Poulan 3400,3700,3800, 4000 stroked crankshaft project. Part 2

[Derf]

Sure would be nice to see you throw a 28" bar on there and bury it to see what kind of power it makes.

 

[Jonsered_raket]

Sure would be nice to see you throw a 28" bar on there and bury it to see what kind of power it makes.

In time it will, these are the first cuts of a year+ long project. Still things to change yet and saw needs some run time to "settle in". I'm amazed it runs as good as it does. Friday we are going to get some clean wood and nail down a tune, saw is still plenty rich. I think it will get a lot of attention at gtgs. This saw wasn't built for work.

 

[Deets066]

Looks pretty good!

Where is at with rpm

 

[Jonsered_raket]

No idea, didn't have a tach. This was just a "too anxious to wait for proper weather and tune" run. We'll get some stuff dialed in and turned up this weekend.

 

[dieselfitter]

40% more better.

 

[Red97]

How did it "feel" vibe wise?

Just wondering if anything felt "odd"

This build is awesome. Can't wait to see further tests

 

[dieselfitter]

How did it "feel" vibe wise?

Just wondering if anything felt "odd"

This build is awesome. Can't wait to see further tests

Vibration wise, just as smooth as any other saw. Only thing that seems like it might be off is ignition timing.

 

[Jonsered_raket]

Felt great, no vibes. Tim did an amazing job balancing that insanity.

 

[Deets066]

Let's talk about porting, where did all of that come out?

 

[dieselfitter]

Let's talk about porting, where did all of that come out?

Adam posted the numbers a page or two back.

 

[Deets066]

Adam posted the numbers a page or two back.

Oh, I thought those were where it timed before porting

 

[Jonsered_raket]

I'll post numbers once it's done, can't remember off top of my head. I know exhaust was 100 and blowdown was 19.5 I believe. This is basically our baseline run.

 

[Jonsered_raket]

Tim needs a saw that's forgiving. We will find where it makes its power, rpm is what it is at that point. If it spins 13000 and makes its power I'd rather have that then 16000 and a slouch. All saws react differently, no way to tell what 4 saws combined will like.

 

[dieselfitter]

Adam and I took Friday off from working on this project. The oiler isn't oiling and the cylinder head needs work. I will check into having the cylinder e-plated. It is worn through the chrome at the top where the ring stops and it is also flaking below the exhaust port. I have some other matters to attend to. I may take some time off from this project. When completed, I'll post another video.

The cylinder head was a rushed job. I screwed up and drilled holes in the wrong pattern. The quick fix didn't hold up. I didn't like the design anyway. Semi-toroidal is something borrowed from a diesel engine, probably not suitable for a 2 stroke spark ignition engine.

 

[mdavlee]

Us chrome or millennium will fix you up on the plating

 

[Dub11]

Adam and I took Friday off from working on this project. The oiler isn't oiling and the cylinder head needs work. I will check into having the cylinder e-plated. It is worn through the chrome at the top where the ring stops and it is also flaking below the exhaust port. I have some other matters to attend to. I may take some time off from this project. When completed, I'll post another video.

The cylinder head was a rushed job. I screwed up and drilled holes in the wrong pattern. The quick fix didn't hold up. I didn't like the design anyway. Semi-toroidal is something borrowed from a diesel engine, probably not suitable for a 2 stroke spark ignition engine.
View attachment 49766
View attachment 49767

Well now my life is on hold

 

[dieselfitter]

Us chrome or millennium will fix you up on the plating

Thanks Mike.

 

[mdavlee]

Thanks Mike.

Us chrome is in Wisconsin.

 

[rocketnorton]

id suggest copper wire rather than oring for head gasket/fire ring.
+ iron/steel sleeve.
lotta work, tim, but yer showin yer not allergic to that.
easy for me to say from here...

 

[DSS]

Smooth yet aggressive