0.043" squish

[rmihalek]

I was trying to measure the squish band in my 266 cylinder using the solder method. So, I stuck a piece of solder into the plug hole so that it goes all the way to the edge of the cylinder then I turned the engine over. I felt the piston squeeze the solder. Then, I pulled the solder out and noticed that it tapers down to about 43 thousands at the end. So, I guess that means the squish band is 0.043". I'm wondering if this sounds about correct to those who have experience measuring these things? I realize that not all saws are the same, but perhaps they are all around this value?

 

[bwalker]

You have to use two pieces of solder positioned. Position them so each is directly above the wrist pin boss.

 

[ehp]

Bob did you put the solder in the jug so it was the same as the crank in direction and in the centre of the bore on the outside so you get a accurate measurement because of the piston rocking .If you measure from the intake or ext. side of the jug you will have piston rock. Most huskys that are stock with base gasket are around .050, stihl's are around .040

 

[rmihalek]

Thanks for the replies Ben and Ed. I didn't factor in crank direction and piston rocking, so I'll have to re-do the measurement. I'll try Ben's suggestion of using two pieces of solder and position them over the wrist pin boss.

 

[Crofter]

Bob, depending on the size of solder you use, you might want to split the ends in two to reduce the effort of squishing the solder.

 

[YUKON 659]

Bob, depending on the size of solder you use, you might want to split the ends in two to reduce the effort of squishing the solder.

I'll second that...I think the solder I tried to use was about an 1/8" and it was almost impossible to turn the saw over. What I did was pre flatten the solder to about 1/16". I think Frank's idea of splitting it would be better, or better yet find some thinner solder to start with.

Jeff

 

[Crofter]

The no lead solder for plumbing is extremely hard too. Cant tell you off hand which is softest though.

 

[timberwolf]

I found the flux cored electrical solder good, its soft and is of much smaller diameter less than 1/16 of an inch

 

[rmihalek]

Yeah, I was using the flux core electrical solder with O.D. of about 1/16th. I could crush the solder just spinning the flywheel with my thumb- it's pretty soft.

I'm wondering what squish band clearance I should shoot for when doing the modifications? Is 0.020" too little? I don't know how much effect the rpm's have on the squish, but I don't want to find out that the piston hits to top of the cylinder when the saw is at 12,000 rpm.

 

[ehp]

Bob .022 to .025 is very safe and works fine

 

[bwalker]

Yukon, Witht he changes you have made that saw should be a stump puller. You will lose some peak hp though as you have in effect lowered all your ports...try a 9 pin maybe,lol.