High altitude cutting

[Woodsman_26]

I threw the ms661 on the list for a heavy duty contender for my sawmilling I plan on doing. Not sure how much I'm going to do yet though.

 

[bwalker]

I'm unsure about the electronics but the power to weight in the newer saws is so much better and I don't see alot of used saws to pick from in my area. I am also itching for a new saw since I have never had one. So I figured I would choose one of the newer saws once I figure out which is better suited for myself and the cutting I do.

If you want a 500I you should get one. Relatively speaking saws are a cheap hobby.

 

[Ted Jenkins]

Keep in mind that even if the Mtronic or autotune perfectly tunes the saw, you'll never get sea level power out of them. Subtract as much as 20% loss per 5000ft.

Here is what I do for high altitude. I clean up the ports with out changing them too much. I them sand blast the ports to regain an abrasive texture. file the cylinder about 20 thousands. When the cylinder is close to touching the top of the piston I stop. I take my dremal tool and reshape the head so as to fit the piston tight with less than 20 thousandth. I open up the muffler a bit and Finally advance the timing 5 to 7 degrees. When this is done I can almost not realize I am at 10,000 feet. I would guess maybe a 5% reduction in power. When you are done the saw is for high altitude only but runs very sweet. Thanks

 

[Woodsman_26]

If you want a 500I you should get one. Relatively speaking saws are a cheap hobby.

I can tell you I'm definitely leaning that way especially with the max bar size.

 

[Woodsman_26]

Here is what I do for high altitude. I clean up the ports with out changing them too much. I them sand blast the ports to regain an abrasive texture. file the cylinder about 20 thousands. When the cylinder is close to touching the top of the piston I stop. I take my dremal tool and reshape the head so as to fit the piston tight with less than 20 thousandth. I open up the muffler a bit and Finally advance the timing 5 to 7 degrees. When this is done I can almost not realize I am at 10,000 feet. I would guess maybe a 5% reduction in power. When you are done the saw is for high altitude only but runs very sweet. Thanks

Thanks for sharing. That's great info.

 

[8150 Steve]

462's and 500i's are working well up in Crested Butte. 8500-11k.

Did your 500i run well out of the gate? Mine doesn't want to start at 10k

 

[8150 Steve]

Here is what I do for high altitude. I clean up the ports with out changing them too much. I them sand blast the ports to regain an abrasive texture. file the cylinder about 20 thousands. When the cylinder is close to touching the top of the piston I stop. I take my dremal tool and reshape the head so as to fit the piston tight with less than 20 thousandth. I open up the muffler a bit and Finally advance the timing 5 to 7 degrees. When this is done I can almost not realize I am at 10,000 feet. I would guess maybe a 5% reduction in power. When you are done the saw is for high altitude only but runs very sweet. Thanks

Are you in Leadville? Any interest in doing some work on a couple saws to set them up for 10k?

 

[Officerdangle]

Watching this thread since my Echo CS-800p ,24" bar is not impressive at 9600'
Keeping an eye on Husky 70cc saws.

 

[Ketchup]

Did your 500i run well out of the gate? Mine doesn't want to start at 10k

Did you calibrate the saw for your elevation? That may help.

 

[HansFranz]

Since air is only about 70% as dense at 10k feet as at sea level, does that mean you lose 30% of your power at 10k feet elevation?

 

[OM617YOTA]

Since air is only about 70% as dense at 10k feet as at sea level, does that mean you lose 30% of your power at 10k feet elevation?

3% power loss per 1k feet altitude gained. So yes, exactly that.

Modern vehicles, which are able to tune their fuel and ignition maps on the go, are less effected, but still effected. Chainsaws, big time.

 

[Ted Jenkins]

Are you in Leadville? Any interest in doing some work on a couple saws to set them up for 10k?

I live mostly in Southern California. The San Bernardino Mountains. As far as saw modifications are concerned this is not rocket science stuff. At 10,000 feet air is thinner so compensate. Air and fuel burn slower so advance the timing. The ports need as much air flowing through them as possible so enlarge them to the point where as all the casting flaws have been removed then some how make the ports not real smooth so as to not stop the air flowing through them. A typical gasket delete will go a long ways to increase the combustion. A good savvy saw guru can do this. Thanks

 

[8150 Steve]

Did you calibrate the saw for your elevation? That may help.

Yes. Runs great, just takes forever to get it started.