Help With Port Timing

[CHEVYTOWN13]

CHEVYTOWN13 walks back into the AS Saloon with his pist off hog after spending a night in jail and looks for the sherrif. He's surrounded by 10 chicks..."Brother D, I have to talk to you! Thanks Dave."

Masters, can you please help with port timing? Any threads that come to mind please post.

I posted pics of the port work and then the piston in it.

I realize now it is "hogwash," I went "hog wild," I was "hogging it" etc. I created a free port? at the bottom of the port. I should have cooled it then, but added too much salt and messed things up.

Wide next time...I get it.

http://web.mac.com/bluemetal/Blue_Metal_Studio/CAD.html

Much obliged sir...

 

[Metals406]

Stock port...

Went hog wild on the port... Realized it was too much too late.

TDC, slight freeport...

BTC, ring isn't in the port area...

Piston still seals port mid stroke...

Hope this helps... Now people can view in the thread instead of through the link.

 

[volks-man]

whats the problem?
i thought a little freeport could be 'snuck by'.
did you run it?

 

[Metals406]

I agree with the slight freeporting... I think he wants some help with timing numbers...

 

[Erick]

Well...... nobody ever said getting an education was cheap.

 

[CHEVYTOWN13]

Sup fellas...

Here is the link to the movie where I ran it trying to tune it. I have fiber optics and it took 3 minutes to load. Sorry, I can't compress the movie anymore. Begin download and grab a cerveza

http://web.mac.com/bluemetal/Blue_Metal_Studio/CAD.html#11

Does freeport act/work like a ventilation system for example like on a crankcase needing ventilation through the oil breather? Just guessing...

Going to sound weird, but I leaned out the saw all the way(going to double check because it was by ear and not tack) and I think it still has some potential maybe in the form of an adjustment on the flywheel since I changed the port map?

3 parts to the movie. 3/8-16" Carlton chain half baked after some cutting mostly pine, and some oak. Greenhorn tuner to boot too. I still can't believe I got the saw back together again AND running!!!

1st part. Had muffmod on and it did not run well at all. It seemed like it needed more backpressure with the opening of the port.

2nd part. Stock muffler on and ran much much better. I began to feel the engine rocking in it's cradle. First half of cut I'm pushing and then second half of cut I'm letting the saw do all the work. Tuned diff than the 1st part.

3rd part. It's starting to come alive. I cut a piece of gnarly pine that was sitting in the ANGELES NATIONAL FOREST for some years I think. I don't think anyone was crazy enough to try it, but I had to carry this piece about 25 yards up a steep slope. But new it would make a good hard cutting piece for tuning and the like(same piece used for all 3 cuts). Tuned diff than the 2nd part. I'm pushing very hard and couldn't get it to bog, but I heard an RPM change and constant thereafter.

I hope I can swap out the ignition module for the 510 and can put on a module from a 5100 to try and gain 1000k's. Possibly 600 usable rpm's under load? I don't know. But it would help I think.

It does feel stronger than stock. Possibly modify the stock muffler with just taking out the heat deflector. And keeping the hole stock or opening it a little bit, but not by much. Just guessing here and experimenting...

 

[Metals406]

If you don't have a degree wheel... Here's one. Print it off, and glue or tape it to an old CD.

Pull the exhaust, and degree your port timing... Then you'll have numbers to get feedback on.

I have to say, I'm curious what you ended up with on your exhaust.

 

[CHEVYTOWN13]

The Doctor To The Rescue!

Thanks Metals406. I'm going to size it for a CD and print that out.

I'll have to research and learn before I can mess with it CUZ I HAVE NO IDEA WHAT I'M DOING.

Off to the research room...

 

[CHEVYTOWN13]

Schooling is tough

Well...... nobody ever said getting an education was cheap.

CHEAP! Bro, the school of hard knocks

 

[parrisw]

If you don't have a degree wheel... Here's one. Print it off, and glue or tape it to an old CD.

Pull the exhaust, and degree your port timing... Then you'll have numbers to get feedback on.

I have to say, I'm curious what you ended up with on your exhaust.

How do you use a degree wheel on a saw. Put on flywheel I take it, then do you set to TDC with a dial indacator or something, then adjust the wheel to 0?

 

[teacherman]

Good luck getting the port timing figured out. This type of thing is way above my pay grade, so to speak. A slight muff mod and a sharp chain are a pretty decent combo.

I got to run a Jonsered 2077 today. Nice saw. I like the sound, kind of old school.

 

[CHEVYTOWN13]

Hey John.

I've been wanting to learn how to do it. It's a must. I could see the port #'s changing. It was a radical hogging of the port.

It was a great feeling actually doing it with hand tools. I felt "one with the port" and not from a distance. It brought back a rush I haven't felt in years...

I still have to mess with the idle. It was running high at the end of the video and I stopped there. I will be use the tach tomorrow and tinkering with it before I do the muff mod on it.

BTW, again, your art work is bomb bro. Awesome work with the router for the address.

 

[CHEVYTOWN13]

If you don't have a degree wheel... Here's one. Print it off, and glue or tape it to an old CD.

Pull the exhaust, and degree your port timing... Then you'll have numbers to get feedback on.

I have to say, I'm curious what you ended up with on your exhaust.

Bro, I'm taking this to a shirt place and have them put one on a white shirt. Would be cool to see it on a shirt...

 

[CHEVYTOWN13]

I was wondering...

How do you use a degree wheel on a saw. Put on flywheel I take it, then do you set to TDC with a dial indacator or something, then adjust the wheel to 0?

Can we use the magneto to set TDC and then place degree wheel? I read other posts that talk about putting a feeler gauge/stop of some kind into the plug hole to read TDC or using a timing gun?

The timing gun sounds like a good idea paired with Metals' degree wheel.

Off to the LA BO RA TO RY....UUUUUUGHGHWWAAAAAAAAA!

 

[Metals406]

The degree wheel to CD trick has floated around for a while... Not sure who came up with it?

From TW: "99.9% of the time on 2 stroke motors the number you get in deg ATDC (after TDC) when the port opens must be the same as the number of deg BTDC (Before TDC) when the port closes. If it doesn't = the same value you have not found TDC correctly."

From four paws: Use a piston stop to find TDC. Rotate CW until piston hits stop - record number. Rotate CCW until piston hits stop - record number. Determine the duration between the two measurements - the center of this duration is TDC - center your wheel here.

From TW: To set the degree wheel, try placing a fealer gauge in the exhaust port, then move the piston to both extreams, it should be the same number of degrees to opening after TDC as it would be to Before TDC on closing.

Once you have TDC dead on best recheck all the numbers.

I have tried approximating TDC and can get close by watching the piston through the exhaust port and centering it in the zone of least motion at TDC, but still it is easy to be off a couple degrees.

If you have dropped the jug by removing the gasket, but have not raised the exhaust or transfers, you likely will have lots of low end torque, but it may do much at higher RPM.

Also: http://www.arboristsite.com/showthread.php?t=80321&highlight=Degree+Wheel

http://www.arboristsite.com/showthread.php?t=79554&highlight=Degree+Wheel

 

[Metals406]

Andy's thread on degreeing a saw: http://www.arboristsite.com/showthread.php?t=40826&highlight=Degree+Wheel

 

[CHEVYTOWN13]

Magnet on flywheel/ignition module

Metals, do you know what type of magnet is on the flywheel? I just put a tool to it and it zipped right to it! I'm guessing some type of rare earth magnet. Maybe I can use that to polarize the magneto set-up (for lack of the correct term) for a quick ALMOST TDC.

Take muffler off, look at piston as it goes on the upstroke. Let it settle up top when it "jumps the hump," which means it's beginning it's down stroke now. And play with the flywheel and magneto within that small range? Super close to TDC and then use TW's method to hopefully end up with the 99.9% of knowing you are on TDC...

Just taking wild swings on a 0-2 count!!!

 

[troutfisher]

You don't need to find TDC. Just measure the total duration that the port is open.

 

[CHEVYTOWN13]

You don't need to find TDC. Just measure the total duration that the port is open.

Now things are starting to make sense

 

[parrisw]

You don't need to find TDC. Just measure the total duration that the port is open.

Care to elaborite? Say I want to drop the jug, so I take a reading with the stock setup, measure the time the port is open, then take the gasket out, measure again, and the difference is what I want to make up, so How do I turn degrees into how much I need to raise the exhaust?