I started porting on the exhaust side first. I didn't do any measuring other than getting my width no closer than 2mm of a skirt end or a ring end. So I ended up taking 1.3mm off each end. I haven't tried chamfering it let because my bits seem to short. But I was running out of time so I didn't try. I was more concerned about the width and shape for now. I felt kinda rushed from the time I grabbed the cylinder and made my measurements to this point was about 2 hours
Atempt to port this junk MS460 P&C first
- Thread starter davhul
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I started porting on the exhaust side first. I didn't do any measuring other than getting my width no closer than 2mm of a skirt end or a ring end. So I ended up taking 1.3mm off each end. I haven't tried chamfering it let because my bits seem to short. But I was running out of time so I didn't try. I was more concerned about the width and shape for now. I felt kinda rushed from the time I grabbed the cylinder and made my measurements to this point was about 2 hours
drf255
BAD CAD
The left side roof seems a bit too square for my liking. Did you raise or lower the roof/floor at all?
Overall looks pretty darn good I'd have to say.
The 044/6 run pretty darn well with a small squish cut, base cut to tighten squish, muff mod and timing advance. So well that I have begun to rethink my strategy on the model.
Here's an 044 with stock ports and .010 from the band. The saw 4 stroked to 16k. Here it is fat at 15k.
Overall looks pretty darn good I'd have to say.
The 044/6 run pretty darn well with a small squish cut, base cut to tighten squish, muff mod and timing advance. So well that I have begun to rethink my strategy on the model.
Here's an 044 with stock ports and .010 from the band. The saw 4 stroked to 16k. Here it is fat at 15k.
The left side was the side I started on first. I can just radius the corner down and it should be good then right. No I didn't raise or lower just cleaned the carbon off the edge with a sanding roll. Right now on my good cylinder my squish is at .025 with factory gasket. Should it be around .20 like the 660 that's what I've read up on most since I thought I would do it first.
On the intake side I can't take any off the right side as it already close to the skirt. And just a little off the left. So I'll just do more smoothing more than anything. On the bottom of the transfers should I tapper them to? How much timing does it like?
On the intake side I can't take any off the right side as it already close to the skirt. And just a little off the left. So I'll just do more smoothing more than anything. On the bottom of the transfers should I tapper them to? How much timing does it like?
IMHO, squarish corners are good, as long as the roof is properly curve all the way to the corner. Personally, I would want the right side to look like the left side.
That's kinda what I was thinking from the reading I've done. I hate to say I only used a dremel with different bits. I probably need to slow down and use some files next time.
This is how my other jug marked out. The port is offset some. This is the intake side
I made my marks on a heavy piece of plastic that's straight on all edges. It made it easy as I could see through it and line up on the port edge and I had flush against the squish so it's straight. Not sure if there's a better way but that's what I came up with.
You can make the intake really square since rings don't travel over it.
when you do this, what is the best tool/tools to use? to make the left more like the right it looks like you would actually remove a lot of material or maybe its the angle of the camera and my inexperience.
drf255
BAD CAD
You can smooth, but don't remove the hump on the intake side on the transfer tunnel. It's almost counterintuitive when you stare down the tunnel, but it's there to force charge towards the intake wall. Looks like you've ground it out some.
A lot of guys make great power with stock uppers and stock tunnels.
A lot of guys make great power with stock uppers and stock tunnels.
I did round it some but it does look like I took a lot off in that that pic. So I went and looked at the cyl again. It's not a as dramatic as the pic so I'll stay away from anymore of that. Thanks for the tip
I did the exhaust on the one I'm using. It must be the way I'm holding the bit because Its hard to duplicate the same on the other side. I seem to square it on the left and more round on the right. but I don't think it's to bad I stopped before I went to far.I cleaned up and tapered the piston widows, got the squish at .019 I had to take .005 off the base with sandpaper and a peace of glass rotating every 10 strokes. I fired it up and it sounds good with fast crisp throttle response. I'm thinking about trying the timing at
7 degrees does that sound good?Question: About how much four stroking is a safe tune for a ported saw? right now I have it at 14,000 and its stroking pretty good. It starts to smooth out a lot at about
15,000 -15,200 so I know that's on the top side. Thanks for everyone's input so far.
7 degrees does that sound good?Question: About how much four stroking is a safe tune for a ported saw? right now I have it at 14,000 and its stroking pretty good. It starts to smooth out a lot at about
15,000 -15,200 so I know that's on the top side. Thanks for everyone's input so far.
For a safe tune, you want to make sure it is 4 stroking out of the cut, and not when it is cutting - small wood being the exception, as it won't put enough load on the saw. You want to to return to 4 stroking almost immediately when you lift in the cut.
I like to tune in the wood as different saws can sound and react differently. I tune as above, but also test how hard it is to bog the saw when cutting. Sometimes a 1/8th turn or less leaner can give the saw quite a bit more power, but it still returns to 4 stroking almost instantly when lifted in the cut. Play around with different settings and you will quickly get a feel for how the saw reacts. I normally end up about 1/8th of a turn richer than where I think it had the most power.
I like to tune in the wood as different saws can sound and react differently. I tune as above, but also test how hard it is to bog the saw when cutting. Sometimes a 1/8th turn or less leaner can give the saw quite a bit more power, but it still returns to 4 stroking almost instantly when lifted in the cut. Play around with different settings and you will quickly get a feel for how the saw reacts. I normally end up about 1/8th of a turn richer than where I think it had the most power.
drf255
BAD CAD
I'll add to use RPM as a reference point only in any modified saw. Has to be tuned in the cut as stated above.
The OEM rpm recommendations come from extensive testing to find the right tune with all the exact same parts. Once you change anything, that goes out the window.
The OEM rpm recommendations come from extensive testing to find the right tune with all the exact same parts. Once you change anything, that goes out the window.
That's purdy!
