Measuring squish on an (OEM) popup?

[JonCraig]

Probably dumb questions. Working on an 028Super, which of course has popup piston OEM.

Do normal squish measurement methods apply? I typically do the “put four little pieces held on with grease” method.

Am I still shooting for .020-ish?

Does the fact that it’s a popup change my approach in any way?

Thanks!

—JC

 

[pioneerguy600]

You are good to go that way.Tightest area is still where the head joins the cylinder bore. I would run an 028 at .015 up to .020.

 

[JonCraig]

Maybe if I can’t get the cylinder low enough, I should take it for a ride on my belt sander?

What? Something I said? Too soon?

;-)

 

[svk]

Maybe if I can’t get the cylinder low enough, I should take it for a ride on my belt sander?

What? Something I said? Too soon?

;-)

Lol it's winter, so tensions may run high! Lookout lmfao!!!

 

[LegDeLimber]

Never touched one the saws.
So I can't add anything other than watch the popup lump for clearance.

But I do have questions also. if I might trouble you with them.
I'm curious what the piston pin diameter and length are.
Then pin to dome height?

Reason I want to know is that I'm wondering if the piston might be slipped into an Echo pb-620 blower motor!
The 028 super having the popup and listed as 46mm diam makes me curious.

Measuring brand new stock parts.
The Echo pin looks about 1.289" long and .394" diam.

The distance from the top of the pin hole to edge of deck looks pretty close to .750".
The piston is 1.808" anywhere below the ring groves.
It is 1.806" at the (2) ring grooves
The skirt has no taper nor is it ovoid.

The pin bosses are as cast (or glass beaded?) finish & look to be have about .535" gap.