NE 346XP - Affects of Cat Muffler & Muffler Mod - Porting & Popup To Come

[Trigger Man]

i just got mine and didnt get a chance to see it go but i can tell its very snappy

Did'nt you just post in your other thread that you tryed it out on some small stuff?

 

[lone wolf]

Did'nt you just post in your other thread that you tryed it out on some small stuff?

yes but like couple seconds it was a small piece on the ground not even a log i cant wait to cut somthing

 

[BigUglySquirrel]

Now I'm not trying to hijack Brads thread, but since he's off getting carpal tunnel from his die grinders and dremels, maybe I can regail you all with a little story.

I was on a LARGE removal the first time I got to meet Brad and his arsenal of high RPM toys. I have to say, I was skeptical but excited to see what a tricked saw could do. Now it has to be said, Brad is one of those guys that you just like right off the bat. He's polite, well spoken and genuinely well.... a nice guy. The real fun starts when you turn the conversation to saws. His eyes light up and he starts talking faster and faster...like he's afraid he'll run out of time before he'll run out of things he'd love to tell you. In short, the dude KNOWS his stuff and he'd passionate about it. The real kicker is he LOVES to share what he's learned and his theories. So, enough about Brad.

His cache was QUITE impressive. Off-hand I recall a 346xp, 440 with a 460 topend, a super clean 084, and a tricked 660. There was also a Johnsered I believe? Little help there Brad..

At any rate, my mouth was watering and it wasn't long before I got to see what a real saw was all about. I got to see them all run, and I got to run a few myself (thank you Brad... I think! LOL! You created a fiend...) but BY FAR, for me the most impressive was the unassuming, somewhat diminutive looking 346xp.

We recently got a stock 346xp and it's a good saw for what it is. It's handy in the tree and it's "alright" on the ground as long as the chain is in shape. So I was shocked when it was his first call for a large old-growth oak.

From the moment he fired it up, I was entranced. The sound of this thing!! Oh my GOD! What really killed me was how EFFORTLESSLY this thing handled the load! I watched him bury the bar all day and the thing was just relentless! Here I was, cutting with a 24" bar on a stock, well-cared-for 372xp and he's running through the cut faster than I am....with a saw that is FAR more manueverable and WAY lighter! Which left me thinking, "Now what is wrong with this picture?! I bet his lower back isn't even getting tight yet....well that little saw isn't much bigger than a popcorn fart! Why am I still hauling this big heavy mother mother around? Well I guess I'd use our 346, too....if it would cut like THAT! I might need to get me one of those..."

Yes, the rest of his saws were impressive and I found myself shaking my head in disbelief several times, but I made up my mind that day. I will own one of Brads Snelling's pop-top, ported 346xp timber piranhas before I clock out....for now I've got a few 200T's that are going to need a little massage....and a 365 Special, and a 395xp, and a 361.....


Hope I didn't ramble too much for you guys... just wanted to share my experience with everyone

 

[Trigger Man]

Now I'm not trying to hijack Brads thread, but since he's off getting carpal tunnel from his die grinders and dremels, maybe I can regail you all with a little story.

I was on a LARGE removal the first time I got to meet Brad and his arsenal of high RPM toys. I have to say, I was skeptical but excited to see what a tricked saw could do. Now it has to be said, Brad is one of those guys that you just like right off the bat. He's polite, well spoken and genuinely well.... a nice guy. The real fun starts when you turn the conversation to saws. His eyes light up and he starts talking faster and faster...like he's afraid he'll run out of time before he'll run out of things he'd love to tell you. In short, the dude KNOWS his stuff and he'd passionate about it. The real kicker is he LOVES to share what he's learned and his theories. So, enough about Brad.

His cache was QUITE impressive. Off-hand I recall a 346xp, 440 with a 460 topend, a super clean 084, and a tricked 660. There was also a Johnsered I believe? Little help there Brad..

At any rate, my mouth was watering and it wasn't long before I got to see what a real saw was all about. I got to see them all run, and I got to run a few myself (thank you Brad... I think! LOL! You created a fiend...) but BY FAR, for me the most impressive was the unassuming, somewhat diminutive looking 346xp.

We recently got a stock 346xp and it's a good saw for what it is. It's handy in the tree and it's "alright" on the ground as long as the chain is in shape. So I was shocked when it was his first call for a large old-growth oak.

From the moment he fired it up, I was entranced. The sound of this thing!! Oh my GOD! What really killed me was how EFFORTLESSLY this thing handled the load! I watched him bury the bar all day and the thing was just relentless! Here I was, cutting with a 24" bar on a stock, well-cared-for 372xp and he's running through the cut faster than I am....with a saw that is FAR more manueverable and WAY lighter! Which left me thinking, "Now what is wrong with this picture?! I bet his lower back isn't even getting tight yet....well that little saw isn't much bigger than a popcorn fart! Why am I still hauling this big heavy mother mother around? Well I guess I'd use our 346, too....if it would cut like THAT! I might need to get me one of those..."

Yes, the rest of his saws were impressive and I found myself shaking my head in disbelief several times, but I made up my mind that day. I will own one of Brads Snelling's pop-top, ported 346xp timber piranhas before I clock out....for now I've got a few 200T's that are going to need a little massage....and a 365 Special, and a 395xp, and a 361.....


Hope I didn't ramble too much for you guys... just wanted to share my experience with everyone

Ramble away, Not to many care about saws the way brad seems to, he's very valuable to the site. Also not everyone is capable and/or willing to explain everything in detail like brad is willing to do. He's one of a kind in this world for sure.

 

[blsnelling]

Now I'm not trying to hijack Brads thread, but since he's off getting carpal tunnel from his die grinders and dremels, maybe I can regail you all with a little story................

Hey Chris! Good to see you around. It took me a second to figure out who it was that knew me so well, lol. I didn't know your AS username.

This little bugger is liable to out perform my 346. I've actually never even had a degree wheel on mine. The exhaust was really low on this one. Perhaps mine is as well. I'll certainly want to compare them before I send this one off.

Anyway, the porting is nearly done. I'm finishing up the transfers, and then have to put the final finish on the exhaust. I may have this thing back together yet tonight.

 

[blsnelling]

What Chris didn't tell you is that he's one of those crazy, fearless, adrenaline junkies that swings from trees 100' in the air! Yeah, one of those guys. He's one of the guys you saw in the video I made of dropping that nearly 60" DBH Oak tree a few weeks ago. Chris is quite the nice guy himself. Matter of fact, he loaned me his 200T to run against mine today. Thanks Chris!

The porting is done. I'm off to the garage to clean things up, make a thin gasket, and bolt it back together. I'm anxious to see what compression is after raising the exhaust about 7°. What ever I lost, I should more than make up with the popup.

 

[blsnelling]

The saw's back together and running like a top. Obviously, it's too late to put it in wood though. It's turning about 16K. The exhaust came out exactly where I wanted it, at 100°. I raised it 7° which is about .070"! Now here's what's wild. I've got more compression than I started with. Lowering the squish down to about .016" from .027" more than made up for the exhaust port raising. Compression is now 150 PSI. A .035" popup will have that up nicely. I'm shooting for a final squish of .018 after the machine work. When it comes back apart, I may raise the transfers a little more. They're still at 123°. I was shooting for 120°. I'll just have to wait and see how it runs. If I wasn't doing the popup, this saw would be done and going out tomorrow.

 

[parrisw]

Here are the measurements with the gasket out.
-Squish .013"
- Exhaust 108°
- Transfers 123°
- Intake 76°

Here's the plan.

- Turn a .035" popup on the piston crown, leaving .100" crown thickness.
- Mill cylinder base .030", for a final squish of .018".
- 100° Exhaust
- 120° Transfers
- 80° Intake
- Widen intake & exhaust ports to 70% of bore, as measered on the curve of the cylinder wall. Some go across the chord, which makes it a little wider yet.
- Widen and angle rear transfers towards the intake port.

What's the reason for the difference in timing? How come your going with less timing after porting?

 

[Terry Syd]

Timing/duration

Those aren't duration numbers, they are degrees from TDC.

It confuses me too as I think in duration terms. I have to convert them to understand them.

If the exhaust opens at 100 degrees after top dead center, then there is 80 degrees left before bottom dead center. Multiply that by 2 and get 160 degrees of duration.

 

[parrisw]

Those aren't duration numbers, they are degrees from TDC.

I confuses me too as I think in duration terms. I have to convert them to understand them.

If the exhaust opens at 100 degrees after top dead center, then there is 80 degrees left before bottom dead center. Multiply that by 2 and get 160 degrees of duration.

Ahhh ok. Makes sense now.

 

[dingeryote]

opcorn:

Seriously.

Good stuff Brad!

The MM, details and comments on the porting were music to the ears and eyes.
It IS appreciated.

Thanks!
Dingeryote

 

[Guarddog1]

The saw's back together and running like a top. Obviously, it's too late to put it in wood though. It's turning about 16K. The exhaust came out exactly where I wanted it, at 100°. I raised it 7° which is about .070"! Now here's what's wild. I've got more compression than I started with. Lowering the squish down to about .016" from .027" more than made up for the exhaust port raising. Compression is now 150 PSI. A .035" popup will have that up nicely. I'm shooting for a final squish of .018 after the machine work. When it comes back apart, I may raise the transfers a little more. They're still at 123°. I was shooting for 120°. I'll just have to wait and see how it runs. If I wasn't doing the popup, this saw would be done and going out tomorrow.

What piston are you going to use for the pop up part # please and were the heck are the pics? Can you post one of the machine work to the piston will you have the step tapered to the center of the piston or just leave a .035 step with a sharp edge?

 

[blsnelling]

I'll be using the original piston. The crown is .135" thick above the ring groove. .100" is considered the minimum safe thickness. So I will be going with a .035" tall popup. Squish without a gasket is currently .013". So I will take .030" off the cylinder base to give a final squish of .018".

I'll let FATGUY fill you in on the machining details. Hey Nik!!!!!!!!!!!

 

[FATGUY]

Hey Brad!!

 

[Guarddog1]

I'll be using the original piston. The crown is .135" thick above the ring groove. .100" is considered the minimum safe thickness. So I will be going with a .035" tall popup. Squish without a gasket is currently .013". So I will take .030" off the cylinder base to give a final squish of .018".

I'll let FATGUY fill you in on the machining details. Hey Nik!!!!!!!!!!!

So that is why you raised the exhuast that amout correct? To make up for the machining of the base.

 

[blsnelling]

So that is why you raised the exhuast that amout correct? To make up for the machining of the base.

Not at all. Putting a popup on the piston does not affect exhaust or transfer port timing at all. The cylinder is machined to come down with the piston crown. I raised the exhaust because it was much lower than what I wanted. I wanted more exhaust duration. That will also have the affect of giving me more blowdown time, which was very short before. Blowdown is calculated from when the exhaust starts opening until the transfers start opening. In the case of this saw, it starts at 100° and ends at 123°, for a blowdown of 23°.

 

[Guarddog1]

Not at all. Putting a popup on the piston does not affect exhaust or transfer port timing at all. The cylinder is machined to come down with the piston crown. I raised the exhaust because it was much lower than what I wanted. I wanted more exhaust duration. That will also have the affect of giving me more blowdown time, which was very short before. Blowdown is calculated from when the exhaust starts opening until the transfers start opening. In the case of this saw, it starts at 100° and ends at 123°, for a blowdown of 23°.

But lowering the entire jug by means of removing the gasket and macinig the base woould effect port timing that is what I was refering to not the blowdown that would remain constant unless manual grinding of one or the other took place correct. And just another question if you lower the squish band .030 the edge of the piston would then clear the port at .030faster is that taken into consideration in port timing. Thanks for taking the time to answer my questions I am not giving you hard time just trying to learn.

Thanks Bill

 

[blsnelling]

If the top of the piston and the cylinder come down together, there is no change in port timing.

 

[Guarddog1]

If the top of the piston and the cylinder come down together, there is no change in port timing.

Roger that understood huh missed that as simple as it is.

 

[blsnelling]

Roger that understood huh missed that as simple as it is.

It just takes some time and thinking to get your head around some of this stuff. Now I'll try and confuse you While exhaust and transfer port timing doesn't change, intake timing does. Because the bottom of the piston skirt isn't changing, and the intake port is coming down, intake duration is increased. It's kind of like automatic porting, lol. I kept this in mind when I ported it. I left it about 4° higher than what I want the final number.