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Chainsaw Porting Theory

idiotwithasaw

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Ok I'll time mine when I get my piston stop in. I have a degree wheel setup thanks to @GoBigBlue1984 and need to learn to use it. I wish I had a right angle so I can do transfers, but they are just so dang expensive. Only reason I was asking about widening is because I no nothing about porting a saw and am afraid to grind up or down. I figured wider couldn't really hurt but I thought I would ask.
 

smokey7

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My only little pieces of advise is eyeball the whole package. Look closely and mark lines in the jug referencing ring ends and look at Port edges. You never want to have a ring end in a port bad things happen. That may nor apply to a 346 but surely will on other motors. Check recheck cut a little recheck, oh and recheck again, as a first timer it's very satisfying to get a gain from a motor.
 

GoBigBlue1984

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Ok I'll time mine when I get my piston stop in. I have a degree wheel setup thanks to @GoBigBlue1984 and need to learn to use it. I wish I had a right angle so I can do transfers, but they are just so dang expensive. Only reason I was asking about widening is because I no nothing about porting a saw and am afraid to grind up or down. I figured wider couldn't really hurt but I thought I would ask.
If you can wait Ben I'll do it for ya and show you how I go about all this. Just got too many saws to finish right now. Again, as Jason said earlier widening of the intake isn't always necessary and sometimes yields very little to nothing except a fuel hog. My first few saws I widened intake to the max and thought it was necessary. I will say that if you're gonna use a bigger boot ala stihl 290/390 then by all means go for it. The last ones that I've done I haven't touched the intake.
As far as exhaust goes I agree that some saws (like the 395) are close to max width already. You can widen a little but not much. Others, like the 660, can be widened a fair amount. I use ID Spring calipers to measure width. Stop by sometime when I'm grinding on some jugs, lots of good stuff going on lately with saw stuff. You know how it is with me though, might not be till after dark before I get out to the shop.
The greatest joy other than building a saw for yourself and seeing the gains, is building a saw for someone else and the smile they get coming out of a cut when you know they're thinking, wow.....this is much stronger than what I had.
I tape off my cylinder walls around the port for area to be cut.......image.png
 
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GoBigBlue1984

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Don't be afraid to try things out Ben. Ask questions. Too many knowledgeable guys on here to not ask questions. Randy told me on one of my early builds to practice practice practice on the cheap AM jugs and go from there. It doesn't take long to start to get comfortable. Having David to ask advice from and bounce ideas off of was/still is crucial for me. It's a baptism of fire of sorts. The main thing is do you have the desire to dive into it? If the answer is yes...... You'll do fine. This forum in particular is set up for this very thing........it's all at your fingertips. More than one way to F@c! this goat. Tape up your walls for cheap insurance and let'r rip.
 

jmssaws

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I've been trying to read and learn, but there's only one real way to gain knowledge and that's to do it. If I fark up an oem jug oh well it's the tuition.
Don't worry about messing up a cylinder,it's really hard to do with a 1/8" burr. Cylinders are made from vagina, there tough and don't wear out.
 

GoBigBlue1984

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Don't think there hasn't been many a lonely night when my wife has a "headache" where a 395 jug looks pretty damn appealing perched up over on the bench.......ports wiiiide open.......mmmm. No wonder beveling is so important.
 
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