Fingers and Bridge ports

[Mag Craft]

TIG welded

So no issues with the heat on the plating when welding?

 

[Sty57]

Or peanuts, or bacon.

Or anything picked.....eggs, turkey gizzards, pork hocks......

 

[mdavlee]

So no issues with the heat on the plating when welding?

He may have had it replated.

 

[Jughead]

tig should be good with plating.it works well at not popping cast liners.

 

[huskihl]

Got a date set yet?

 

[Sty57]

Ok so I'm sitting on the couch with a cylinder staring at it.
How would you do a quad port jug with fingers? Like a 372

Or is this something that really benefits a two port jug.

 

[drf256]

Weld in a aluminum bung with a AN fitting Al.

Case is Mag.

 

[Al Smith]

First of all to understand what the porting design does you have to study it .In a nut shell all fingers ,externals even sweeps do is provide a better way to sweep the area above the intake port.Rear or externals are nothing new.Fact The Mc 70 and Mc 100 kart engines came with them Did it work,yes .McCulloch led the kart racing for decades .

Stihl uses rather large single tunnel transfer. Husqvarna on some models use multi tunnel tranfers .The thought on that is just like installing diverters in HVAC main trunk lines,helps the flow ,nothing new .

If you look at the Stihl 020T and MS 200T they have huge open transfers .Which would make sense they have a lower velocity but they preform well .

McCulloch 10 series used semi closed transfers through a windowed piston which actually varied the timing and the velocity of the transfer .On transfer the rear port opened first with higher pressure ,soon after the second port opened with lower pressure and finally the third just about the time the exhaust port was closing .

So with all my ramblings what I'm saying is in order to improve on design you have to know what that design was supposed to do .They might seem the same but they are not .

 

[Mag Craft]

Case is Mag.

Yep case is mag cylinder is aluminum.

 

[Sty57]

Case is Mag.

Drill and tap for NPT

 

[mdavlee]

Ok so I'm sitting on the couch with a cylinder staring at it.
How would you do a quad port jug with fingers? Like a 372

Or is this something that really benefits a two port jug.

You make a hole through the lowers or raise them. There's a few pictures of them on Terry's website.

 

[Ron660]

You make a hole through the lowers or raise them. There's a few pictures of them on Terry's website.

Since the 372 is a quad port, bridges or fingers aren't needed or beneficial?

 

[mdavlee]

They can be if you're going for all out power like a race saw.

 

[SixGun]

Would it make sense to decrease the width and depth of fingers from bottom to top to increase velocity?

 

[Backyard Lumberjack]

This is pretty cool......

We can have a conversation without anyone feeling the need to prove how smart they are.

We are gonna learn how to build some really good saws here.

yep! no doubt in my mind... that is why I followed you over here Mr. MM!

as an fyi - worked all afternoon today on my 044 porting job...and it echos much of the tech and information in one of your how-to's that certainly was interesting, helpful and informative to me... real happy with the results so far, and kept noted boundaries inline per your cautionary guidelines... when I was done with today's work... I was a bit apprehensice... did I get the port too wide by chance and over into the ring gap line? but, happily - no!

room to spare... but not two rooms!! lol...

"let's build some chain saws!!"

 

[Backyard Lumberjack]

It would be very cool to have some kind of Flow Bench to be able to see the changes.

you mean like this? its my SuperFlow SF 1200! spark any ideas of interest perhaps?... in case you are wondering... its a $15,000.00 flow bench... pulls 85 amps on start up... and uses 15 maybe its 18... 220 volt motors to do it's thing... runs both analog and digital systems... can plot and graph before an after mods, its a carb builder's flow bench, top of the line... few yrs back, mint condition...

 

[Sty57]

you mean like this? its my SuperFlow SF 1200! spark any ideas of interest perhaps?... in case you are wondering... its a $15,000.00 flow bench... pulls 85 amps on start up... and uses 15 maybe its 18... 220 volt motors to do it's thing... runs both analog and digital systems... can plot and graph before an after mods, its a carb builder's flow bench, top of the line... few yrs back, mint condition...


View attachment 9832

Yup that's what I was thinking. I have a good friend that has a 4-Wheel and engine dyno, but no flow bench.

 

[Backyard Lumberjack]

Yup that's what I was thinking. I have a good friend that has a 4-Wheel and engine dyno, but no flow bench.

what state? is he looking for a flow bench?.... WI?

 

[Sty57]

Wisconsin
I don't think so, but I will ask him.

 

[leadfarmer]

This is pretty cool......

We can have a conversation without anyone feeling the need to prove how smart they are.

We are gonna learn how to build some really good saws here.

Could we get a two thumbs up button ?