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

[dieselfitter]

I know Adam knows what a D handle is, put one on there, it hurts less, coarse that might spoil the image.

That has been discussed. It's definately a "two hander" to start. The rope pulled through the knot after a few pulls last night. We had to remove the recoil and re-tie it.

 

[Dub11]

That has been discussed. It's definately a "two hander" to start. The rope pulled through the knot after a few pulls last night. We had to remove the recoil and re-tie it.

Use a cable lol. Just watched your shop tour video. Wow!!!!!!

 

[dieselfitter]

Use a cable lol. Just watched your shop tour video. Wow!!!!!!

Thanks Wayne. If you're ever up this way, I'd be honored if your stopped in to visit. I'm sure we'd find something to talk about.
Tim

 

[dieselfitter]

I worked on mounting the covers today. In previous posts, they were just sitting on the saw.



These aren't the covers I'm planning on using, After I've run it a bit, I'll mount the final covers. These were helpful in determining what had to be removed and what didn't need to be removed. I cut a bit more than needed when I was trying to fit the tillotson HL carb that was too big. That bracket on the carb was time consuming. When I find time, I'm going to make something to cover the gap created by raising the cylinder cover 3/4".

 

[Chris Zautner]

Everything I see about this build is quality and attention to detail. Very well done sir.

 

[dieselfitter]

Everything I see about this build is quality and attention to detail. Very well done sir.

Thanks Chris and many others for your kind words.
Cylinder arrived today. Adam is stopping over to help tomorrow...

 

[loco]

I'm simply in awe. This is my type of project man and I for one thank you for posting it. Can't wait to see that thing munching trees. If it's not too late for the naming ceremony, my vote goes for the g.o.a.t. the greatest of all time and oddly enough I think that saw will eat anything. So it's fitting.

 

[Yukon Stihl]

I worked on mounting the covers today. In previous posts, they were just sitting on the saw.
View attachment 48172
View attachment 48173
View attachment 48174
These aren't the covers I'm planning on using, After I've run it a bit, I'll mount the final covers. These were helpful in determining what had to be removed and what didn't need to be removed. I cut a bit more than needed when I was trying to fit the tillotson HL carb that was too big. That bracket on the carb was time consuming. When I find time, I'm going to make something to cover the gap created by raising the cylinder cover 3/4".

How about some black rubber like on the winter covers for Stihls...
or cut the bottom part off of a cover and weld it onto the bottom of the final cover,sand and paint.

 

[dieselfitter]

Did I mention the fact it is getting a cylinder head. I didn't find out until Adam told me today.

It's be a semi-toroidal chamber. Kinda like a slice of a doughnut. Done for the day. Back at it tomorrow.

 

[Deets066]

Did I mention the fact it is getting a cylinder head. I didn't find out until Adam told me today.
View attachment 48477 View attachment 48478
It's be a semi-toroidal chamber. Kinda like a slice of a doughnut. Done for the day. Back at it tomorrow.

That's gunna be a sweet saw!
Good idea with the head, be good not to overdue it on compression so your little recoil can keep up

 

[drf256]

Simply amazing. I'm at a loss for words.

If you'd like the original cracked handle repaired, send it my way.

 

[dieselfitter]

Adam and I went on a road trip yesterday to visit dome saw shops.
I picked up some fresh meat for the grinder. The Red Craftsman is a 3700. It looks like it has seen very little use.
We didn't get back and start work on the stroker until 8:00pm.
The cylinder bore has damage from a piston ring at the top of the bore. It is usable if we raise the cylinder. The cylinder is raised to the extent that we want a cylinder head to maintain compression. I started with a 1" plate of aluminum.

I centered up my rotory table...

 

[dieselfitter]

Plunge and rotate with a ball end mill.
I found an O ring for a head gasket from my assortment of left overs from my transmission rebuilding days.

It's not done, the center will be cut down to raise spark plug electrode location. The other side needs some finish work.

It isn't gonna see wood this weekend. Still a lot more to do.

 

[dieselfitter]

Simply amazing. I'm at a loss for words.

If you'd like the original cracked handle repaired, send it my way.

Thanks for the kind words and offer. I had been looking for a handle for some time. I recently got a few parts saws and have a good right side to combine with a good left.

 

[tree monkey]

what kind of comp ratio you going with?

 

[dieselfitter]

Not sure what it is. I was originally wanting a high ratio but after more thought, I'm thinking that might not be a good idea.
Correct me if I'm wrong, I understand raising compression to provide diminishing returns, more so on larger bores. I'm thinking a high ratio will put more strain on the crankshaft, more than necessary to see gains. I haven't measured the volume difference in combustion chambers, I still have material to remove from the new one. I would guess they will be close in volume when the new one is complete.
Scott, what are your thoughts?

 

[dieselfitter]

I'm planning on cutting the center spark plug height to the scribed mark. That will place the point of ignition in the center of the combustion chamber. The squish band has a slight slope.

 

[dieselfitter]

Adam has been grinding.


I cut the cylinder skirt. Adam will connect the ports.

Here is the damaged bore. After raising the cylinder, the ring won't ride up into the damaged area. Port timing is looking good according to Adam. He told me the numbers but I don't remember them.

 

[dieselfitter]

Adam signed off on the proposed plug height. I ordered head bolts from McMaster Carr. They should arrive Tuesday. With the possible exception of cooling fins and cosmetic work, the head is done.

 

[Frank bierce]

This is an awesome thread...freakin love it. I know if I was doing this...I'd find a whole lot of ways NOT to do it!! Lol.