This is how I measured my 200Ts squish clearance

[MattG]

I thought I'd share the saw mechanics I did the other day. I decided to get the squish set aswell as I could on my 200T. The measuring process works as follows.

 

First remove the cylinder, and glue using some grease 4 pieces of 1mm thick leccy solder.

 

Lob the cylinder back on. Note that I previously marked on the cyl and the fly wheel reference point so that I could get to TDC quickly.

 

Move the f/wheel and thus the piston a few degrees past TDC, then back a few several times to get the solder squashed.

 

Remove the cylinder, and carefully measure (micrometer or vernier calipers) the solder where it was squashed. The figures should give you an indication of your clearance.

 

Hope this helps someone.

 

Matt

[Deafhead]

You could also use Plastigauge. It is useful stuff for measuring all sorts of clearances.

[Stubby]

And are you going to make any adjustments ?

[bmp01]

Is the 200T subject to the same sort of tolerances as the rest of the range or do Stihl make a special effort on these?

 

How about shooting for 0.45mm (18 thou) as a starting point for your mods

 

bmp01

[MattG]

When I first roughly measured the clearance it was about ~1mm. Discovering that the base gasket is 0.5mm thick I discarded that, and after polishing the roof of the combustion chamber, I discovered casting artefacts (I'll post an image when I'm next home), which reduce the squish around the periphery. Accounting for these, gave me, between 0.34mm (under the artefacts) and 0.55mm in the main area.

 

So I'm looking shim out a tad by about 0.08mm. I'll keep you posted.

[Stubby]

Whats a casting artifact ? Could you take it on the antiques road show ?

[MattG]

Whats a casting artifact ? Could you take it on the antiques road show ?

Hey Stubby,

 

Firstly - ha ha!

 

Secondly - I'm not at home, so tell me if you can see the image here:

 

Measuring squish on my MS200T | Outdoor Power Equipment Forum

 

and if so, you'll see what I mean. They are from the casting mould, and are very annoying in squish setting.

[Stubby]

Hey Stubby,

 

Firstly - ha ha!

 

Secondly - I'm not at home, so tell me if you can see the image here:

 

Measuring squish on my MS200T | Outdoor Power Equipment Forum

 

and if so, you'll see what I mean. They are from the casting mould, and are very annoying in squish setting.

 

If I click the link it opens up the " Power equipment " page with your post and some pics .

[MattG]

So the "artefacts"

 

are those imprints around the periphery of the combustion chamber outer dome (first pic). And they protrude into the CC, by 0.15-0.2. Very annoying. As you have to shim out to give them clearance and that makes the regular squish's clearance bigger than needs be.

 

The cyl is the OEM Mahle/Stihl. So its a shame they don't lathe these flaws, call them what you like, off after the cast.

 

Have you ever seen them before?

Matt

[Stubby]

I thought ( wrongly perhaps ) that the squish band was just the area around the periphery ?