WSC 038 Mag build....

jacob j.

When I let my hair down, my friends call me Dick C
Jan 9, 2012
8,421
68,757
113
Hoggin' it out is what this country's all about.
 
  • Like
Reactions: 2 people

thomas1

┌∩┐(◣_◢)┌∩┐
Staff member
Oct 22, 2012
28,170
206,763
113
Fredericksburg, Va
At least he didn't put blue goo all over it and try to blame it on some poor, unsuspecting kid from Colorado this time.

:farkyou:

Wanna share the guilty party's location?
 
  • Like
Reactions: 3 people

jacob j.

When I let my hair down, my friends call me Dick C
Jan 9, 2012
8,421
68,757
113
IIRC, it's a long gone AS member. I'm not real sure where they were from.
That reminds me of a guy- long ago, on a build-off; who decided to drill a hole through the top of the cylinder and insert a giant bolt and nut to raise compression.

lulz.
 
  • Like
Reactions: 3 people
Exhaust - 101
Transfers - 119 ----- .
Intake 78

Those are about stock numbers more or less .Except as I recall the transfers are at around 20 after the exhaust .

If I remember right the stock piston to head deck clearance is around 45-46 thou which does better at around 23-26 thou .The exhaust set at 96 would give you a little more blow down which you'll need at higher speeds ,Depends on what you have in mind I suppose .

I'm not sure what to do using a flat top but with a pop up the uppers mildly fingered will give you a better sweep ,really makes a difference .Neat older saw model,my favorite of all the Stihls .If they are done right they will scoot .
 
  • Like
Reactions: 3 people

Wigglesworth

autotune gives me a pop-up
Jan 9, 2012
1,604
2,753
0
38
West Kentucky
Exhaust - 101
Transfers - 119 ----- .
Intake 78

Those are about stock numbers more or less .Except as I recall the transfers are at around 20 after the exhaust .

If I remember right the stock piston to head deck clearance is around 45-46 thou which does better at around 23-26 thou .The exhaust set at 96 would give you a little more blow down which you'll need at higher speeds ,Depends on what you have in mind I suppose .

I'm not sure what to do using a flat top but with a pop up the uppers mildly fingered will give you a better sweep ,really makes a difference .Neat older saw model,my favorite of all the Stihls .If they are done right they will scoot .
Here is the main reason I'm using an 064 piston...



The windows are significantly larger, which will "hopefully" promote better flow thru the lowers.

As for the stock numbers, with .040 out of the squish band, using th 064 piston they were

Exhaust. - 105
Transfers - 123/124
Intake - 67

Of course that's with a real long skirt, due to the 064 being 40mm stroke over the 038's 36mm stroke, so it would had been significantly lower intake with the OEM piston. I just cut the skirt to length on the 64 slug to set the intake. The pin to crown height was nearly .030 taller on the 064 slug as well. Should make all kinds of compression, hopefully not too much though. Easy fix if so, I'll raise the exhaust a bit.

I'm just looking to make a real nice strong work saw, no racer. In my meager findings, the two transfer jugs like less blowdown than the bottom fed type cylinders. I've been wrong before though....
 
  • Like
Reactions: 2 people
To tell the truth I never gave using an 064 piston any thought but it sounds like an idea .I opened the windows up on the stock Mahle 038 Mag piston though .

What the hey if you can hold the speed up using a short transfer and a long exhaust you've got a winner .In my case with a domed popup I had to put a D-handle on it because it became a finger snapper .

I'm curious as to how this works out because I've got another 38 mag in the shed I haven't even started on yet.Lots of saws ,no time .
 
  • Like
Reactions: 1 person

Wigglesworth

autotune gives me a pop-up
Jan 9, 2012
1,604
2,753
0
38
West Kentucky
To tell the truth I never gave using an 064 piston any thought but it sounds like an idea .I opened the windows up on the stock Mahle 038 Mag piston though .

What the hey if you can hold the speed up using a short transfer and a long exhaust you've got a winner .In my case with a domed popup I had to put a D-handle on it because it became a finger snapper .

I'm curious as to how this works out because I've got another 38 mag in the shed I haven't even started on yet.Lots of saws ,no time .
I am a bit worried compression might be a wee bit much, but like I mentioned, a little added exhaust duration, or a thin gasket will help on that.

I've had real good luck with the two port stihls running a bit shorter than normal blowdown. Well see how it works out I suppose....
 
  • Like
Reactions: 1 person

Hedgerow

Mizzurruh Saw Gangsta
Staff member
Jan 10, 2012
13,621
107,380
113
I am a bit worried compression might be a wee bit much, but like I mentioned, a little added exhaust duration, or a thin gasket will help on that.

I've had real good luck with the two port stihls running a bit shorter than normal blowdown. Well see how it works out I suppose....
Git er dun J!!!

Your 365 shipped UPS today...
It's toting a little extra hardware to sit beside it on the shelf...
:drinkingcoffee:
 
  • Like
Reactions: 4 people

David Young

Well-Known Member
Jun 17, 2013
293
826
93
two questions

first what do you have for a lathe? nice results..

do you think you could save that cylinder with a 064 piston. cut the squish to get ex and transfers under control. the long skirt would gain you a little of the intake back.
then just clean up the ports a little.

David
 
  • Like
Reactions: 1 person