2159 new AM cyl 100psi

[davidwyby]

I am interested in hearing what you think of the 357 top end and how it compares to the 359.

If I get the 359 top end running good, LMK if you're interested in it to get yours going. Might keep it for a spare, but let me know.

 

[p61 western]

Did I say something wrong? Y'all don't like Californians? We're not all the same, you know... ;-)

Nope we are all libitards out here lmao.

 

[Marshy]

I don't have first hand experience with it, I'm just along for the ride. The plug looked like you were on the right track, still a little rich.

 

[davidwyby]

I dunno man, no 4 stroke makes me nervous! I'm on the bleeding edge now.

I wanna get the RPM up a little...upper xfers up/open maybe? Raising exh loses comp...

 

[davidwyby]

Current plan, not fully numbered out yet. Been collecting recipes for the 359 and 357 ;-)

I'm planning to machine to squish band a bit because there is a little ring around the outside .010" tall x about 1/8" wide (see pic of solder squish test) which is limiting my "true" squish. I want to get rid of it and get the "roof" flat to increase compression. Then machine the base a hair more to get squish to .018"-.020". Then I will have to go ahead and raise intake. I'm seeing a trend while researching of recommendations to not go over 80* on the intake port. Probably 120-122* upper transfers and widen a little. Going to have to measure and map it all out, I may be getting close to freeporting with the exhuast port at that point.

 

[Marshy]

Careful about taking too much off the base. You can lower the exhaust floor too much and cause it to free port.

 

[huskihl]

You probably should have tried running it while it still had the lowers in the 357 location. I believe hogging them out so it looked like a 359 is possibly what's limiting your RPM

 

[davidwyby]

You probably should have tried running it while it still had the lowers in the 357 location. I believe hogging them out so it looked like a 359 is possibly what's limiting your RPM

I'm a little confused. I'm still messing with the AM 359 cyl. I hogged it out to rounded edge lowers to the gasket like a 357. It's together, running decent 4 stroking at 12,500. I think I get what you're saying about taking too much out of the lowers while the uppers are still small and potentially stalling the airflow.

Not going to mess with the 357 yet, and only very carefully. ;-)

 

[Marshy]

You probably should have tried running it while it still had the lowers in the 357 location. I believe hogging them out so it looked like a 359 is possibly what's limiting your RPM

Only cylinder he's modified so far has been the AM 359 cylinder.

 

[huskihl]

Only cylinder he's modified so far has been the AM 359 cylinder.

Thought it was a 357bb? 357 lowers with 359 bore

 

[huskihl]

Only cylinder he's modified so far has been the AM 359 cylinder.

Thought it was a 357bb? 357 lowers with 359 bore

Muh baaaad. I see now. Regular AM 359

 

[Marshy]

Thought it was a 357bb? 357 lowers with 359 bore

http://ahlbornequipment.com/search.aspx?find=359+cylinder

 

[davidwyby]

Wow. Time flies. We moved and everything got stuffed away. Recently dug stuff back out and started putting the 2139 back together. It’s still giving me fits. I decided I wanted the 2159 ported to compare to the MMWS Dolmar 6100 and then sell one, and I didn’t want to fuss with another saw, so I sent the 2159 with both the aftermarket PnC that I didn’t quite finish porting and the 357 PnC to @Benwa . We shall see!

 

[davidwyby]

 

[Benwa]

3 years after the original post..........

 

[davidwyby]

@Spike60 We finally put that 357 PnC you sold me to work.

 

[Spike60]

Looking good! How long ago was that?

 

[davidwyby]

Looking good! How long ago was that?

March '18. It got hot and then I got into other things and then I moved...and then Ben made a monster, haha.

 

[davidwyby]

Little side trail…melty oil worm, hijacked a thread. Wanted to keep the story on this saw in one place if for no other reason than so I can find what I did when later.

https://opeforum.com/threads/325-pitch-on-357.6942/#post-1376478

I put the new worm in and ran it tonight. Didn’t idle or part throttle right…gas was old so I changed it…and took the clutch assy off too. Still didn’t run right with fresh gas. Gave it a spray of brake cleaner while running on the crank seal and it died…guess the worm messed up the seal when it melted.

 

[davidwyby]

Old one from years ago on the right…good AM one from my 359 in the middle…recent melter on the left.

I noticed the grind marks on the screw head in front of the crank…I assume that’s from the .325 9 pin rim. Oops. Maybe it melted the worm and then it failed the rest of the way after I swapped back to 3/8”.