Degreeing my first saw. Numbers not making sense. Help?

[MemphisMechanic]

12mm Stihl 044
Hyway cylinder
Meteor piston
No base gasket (Squish @ .028”)

The masking tape is stuck at the exact point where each event is observed through the spark plug hole or exhaust port, just the way countless YouTube videos have shown.

All of my numbers are much larger than the numbers I’ve seen guys post. I’ve checked each them three times and confirmed that the wheel has not slipped.

By my math, I’m at:
Exaust 179
Intake 144
Transfers 126

Please inform me of whatever my bonehead mistake might be.

 

[deye223]

It's obvious your a quarter turn out .
Don't worry just taking the piss

 

[CausticUC]

What numbers are you worried about? Your open and close are 180 degrees, if they were not, I'd be worried.

 

[cuinrearview]

You're just reading it wrong. I see E104 T121 I72.

 

[MemphisMechanic]

You're just reading it wrong. I see E104 T121 I72.

Ahh. <cue lightbulb>

I was looking at durations, not at when the ports open/close in relation to TCD.

Thanks. I’m going to take .008” off the cylinder base on a mill, then come back to do the port work.

Once, of course, I figure out what a good safe “middle of the road” starting numbers would be for a first timer. I don’t need it to scream, just want to take my time and carefully build one that pulls.

 

[cuinrearview]

100/120/80 is good spot to start

 

[MemphisMechanic]

100/120/80 is good spot to start

For an 044 in specific, or in general on Stihl’s, or in general on ~70cc saws?

I’ve been reading every thread and watching every youtube I can find on this stuff but I still don’t honestly know what numbers to shoot for. So thanks for the ballpark!

Thoughts on taking .008” off the cylinder base to bring the squish down to .020” - given the fact that I have the capability to machine it, I figure I might as well. Waiting on a couple of parts anyway.

 

[cuinrearview]

Setting your squish would be fine. If you can machine the squish band too to go further and add compression it would help. Plus you could get your intake number easier. The numbers I gave are just kind of a general number for most saws above 70cc. Specific models like different numbers though and with an aftermarket cylinder you never know. Maybe @huskihl will swing by and correct me.

 

[huskihl]

Setting your squish would be fine. If you can machine the squish band too to go further and add compression it would help. Plus you could get your intake number easier. The numbers I gave are just kind of a general number for most saws above 70cc. Specific models like different numbers though and with an aftermarket cylinder you never know. Maybe @huskihl will swing by and correct me.

Nope I think you’re pretty close. Maybe 78 on the intake so if any machine work was ever done in the future the intake height would still be kinda acceptable

 

[drf255]

Really gotta measure with a ring and pick to be accurate on the ex and trans. A visual measurement will certainly be off and vary from user to user as well as cylinder to cylinder. Visual gets you in the ball park, but I have personally been off more than 5 on exhaust and over 10* on the transfers going visual. Intake skirt is usually accurate and you are stuck that way unless you use a port height software program and a depth mic.

Two ways of measuring, port opening degree or total port duration. For opening degree (what I use), you need to find TDC first by either using a piston stop or marking your wheel where the intake skirt opens and closes and then splitting the difference on the wheel.

Duration is tricky. For the intake, the opening and closing point x 2 is duration. For the exhaust and transfers, it’s 360*-open degrees/2. So if your exhaust roof is open for 160*, it’s 360-160/2=100* opening point. Because your visual should be close to the same up and down, the duration method should get you closer visually to the truth, but I still prefer the ring and pick method because that’s how you’ll be marking your port heights for grinding anyway.

Another note, there is no before or after TDC on a 2 stroke, it’s all one in the same. A piston ported 2 stroke can actually run in reverse if started that way.

 

[drf255]

One more thing, and hate to rain on your parade, but try to source an oem cylinder if you want the best performance.

Been through this many many times. There will always be something missing in an AM cylinder no matter how you slice it. It’s generally in the transfer tunnels and shape/direction. Even The best porters around can’t make a silk purse out of a sows ear. We have done buildoffs’ s with countless hours of work put into AM cylinders only to be beat by OEM cylinders with little to no work.

Hyway and meteor have very good plating. Meteor has plating that I’d stronger and thicker than oem in most cases. The stuff is like a rock. I would bet that your upper and lower transfers have an intake side edge that are in line with each other vertically. If you take a peek at an oem, I’ll guarantee that the entire upper is further over towards the intake side vs the lower intake side edge.

 

[drf255]

Here are 2 ms260 jug transfers. See the difference?

Mahle


Meteor

 

[Yotaismygame]

From what I've seen this series of saws like a lower exhaust and higher intake than most. But with that said the first one I did had an exhaust at 98 and it ran good. It was a fallers saw and he really liked it. I've done 460s with the intake at 77 and exhaust at 104 and it was a screamer. I have a oem 460 cylinder I would part with. Needs a little transfer removed..