Husky 455 to 460 upgrade and porting

[mettee]

View attachment 647073
Just a little of what I did....
In the stratosphere port you can see the onerlap of the piston....I market that and removed that from the piston and just did clean up to the port itself,
The intake port I brought the top corners up to add volume of intake. I didn’t go drastic as I believe the ring end gap is in the center of the port. It was very noticeable what was done when finished. Make sure to really bevel and smooth the edges of the port.
I also took 20 thousands off the bottom of the piston where it opens on the intake.

So my question...even though the intake boot from the carb is that shape it's still beneficial to open it like that behind the boot?

 

[usmcbuckwild]

So my question...even though the intake boot from the carb is that shape it's still beneficial to open it like that behind the boot?

Its got the plastic intake manifold, right? Flow match the intake to the port.

 

[Poleman]

On your lower transfers I cleaned them up and raised/lowered the cylinder wall to allow more mix to be pushed into them from the crank.
The boot shape doesn’t matter as long as it’s a good fit. The mix coming in will disperse to the shape and fill....this allows more mix to pass into the system as it opens up. That’s my theory on it. The saw was a torque monster.....I wish I would tried an unlimited coil on it now.....sold it first time out to a guy watching me/it cut. I let him try it and he liked it and wanted it....so I sold it. Have talked to him since and he loves it!!!

 

[mettee]

So I guess that confirms these saws have a limited coil. Is it possible that certain serial number saws might not be limited?

I have a black coil. Heck I'll change that sucker right out if it is.

 

[Poleman]

I was just going by what was already said about these saw. I never confirmed the color of the coil to be able to judge but an unlimited coil could help this saw after modding. It doesn’t need much but it would really top it off by raising the upper limit.
In comparison it would be like a ported 262 with a ton more bottom end. I like a torque saw over speed to be able to pull and restart in a kerf and power to start cutting. ( To many years cutting around power lines where you need a saw that starts in a cut and able to cut when needed because of what your doing and needing it to go in a specific space being released at a particular time.)

 

[usmcbuckwild]

From what I have seen with Husqy coils is Blue is limited and black is unlimited. No guarantee on that, but for the 3 series saws it holds true.

 

[Poleman]

Yes, that’s what I’ve always went by also. Has always held true from my experience.

 

[mettee]

The coil on this saw is black.

 

[mettee]

I ported out the plastic runner, it had some serious flow issues.

 

[mettee]

Okay so I'm really trying to figure out the upper transfer area.

I see some that make the ports "finger" forward more into the combustion area.

Right now

Flow is from bottom left upward to the right. That upper most right edge is where i see people remove material. I'm just unsure if it's worth the trouble here because it seems to have pretty nice flow.

 

[mettee]

This is masterminds port work, but ignore his upward finger that he adds to that transfer....the area I am curious about is the angle at which the upper transfers is at and if it should be ported more.

 

[usmcbuckwild]

This is masterminds port work, but ignore his upward finger that he adds to that transfer....the area I am curious about is the angle at which the upper transfers is at and if it should be ported more.

Different type of cylinder and piston combo. Progressive port on a non-strato port saw. Don’t forget that only about 50% of the air fuel mixture is coming through the transfers, the other 50% of straight air is coming through the strato ports.

 

[mettee]

I decided that I'm going to take a mold of the entire strato port transfer. Then we can look at what's what.

 

[usmcbuckwild]

I decided that I'm going to take a mold of the entire strato port transfer. Then we can look at what's what.

Well......... We’re waiting!

 

[mettee]

Finished my degree wheel. If anyone can chime in on getting the events mapped out that would be great!

I got this so far

Exhaust cracks at 104
Side piston cut outside crack at 53
Piston top cracks at the transfer at 118
Intake 268?

 

[mettee]

No more waiting

 

[mettee]

So what did I learn.

Well the exit into the upper cylinder looks to be an area for improvement.

The area in the runner "could" be made slightly bigger but...needs to maintain its shape change ratio to keep the speed up in the directional changes.

I really want to lay that upper opening out a little bit. It's close to the strato intake(intake side).

 

[usmcbuckwild]

You have to remember that the transfers start large “diameter” and are smaller in the cyl area to increase velocity. If the trasnfer output is too large you lose velocity which in turn means less high speed flow into the cylinder. This is an area where volume of a/f mix doesn’t trump velocity. With the velocity you “mixing” the a/f mix with the air coming in the strato ports and are also assisting in forcing the exhaust out (i know strato ports saws use the strato ports as main source to force out exhaust). Can’t get too crazy in increasing flow at the top of the transfers. Smoothing them and removing some casting flash isn’t going to hurt them, but increasing them may harm performance.

 

[mettee]

There is one sharp turn in the strato, it's where it dumps into the top of the cylinder, its 40 to 45 degrees or less.

My thought is to simply increase that to a 60 degree angle so the a/f flow easier. Hard to describe, I'll try and get a picture later, but I feel like it's a small change.

This is the angle I'm talking about, the port widens here, and has a much larger are than the rest of the port.

 

[usmcbuckwild]

That port tunnel shouldn’t be a problem. The 90 degree turn isn’t hurting anything as it maintains size the whole way through. The turn should help with turbulence to enhance “atomization”.