576 non-AT project

[meglodon]

I have acquired a couple 576 projects off ebay, (autotune on the right w/the full brake handle, non-AT on the left) These saws don't get much love on the forums, but for the price I couldn't resist the projects.


The autotune saw had a fuel line issue and once I did some cleaning. The piston on it looks super clean and with the new line, I was able to get it up and running with out any issue. Have a buddy who wants it so ordered a full wrap for it and its ready for testing and then we'll send that down the road.

But this thread is about the Non-Autotune Project and my path to learning how to use a timing wheel and port.

The non-AT 576 had a scored piston as well as transfer that was all over the cylinder.



But, a bit of elbow grease, some emory cloth and I was able to remove the transfer and the cylinder looked (to me) to be ok, I couldn't feel the line that's in the pic here


So, with some addtional work continued to work on removing the transfer off the cylinder walls.

I figured it'd be a good 'learn to see if it can be done' thing so I I picked up a hyway piston to learn how to use a timing wheel, do some mild porting and run with no base gasket (once I checked squish)

 

[meglodon]

As I have been doing a bit or research here, on youtube and other areas, I read good things about the Hyway pistons and figured I'd give one a shot.



It seems to be a exact copy of the oem one from a dimentional standpoint fit into the cylinder with minimal slop and I was able to check the timing with my timing wheel.







The numbers I had without the base gasket were:
Squish: 0.020
exhaust: 106 open after top dead center
transfers: 126 open after top dead center
intake: 76 degrees

I decided I was going to shoot for 100 on the exhaust and see if the saw runs. I'm still learning and decided that would be a decent number to shoot for and test. I also did some work on the transfers to knife edge some of the opening and work to streamline the flow into them.

 

[meglodon]

and... sadly it appears I just lost the the reply I spent a bunch of time writing

short version: I watched some of the Iron Horse youtube videos where he talks about the benifits of heat treating your piston so I gave it a shot
450 degrees for four hours (with a old wrist pin in it) then quench in ice water.


It changed the color to a dark dull gray and highlighted the fine grain sandpaper scratches (but you can't feel it with your fingers/finger nail.)

put things together with 1184 (Thanks for the tip on that @weimedog)


after rounding up a few more parts that were missing when I got it it was looking like this when I fired it up.

 

[meglodon]

Spent some time heat cycling it and ran three tanks through it with interspursed blipping of the throttle to get anything that pooled up out of the system. I was able to source another muffler (the one I had for it was dented in pretty good)

I'm in grad school so don't have time to get out to the woods and test things out (hopefully soon)

I had a nagging suspicion I put things together but didn't check the final orientation of my circlips so I decided to pull the cylinder to confirm and see what the piston wear was like (I had put my circlips in at the wrong orientation where they probably would have come loose if I got on the throttle hard... hey... I am still learning.) Also, I have watched lots of vids where of people say to clip the clips, but I am curious to see how this holds up stock (so to speak)

Clip after being adjusted:



Overall the piston has some wear I think but I also am curious to see how things look once I get some more time with a bar and chain on it. This is an experiment for me to learn and see how things hold up.



More to come as testing continues.

Another note: I was using sthil ultra full synthetic (50:1)

I have been doing a lot of reading around mix ratios and based on some videos out there have decided to test out some other stuff. (I don't want to turn this into a fuel mix ratio war, but I'm I am curious to see what occurs wear wise as I change to different fuel mix manufacture and ratio.

 

[mbrick]

Nice project. How are your squish numbers with no gasket and 1184?

I should port (or find someone who can) port my 576.

 

[Maintenance supervisor]

Whats your graduate study in?

 

[J D]

We'll done with your builds.
To get any meaningful indication of wear associated with an oil you will have to use it for a loooooong time (or use less than than the required amount for a short time & sacrifice your equipment)
On a fresh build I'd be inclined to tune it a bit rich, & run a bit more oil (preferably something other than Stihl ultra)

 

[meglodon]

Nice project. How are your squish numbers with no gasket and 1184?

I should port (or find someone who can) port my 576.

Thanks! Good question, I'll have to check when I get a chance to get away from my keyboard. (from what I've read sealent will add a thousanth or two to the squish) when I get a chance to do that I'll update with some info!

Whats your graduate study in?

Enterprise Architecture and Business Transformation through Penns State's world campus (it's an online course, but I'll graduate w/a Penn State Degree) I'm on the last semster and I'm looking forward to getting more time away from the computer!

We'll done with your builds.
To get any meaningful indication of wear associated with an oil you will have to use it for a loooooong time (or use less than than the required amount for a short time & sacrifice your equipment)
On a fresh build I'd be inclined to tune it a bit rich, & run a bit more oil (preferably something other than Stihl ultra)

Thanks! Yeah, I would rather not sacrifice by mistake and watching videos/reading some reviews see that there is other (most likely better) options than the Sthil Ultra. (I used to work on at sthil dealer as my first job learning to wrench of small engines before the internet was a thing, have been running their stuff from old habits I guess.)

 

[Maintenance supervisor]

Thanks! Good question, I'll have to check when I get a chance to get away from my keyboard. (from what I've read sealent will add a thousanth or two to the squish) when I get a chance to do that I'll update with some info!

Enterprise Architecture and Business Transformation through Penns State's world campus (it's an online course, but I'll graduate w/a Penn State Degree) I'm on the last semster and I'm looking forward to getting more time away from the computer!

Thanks! Yeah, I would rather not sacrifice by mistake and watching videos/reading some reviews see that there is other (most likely better) options than the Sthil Ultra. (I used to work on at sthil dealer as my first job learning to wrench of small engines before the internet was a thing, have been running their stuff from old habits I guess.)

My mom taught for Penn State for 23yrs , she did some of the pilot classes for the online world campus.

 

[meglodon]

checked the squish today, looks like we're in the 0.0225 (ish) range