Echo 7310 build thread

[GoBigBlue1984]

Will you be doing 3 separate transfer times, or just a primary and secondary time?

Right now the plan is to run 2 separate transfer times. Open the secondaries after the mains (by 4 degrees).

 

[GoBigBlue1984]

Also wondering why the 106.5 exhaust roof from the factory with the relatively short stroke (for an echo). Do you thing the increased transfer area allows for better filling and allows for more swept volume in this beast?

A good amount of transfer area at the wall. That’s for sure. What caught my attention is the transfer tunnel volume. Very tight in there. Some casting obstructions to direct charge as well (inside the tunnel).

 

[Woodpecker]

Thanks for doing this Brett! Stoked to see what you come up with...

 

[drf256]

Thanks Al, we’ve been well. Covid has been more prevalent around here as of late. Though nothing like you guys have experienced up there, I’d say.

Volume is up here, but the illness seems milder. The problem has been that as total cases have increased the total severe cases have as well. Seems to be less of a percentage of really sick ones, but the total number is high. I got my second vaccine shot this past Monday and can’t wait for some immunity to kick in. I get exposed every single day and never caught it.

 

[Motorka]

Liked Mitch youtube port yob . Hope to see his work on 357/359.

 

[GoBigBlue1984]

Volume is up here, but the illness seems milder. The problem has been that as total cases have increased the total severe cases have as well. Seems to be less of a percentage of really sick ones, but the total number is high. I got my second vaccine shot this past Monday and can’t wait for some immunity to kick in. I get exposed every single day and never caught it.

My sister in law is an RN at our local Baptist East Hospital. Not a big town where the hospital is (30k). She said today that they’ve been seeing cardiac episodes in patients 20-30 years of age. That’s terrifying.

 

[GoBigBlue1984]

Thanks for doing this Brett! Stoked to see what you come up with...

Thank you sir. Just getting back into it tonight.

 

[GoBigBlue1984]

Here you can see the transfers after I roughed them in....with the transfer cover installed. You can see how this would cause some disruption.




Transfers roughed in

 

[GoBigBlue1984]

Staggered the transfers for the time being. 5 and 3 degrees respectively from the primaries on down. Wanna see something first.

Different saw and cylinder design, but I had an Ace Morgan finger ported 288 cylinder that ran really good. I actually stole the port timing from that saw and I build all of my 288’s with those numbers for the most part.

His fingers opened up 4-5 degrees after his mains. I thought I’d outsmart him and open my fingers up a few degrees before the mains. Hell, I tried opening them up simultaneously but never could replicate the power that cylinder had.

The only thing I could come up with is that opening the finger ports first, slows velocity in the mains. I have no idea how to quantify that.....but take that for what it’s worth.

so I’m gonna start with staggered transfers in this saw. David Young actually recommended that I do this (when I first mentioned tearing this saw down). That David young is one sharp cookie. I’ve come to highly respect his opinion.

 

[huskihl]

I’ve got a couple of these Echos coming. Curious to see how yours reacts to what you’ve done

 

[GoBigBlue1984]

Liked Mitch youtube port yob . Hope to see his work on 357/359.

I did too, I’ve enjoyed his vids for sometime.

 

[jacob j.]

Different saw and cylinder design, but I had an Ace Morgan finger ported 288 cylinder that ran really good.

Ace was an unreal engine builder and tuner. His nephew told me that Ace could tell you how fast a saw was going to be just by holding the cylinder in
his hand and eyeballing the ports. He built a kartsaw for my uncle in the early 70's and my uncle said that was only chainsaw that ever scared him, even
after many years cutting timber full time.

He didn't just work on chainsaws either, he built many good running bike engines and tuned some VW motors for the dune buggies here.

 

[GoBigBlue1984]

Ace was an unreal engine builder and tuner. His nephew told me that Ace could tell you how fast a saw was going to be just by holding the cylinder in
his hand and eyeballing the ports. He built a kartsaw for my uncle in the early 70's and my uncle said that was only chainsaw that ever scared him, even
after many years cutting timber full time.

He didn't just work on chainsaws either, he built many good running bike engines and tuned some VW motors for the dune buggies here.

To be able to sit and have a beer or two with Ace Morgan.....

 

[GoBigBlue1984]

A piston with a taller crown would be great on this saw. I feel it needs more compression. Not terrible, as it is. Probably 165-170....ish. That’s at .019/.020 squish with .030 from the band.

Got it back together and fixing to make some cuts and get some video. I will add that Throttle response improved a fair amount.

 

[Redfin]

Did I miss where you are at in durations Brett?

 

[jacob j.]

To be able to sit and have a beer or two with Ace Morgan.....

That would be a great thing. Last time I saw Ace was in 2004 and he'd come up with a good recipe for the 385 for fallers (I don't think the 390 had come out yet).

Last time I saw his nephew was on a fire 2007. I don't think his nephew is cutting anymore. In fact, I think pretty much the entire family is out of the woods now.

In regard to your build, I think it should be pretty easy to come up with a taller 51mm piston. What's the wrist pin on that one - 12mm?

 

[Nutball]

Shindaiwa 757 was 51mm http://acresinternet.com/cscc.nsf/e...59992a4acf7c73d488256e7300535348?OpenDocument

 

[qurotro]

Shindaiwa 757 was 51mm http://acresinternet.com/cscc.nsf/e...59992a4acf7c73d488256e7300535348?OpenDocument

So Japanese..

 

[drf256]

A piston with a taller crown would be great on this saw. I feel it needs more compression. Not terrible, as it is. Probably 165-170....ish. That’s at .019/.020 squish with .030 from the band.

Got it back together and fixing to make some cuts and get some video. I will add that Throttle response improved a fair amount.

Could weld a popup, adds weight though.

 

[Nutball]

So Japanese..

Yeah, so go with Japanese parts.