I have it written down somewhere.

I kept that saw stock. It beat Several of the saws at the 066 build off we had several years back...

 

[Moparmyway]

That was what I was thinking small, 30-50cc medium, 60-80cc and large 80+cc.

Whenever you are ready.

I'll take 10 mediums please
I'll just add it to whats heading your way today, with a little extra for beer for ya !

 

[huskihl]

I'll take 10 mediums please
I'll just add it to whats heading your way today, with a little extra for beer for ya !

10 mediums...you going for an orbital style? The ol' 5 port muffler mod?