359 port timing numbers

[huskihl]

The higher the exhaust port, the more rpms (but narrower power band..ie "peaky")

I like it and am wondering what it changes like speed torque etc. what effect or how what changing it does.

 

[jonsered 535]

The higher the exhaust port, the more rpms (but narrower power band..ie "peaky")

So I will gain more rpm in the cut and a little more speed in junking time by putting it at 101 ???

 

[sunfish]

How much did you widen them a 1/16 or so on each side??

I usually widen around 1/8" off each side. I've done 3-4 saws this way without a degree wheel and got real good gains. I'm cutting bases on a lathe now, but not the squish band.

 

[jonsered 535]

I would leave the intake at 78. It will give the saw a little more torque. You can also make the floor of the intake flat and square off the corners.

Should I do the same with ex make it a little flatter or keep the same shape as it is now

 

[sunfish]

Should I do the same with ex make it a little flatter or keep the same shape as it is now

Top of the ex port needs to stay domed, or rounded, not flat.

 

[ELECT6845]

Should I do the same with ex make it a little flatter or keep the same shape as it is now

Keep the shape the same. The rings have to pass over the port and if you square it to much it will reduce the life of the ring.

 

[jonsered 535]

What exactly will bringing my exhaust up to 101 from the 105 I have now do to the saw and how will it perform cookie cutting in the wood???? Compared to now

 

[jonsered 535]

I usually widen around 1/8" off each side. I've done 3-4 saws this way without a degree wheel and got real good gains. I'm cutting bases on a lathe now, but not the squish band.

Do I take the 1/8 off the intake sides as well on the width

 

[jonsered 535]

I marked the piston with a pencil along the stroke of the piston in the port and no trouble taking the 1/8 off probably 5/16 there on the exhaust side before the skirt is open

 

[sunfish]

Do I take the 1/8 off the intake sides as well on the width

Yes, I widen both ports the same amount. A little over 1/8'' is fine as well.

 

[jonsered 535]

Thanks everyone I am ready to get started now, if anyone else has any input or can think of anything else that will help me please post.
One more thing I have 2 - 359's this one was working and the other one I got tired and bored with waiting on parts to rebuild it, so here i am now with this one pulled apart but I have a meteor piston for the other one and have a Hultz one I got for6 bucks wondering if I should use the hultz on this or not will it be reliable, looking at it looks pretty good not sure if the metal is the same quality or not

 

[sunfish]

I would leave the exhaust hight alone & not hog out the lower transfers much. There is a little power in raising the upper transfer a bit, I'd go about .030-.040". Just don't over do it.

 

[jonsered 535]

Got my cylinder matched to my case where the gasket was didn't know how much to take to weaken it to much but lots there

 

[huskihl]

On the exhaust side, leave at least. 050" for the skirt to seal against the wall. On the intake, leave at least .050" for same reason but also stay away from your ring ends. Ring ends have to be supported by the wall

 

[jonsered 535]

I would leave the exhaust high alone & not hog out the lower transfers much. There is a little power in raising the upper transfer a bit, I'd go about .030-.040". Just don't over do it.

so I should leave my exhaust at 105 then.????
Right now my xfr are at 122.5* and you say I should raise them to 120????

 

[mdavlee]

102 and 120 would be fine.

 

[jonsered 535]

102 and 120 would be fine.

I know i'm full of questions but i'm a jack of all trades master of none lol so I have to ask another one lol
102* on the exhaust and 120 xfr right lol???? just don't want to shag this one up.

 

[mdavlee]

Yeah

 

[jonsered 535]

I have a buddy of mine that I cut firewood with, that also has a 359 and I want to show him I can do this and when done will out do his for power and speed lol. and I would like to put a smile on mine and his face after its all done. bragging rights lol.
I do have a 2003 arctic cat f7 that's been ported not by me but tuned and clutched by me that I have won 700 improved with the last 2 years in 660 ft snow drags.
now if I can get this 359 ported right I will be happy with all you guys help Thanks and keep the suggestions coming.

 

[jonsered 535]

Well everyone I need a moral booster this takes a while, I keep telling myself that there is good gains in this to keep going lol. That saw builders must have a lot of patience for this