Randydb
ArboristSite Lurker
So? I see a lot of post mentioning that a saw has been ported. Obviously an upgrade that improves performance, but what is done when you port a saw?
Randy
Randy
Newbie Question...What does it mean when it is "ported?"
- Thread starter Randydb
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CapitaineHaddoc
European Westcoaster
At first, a ported saw could be a race ported saw or a woods ported saw. Most of saws on AS are woods ported, this means they are built to be used everyday as work saws.
The porting job may vary depending the saw. On most saws, builders have to use a lathe on the cylinder to cut the base of the cylinder to increase compression. This will also advance the cylinder ports timings. Then, they cur a crown around the piston or they cut the squish band (around the combustion chamber).
Then, they have to change the ports dimensions (not necessary on all saws). Tipycally, ports are slightly enlarged, or raised to change the timings and durations. And sometimes, to advance the timings a little more, they have to grind the flywheel key to change the flywheel position.
The mufflers are also modded. Enlarging the exhaust outlet or add another one. CAT mufflers need more work, internal baffles have to be removed most of time.
Lot of pictures and explanations here:
http://www.wickedworksaw.com/woodsporting.htm
The porting job may vary depending the saw. On most saws, builders have to use a lathe on the cylinder to cut the base of the cylinder to increase compression. This will also advance the cylinder ports timings. Then, they cur a crown around the piston or they cut the squish band (around the combustion chamber).
Then, they have to change the ports dimensions (not necessary on all saws). Tipycally, ports are slightly enlarged, or raised to change the timings and durations. And sometimes, to advance the timings a little more, they have to grind the flywheel key to change the flywheel position.
The mufflers are also modded. Enlarging the exhaust outlet or add another one. CAT mufflers need more work, internal baffles have to be removed most of time.
Lot of pictures and explanations here:
http://www.wickedworksaw.com/woodsporting.htm
Randydb
ArboristSite Lurker
Okay...that site you referenced makes it pretty clear. Interesting. Funny what a different configuration can make for performance.
CapitaineHaddoc
European Westcoaster
Yep, a good porting job can really wake up a saw. There are really good builders on AS, they often gain around 40% gain over a stock saw.
Randydb
ArboristSite Lurker
I bought a ported 266 xp with duel exhaust today. The guy I got it from was a chainsaw mechanic for years before going to work for the government in the forest fire suppression unit repairing pumps for them. I spent 2 hours with him. He talked my ear off and really knew his stuff. Was explaining what made a good porting job and showing me another saw he was in the middle of porting. It was interesting but some of it was beyond me. But when I was done talking with him and taking the saw apart I was convinced I had a pretty good saw. Thanks for the info on porting. It got me reading and helped me recognize what I was looking at when he pointed out the 266 and said it was ported.
TimberWolf530
ArboristSite Guru
Just a ballpark figure, what does it cost to do a port job?
Most builders charge around $300.
Randydb
ArboristSite Lurker
So, with high performance cars, they tend to be more finicky and need to be adjusted and tuned up more often. Is this true of ported chainsaws? Just asking seeing as I own one now.
Deets066
Firewood hack
Not finicky, just need to be tuned correctly and adjusted sometimes with different fuel/ oil mix or temperature change
Nizina
ArboristSite Lurker
Wouldn't porting screw up the mirochip program in a M-tronic type chainsaw? In other words, can an M-tronic type chainsaw be ported and still have it work properly?
Rev
They Is No Tomorrow!!!
They have a range from the base calibration which so far allows for some expansion in time/area within the ports. I didn't see it mentioned yet, some models ping off the rev limiter embedded in the coil design made to prevent over rev-ing. We are looking for some mild over-rev to enhance the saw's capability in most cases, especially to wind up quick for limbing. Sometimes it requires a coil 'upgrade'=$$.
Nizina
ArboristSite Lurker
I'm not going to pretend to know much about how's they work but it's been proven that those systems can compensate for changes to the combustion chamber and port timing. However there is a limit and certainty no definitive rules that explain the limits. That's all skill of the craft/builder and usually determined through trial and error/personal experience.
Mastermind
Work Saw Specialist
Porting chainsaws is a silly fad. I'd say it's something that will never really catch on.
Nizina
ArboristSite Lurker
I guess I could understand porting a chainsaw that you had for several years and wanted more power but didn't want to buy a new saw. But I don't know why you would want to port a new chainsaw rather than just buying a larger saw in the first place -- but maybe to take advantage of a lighter new saw and needing more power. I'm considering a new saw in the 90 cc range for milling. Maybe a lighter ported saw than the 2188/ms661/395xp category would make sense if I wanted to do forestry work with it as well.
Mastermind
Work Saw Specialist
Dangerous and irresponsible too. What about the shrapnel from when it flies apart?
Deets066
Firewood hack
Porting saws is just plain stupid, especially new ones
Rev
They Is No Tomorrow!!!
Probably better just to switch carburetor.
It's one of those things that you just have to experience before you will truly understand... for me it's just a whole lot more fun to run a ported saw.
REPORTED!!!
I find that language offensive!
