Stihl 038 crankcase ????

[briguy26]

I know 038 cases were slightly different depending on if it was a 52mm magnum or 48mmAV/50mm SUPER. Question is what case is the magnum?? I think it's my first picture but any help would be much appreciated.

 

[cscltd]

wouldnt be the one with the largest opening were piston goes at bdc?

 

[Mad Professor]

I know 038 cases were slightly different depending on if it was a 52mm magnum or 48mmAV/50mm SUPER. Question is what case is the magnum?? I think it's my first picture but any help would be much appreciated.View attachment 928762View attachment 928765

Spacing of cylinder bolt holes differ on the 038 mag from others, and 038 may have a ridge on clutch side that needs to ground down also to fit super or mag cylinders. I have no info on ser #s

038 gasket kits come with both base gaskets. It's easy to use those as templates to determine which case you have, also to use as a template for fitting a 038M cylinder on earlier cases.

I've done the conversion, as have others here. Try a search. I didn't have a camera when I did mine. I did evaluate NOS 038S/038M cyl assys and NOS Tecomec when they were still quality Italian made.

I don't have a cyl/case handy to measure center to center of bolt holes, my 038 stuff is at my other place. I do have a cleaned up super case there, and super and mag cylinders there. Might not get to measure them for a while but will post numbers if you need

The hole positions are not a square, front back is different from side/side in both cases. To put a M cylinder on 038/038S you need to slot the cyl holes at an angle to match 038 base gasket, grind cyl where cyl bolt heads seat otherwise they contact and won't thread in straight, and open up fin holes a bit to get the T27 torx to the cyl bolts.

Also, early 038 had magnesium gas tanks/handles, but they can be switched to make a "Frankensaw"

And don't use CHI-COM parts!!!!

Edit: From my notes on first super -----> mag conversion 2008?

The bolt pattern is a little tighter on the 038S than the 038M, more so front to back than side to side. Thus you need to grind (slot) the holes at an angle as the hole differences are greater apart front to back than side to side (e.g. not 45o}. I ground the slots for each hole by ca. 0.040” (front to back) and ca. 0.020” (side to side). There are still plenty of surfaces between the slotted holes and the bore (0.20”) for the base gasket to get a good seal (stock for a 038M was ca. 0.25”).

Edit #2: Pretty much all other parts swap out. > 3 versions of mufflers , 1 2 or 3 port (rare). Muffler port width is narrower on pre- mag mufflers, match early ones to ex port if doing a conversion. Early 038 had smaller Tillotson carb, use later Tillotson on Super/Mag or the Bing from a Mag they are same size run about same and Tillotson parts kit$ are cheaper to buy