Porting the 046-D Jug

[mdavlee]

The only KS cylinders I seen on 460s were late ones around the time of the stihl branded ones.

If you have less intake and more case pressure you get more velocity. If the transfers are too high you lose velocity and flow is lazy. The same with huge upper transfers.

 

[drf256]

So they must have small tunnels and great case pressure if they like them that high.

The 460 jug had much wider transfers.

So, do pop up jugs, where the uppers arent as wide vertically, flow better? Or does it not matter after the initial opening?

 

[Mastermind]

Al, you asked for an explanation, I'm gonna wager that you have as good an understanding on the "why" as any of us. I can't tell you why these things like different numbers. I'm just not that smart. Luckily for me, I've done a bunch of saws, so I've been able to see what works, and what doesn't.

On the 046, vs 460 jug. Wiggs has mapped dozens of these jugs. It's rare to find two alike, but not uncommon to see a dozen that all have different timing numbers.

Crazy huh?

 

[MustangMike]

As requested, here are the pics of the unported 460 jug:

 

[MustangMike]

And a few more:


Also, Al, Thanks for the Soppressato, had a little with lunch and will have a little more with some wine & cheese later. Great Stuff!

 

[MustangMike]

These are pics of the jug I was led to believe was NG!!! You don't even have to touch it, although you can see casting marks in transfer ports. The D jug was cleaned up much better.

 

[jmssaws]

I've built a few stout 460's cutting the chamber but my personal and strongest I've ran has a popup 064 piston and almost no machine work, it's nice for a customer to be able to change the piston himself but from a performance point of view a popup is just as good and maybe better in some cases especially on saws that you have to raise the exhaust a bunch or the transfers.

 

[mdavlee]

If I remember right that cylinder is one that ran about the best out of 6 I had at one time.

 

[jmssaws]

I've degreed a mountain of cylinders off stihl saws and you would have a hard time finding 2 alike. And people wonder why one new saw will out cut the other.

 

[angelo c]

And a few more:


Also, Al, Thanks for the Soppressato, had a little with lunch and will have a little more with some wine & cheese later. Great Stuff!

at least you managed to pilfer some Soppressato....that made the trip worth it...saws, porting...smaws schporting....life is all about dried pork !!!!

 

[angelo c]

I've degreed a mountain of cylinders off stihl saws and you would have a hard time finding 2 alike. And people wonder why one new saw will out cut the other.

I find it very true in 1128 but not so much in 1122. 1122 I have found to be slightly more consistent but there are many variations within the series.
clear as mudd.

 

[jmssaws]

In the last two weeks I've degreed 8 or 10 66/660 cylinders and everyone was different. Mostly transfer timing.

 

[angelo c]

In the last two weeks I've degreed 8 or 10 66/660 cylinders and everyone was different. Mostly transfer timing.

but they "seem" to run in similar fashion. I've had some 460's that were awesome...and some were just great saws.

 

[drf256]

Now you guys see what I'm talking about.

He's got some phlucking unicorn cylinder. It's like an angle plug 292 small block Chevy head for a Stihl.

I'm the first one to say we can improve on what the factory did, and it's been true in my limited experience, but the jug he has has wider and nicer ports than I can grind.

 

[jmssaws]

I'd like to have a unicorn cylinder.

 

[drf256]

I'd like to have a unicorn cylinder.

I'll send u a few.

They're pink though, with blond fins.

 

[jmssaws]

I'll send u a few.

They're pink though, with blond fins.

That's the only way I want one!

That's some nice port work al,slick grinding impresses me and that's slick. Good job

 

[drf256]

That's the only way I want one!

That's some nice port work al,slick grinding impresses me and that's slick. Good job

That's the factory cylinder. It impressed me too.

 

[jmssaws]

That's the factory cylinder. It impressed me too.

The factory cylinder?

 

[drf256]

The second cylinder pics in this thread. That's factory.