Chainsaw Porting Theory

[Stihlbro]

Did you widen the ports any?

 

[Al Smith]

I mostly do 660's and after a couple hundred of them you get faster at it.

Now exactly how does one get ones hot little hands on literally "hundreds of Stihl 066 or 660's" to preform magic on ?I would speculate that less than 3 percent of all chainsaws owners in the entire world have enhanced saws . Fess up now.

 

[Stihlbro]

I hear you Al Smith.

 

[drf256]

Did you widen the ports any?

Yes. Squared and widened intake. Widened exhaust.

The uppers are not widened at all. I took care to specifically not widen them past the factory opening in the plate.

No bridges or fingers. Pics are before final chamfers.

 

[drf256]

Now exactly how does one get ones hot little hands on literally "hundreds of Stihl 066 or 660's" to preform magic on ?I would speculate that less than 3 percent of all chainsaws owners in the entire world have enhanced saws . Fess up now.

Jason ports for a living, for many years. He lives in 066 country, says that's all most use by him for pruning rose bushes to stumping.

So he ports 066's all day, everyday. He does a lot of things that may be contrary to theory because he knows they work through experience.

Pretty much the foremost 066 expert IMHO.

 

[XP_Slinger]

On increasing transfer exit pressure. Filling areas with JB would certainly do it, but there is a balance to maintain. As stated way back in this thread, if your transfer charge enters at too high a pressure you blow more of the fresh charge out the exhaust. This is where entry angles can optimize entry at lower pressures. In my head, I want to fill the cylinder from the bottom up to lift the exhaust up and out. Would be even better if one could stagger transfer opening, 1st opens flat, 2nd opens angled slightly up and toward the intake. I would think the goal in any configuration would be to avoid turbulence that would encourage exhaust and transfer charge mixing. Most of this would be found at the piston when the transfer opens.

 

[Moparmyway]

I think it plays a big role actually.

Also likely the reason that some models do better with popup Pistons.

I'll be seeing how this one works soon

 

[Deets066]

Jason ports for a living, for many years. He lives in 066 country, says that's all most use by him for pruning rose bushes to stumping.

So he ports 066's all day, everyday. He does a lot of things that may be contrary to theory because he knows they work through experience.

Pretty much the foremost 066 expert IMHO.

He ports a LOT of 66's for people in his area. He also is buying 66's at least once a month! I think that's the only saw people use in that county lol

 

[drf256]

On increasing transfer exit pressure. Filling areas with JB would certainly do it, but there is a balance to maintain. As stated way back in this thread, if your transfer charge enters at too high a pressure you blow more of the fresh charge out the exhaust. This is where entry angles can optimize entry at lower pressures. In my head, I want to fill the cylinder from the bottom up to lift the exhaust up and out. Would be even better if one could stagger transfer opening, 1st opens flat, 2nd opens angled slightly up and toward the intake. I would think the goal in any configuration would be to avoid turbulence that would encourage exhaust and transfer charge mixing. Most of this would be found at the piston when the transfer opens.

Excellent posting.

That's what the factory created with quads. Smaller tighter transfers, but more of them. So velocity and flow at the same time.

They also open as you say. Flat across the piston first, then upwards.

 

[drf256]

I'll be seeing how this one works soonView attachment 14909

Certainly may be a winner Mopar. Less playing with what the factory gave you.

I guess it really depends saw to saw. If you've got crappy transfers with not enough area or bad entry, a squish cur will give you more leeway for change. If you've got a good looking setup, I see an advantage to plying with them less.

I've heard Snelling's 044/46 hybrid runs insanely well with a popup. Some say better than a band cut saw.

I've wondered if this is because he's got that tight case and is able to keep the transfers smaller because he's not raising them as much and a band cut saw.

There has to be something to it in certain saws.

 

[Moparmyway]

Certainly may be a winner Mopar.
Less playing with what the factory gave you.
There has to be something to it in certain saws.

less is more ( sometimes )
And ................ I have a NOS 661 piston, just sitting in a box

 

[jmssaws]

Now exactly how does one get ones hot little hands on literally "hundreds of Stihl 066 or 660's" to preform magic on ?I would speculate that less than 3 percent of all chainsaws owners in the entire world have enhanced saws . Fess up now.

I probably have over 20 660's maybe a dozen runners.

I'm in logging country and know at least 20 loggers personally,how many saws do you think a logger will use over a 20 year period? How many saws do you think I've ported in the last 10 years alone?

As far as the other guys crank stuffer question,I have no idea.

Just because my name isn't randy and I haven't been on a forum for 10 years doesn't mean I haven't ported a bunch of saws.

 

[Deets066]

I probably have over 20 660's maybe a dozen runners.

I'm in logging country and know at least 20 loggers personally,how many saws do you think a logger will use over a 20 year period? How many saws do you think I've ported in the last 10 years alone?

As far as the other guys crank stuffer question,I have no idea.

Just because my name isn't randy and I haven't been on a forum for 10 years doesn't mean I haven't ported a bunch of saws.

Horn tooter

 

[XP_Slinger]

Now exactly how does one get ones hot little hands on literally "hundreds of Stihl 066 or 660's" to preform magic on ?I would speculate that less than 3 percent of all chainsaws owners in the entire world have enhanced saws . Fess up now.

I don't think questioning the credibility of a builder who is generously sharing information with all of us is an intelligent choice of tact with regard to encouraging further relevant discussion. Lets keep this thread going in a productive direction.

 

[jmssaws]

A small amount of respect goes a long way.

 

[jmssaws]

Horn tooter

Toot toot!

 

[Redfin]

Horn tooter

All I read was azz smasher.

 

[Stihlbro]

Drf255, nice looking work as usual. In my experience, once you have ported the saw and run it, then you can decide if you want to make changes. One thing for certain, the way you like how a saw performs can be different from others. Main thing is you are happy with it.

Jms, it's quite obvious from following your post that you mainly do 1122 series saw. You've stated you've done hundreds. Or better yet thousands. That great! You are no different from anyone else here and had to start some where. No disrespect from my end. Just remember anything you post, you can be called out on. It's the Internet.

Carry on.

 

[jmssaws]

1000's? I said I've had a 1000 apart.
I mostly do repair work,porting has slowed down alot.

Randy has ported a 1000 or more not me.

 

[Sty57]

One thing nobody seems to talk about. Do any of you do anything to the pistons?
" Lightning, Cleaning up the Casting flash or just Relieving the Corners"
I would think a lighter piston would be better without going overboard.