Craftsman 3.7 rebuild! Lots of pics! Update, 11/24/2016 finished!!!

[ANewSawyer]

So it is Saturday night. What is a single guy supposed to do but rebuild chainsaws?! I got this saw from a dear friend of mine named Jim. I only really got to know him for a year before he passed. But he opened the door for me to become a wood carver, and I have now started taking prizes for some of my woodcarvings. But, back to the topic at hand, chainsaws. I have had this saw for a little over a year, see the original thread here: http://www.arboristsite.com/communi...ut-this-old-craftsman-saw-pic-warning.279053/

So I have been wanting to do a really good rebuild and this saw justice, for my friend. First things first, it is FILTHY!



I had actually cleaned it a little just to get it this far apart. Sat down with a bucket of soapy water, a cheap paint brush and a bathroom bristle brush.


Much better!!! I also cleaned the old base gasket off the cylinder base. I am hoping to measure the squish as I reassemble with a view toward sanding the base. No lathe but some sandpaper and a plate of glass should get it.
Pics of cylinder. Not sure what is up with the polished areas.
.
@backhoelover @HarleyT

I just can't get over how much better it looks. I am going to replace the oiler gasket but the old one broke in two piece when I was trying to remove it. That will be a slight challenge

 

[Efisher26]

I just asked this a new thread but since u brought it up on the saw I have, what is squish? Deleting the base gasket and the can sits lower correct?whats that do mechanically?


-Efisher26-

 

[ANewSawyer]

Squish is the distance between the top of the piston and the bottom of the combustion chamber or squish band. It is one of many factors deciding your compression. Delete the base gasket and the cylinder sits lower, possible retarding timing slightly but increasing compression. Sanding the base of the cylinder helps to achieve the target squish, usually around 0.020. I have to measure my squish first before I can delete the base gasket.

 

[ANewSawyer]

Should have split the case when the first seal hung and bit the case. Like an idiot, I didn't. So now I get to split the case and order another seal cause I used two. Both deformed and bit the case. Dang tricky to install. @Modifiedmark was right.

 

[Modifiedmark]

They are a bit challenging, but if your careful and pay attention there not all that bad compared to some. I know you seen the pictures I posted before on putting a bevel on the case with a round stone in a drill if the case is split. I know I have also shown how I can take a pocket knife and cut a bevel on it if the case still has the crank in it. You also need a correct size driver for it and a seal protector to slip on the crank when putting the seal in.

You think these are tricky, you ought to try to put seals in some of the old sandcast saws, those are really tiny and the PTO side uses two of them. Pulling them is the real challenge..

 

[Modifiedmark]

I found the picture of the bevel on the case.. Like I said, you can do it with the crank in if needed and really helps get them started

 

[ANewSawyer]

Thanks. Trying to get them to start not crooked is hard. I am new to mechainical stuff like this. I seem to have a small knaack for it but I cannot figure out where I got it. I don't know of anyone else in my family tree mechainally inclined.

Do you think I have messed up the case seal trying to pull it apart? I am thinking not because it isn't apart yet. I am not even sure I was able to budge it. Maybe just slightly. Thanks Mark. I made a protector out of an old piece of a hand soap pump. It doesn't fit over the lower step but goes right up to it. Leaves just a small height difference. I have to push the seal just a bit to get it over the step. Also took a couple of bites out of the case with the deformed seals. No burr on the inside of the seal surface though.

 

[ANewSawyer]

Drat, I have been using a deep wall socket to drive the seals. That is not going to work is it?

 

[Efisher26]

I use sockets or pvc pipe


-•------------------------------------------------------------


Just a home owner that likes the older better made machines

Craftsman 3.7
Echo 290evl

 

[Modifiedmark]

Drat, I have been using a deep wall socket to drive the seals. That is not going to work is it?

Thats mostly what I use. You just have to make sure you get the size matched up close. Patience is needed in getting them started.

 

[Modifiedmark]

Also took a couple of bites out of the case with the deformed seals. No burr on the inside of the seal surface though.

If you look at the picture I posted, you can see I used some MotoSeal around the seal, its cheap insurance in case there is a nick in the case to make sure it seals well.

 

[redunshee]

If you look at the picture I posted, you can see I used some MotoSeal around the seal, its cheap insurance in case there is a nick in the case to make sure it seals well.

Dang. Where you been buddy?

 

[Modifiedmark]

Dang. Where you been buddy?

Busy, real busy.

 

[ANewSawyer]

It is finished! Split case and resealed. Base gasket delete, dremeled the intake block and a muffler mod, drilled the internal deflector out and louvered the muffler. Sharp chain too. The fourth picture is the saw ready to be vac/pressure tested and the fifth and sixth are off the new motoseal on the case.

 

[redunshee]

It is finished! Split case and resealed. Base gasket delete, dremeled the intake block and a muffler mod, drilled the internal deflector out and louvered the muffler. Sharp chain too. The fourth picture is the saw ready to be vac/pressure tested and the fifth and sixth are off the new motoseal on the case.

Looks real good. Should be real strong.

 

[Efisher26]

What's the compression ANewSawyer?


Sent from my iPhone using Tapatalk

 

[redunshee]

What's the compression ANewSawyer?


Sent from my iPhone using Tapatalk

I'm assuming the saw is a 3700 clone and not a 3800. New rings w/o run time I'd expect at least 145, maybe more. Higher after rings seat.

 

[Efisher26]

The only 3800 I've ever seen had poulan colors and said 3800, I'd assume yours is a "craftsman 3.7" like mine


Sent from my iPhone using Tapatalk

 

[redunshee]

The only 3800 I've ever seen had poulan colors and said 3800, I'd assume yours is a "craftsman 3.7" like mine


Sent from my iPhone using Tapatalk

Some of the 3700 Craftsman labeled as 3700 had 3800 pistons and cylinders. I had one and believe it was a PowerSharp.

 

[redunshee]

Some of the Craftsman labeled as 3700 had 3800 pistons and cylinders. I had one and believe it was a PowerSharp.