6 cube 066

[Deets066]

Did you get any viton measurements or did you wing it?

I cut the groove so that 80 percent of the Viton was covered

 

[Stihlbro]

Pics of top of piston?

 

[thomas1]

Any chance that plating is coming off right at the point your head extends into the cylinder?

 

[Deets066]

Pics of top of piston?

 

[Deets066]

Any chance that plating is coming off right at the point your head extends into the cylinder?

The head drops into the cylinder about .070"

The plating is a good ways farther down than that

 

[Stihlbro]

Does your ring go past the plating at tdc? I see seversal markings around the cylinder.

 

[Termitebuffet]

Ex port and muffler are wet, sounds lean but really isn't far off of a 4 stroke.

It that the pto side next to the exhaust?

 

[Deets066]

Does your ring go past the plating at tdc? I see seversal markings around the cylinder.

The ring is just below the plating at tdc. There is scoring all around the cylinder, worst at the PTO side of the ex

 

[Deets066]

It that the pto side next to the exhaust?

Yes

 

[thomas1]

The head drops into the cylinder about .070"

The plating is a good ways farther down than that

What kind of clearance do you have between the bore and head?

 

[Deets066]

For anyone wondering about fuel it's 32:1 e free 91 octane

 

[Deets066]

What kind of clearance do you have between the bore and head?

I have it wrote down at my shop, I wanna say .005 - .008

 

[Termitebuffet]

Yes

That's the hottest spot buddy , almost all partial/seizes I see start there ...

 

[Deets066]

That's the hottest spot buddy , almost all partial/seizes I see start there ...

I understand that because you get the heat from the clutch and rim.

But in that short of time makes me wonder why

 

[Termitebuffet]

I understand that because you get the heat from the clutch and rim.

But in that short of time makes me wonder why

I just got that other pic to open ...curious that one side looks like something came thru the upper transfer and tried to lodge

 

[CR888]

Bummer Deeter.....so much time, $$ and work and brain goes into this stuff. I'm sure you will win in the end.

 

[Deets066]

So I have a few options on how to fix it.

1. New jug and piston

2. Replate this jug and new piston

3. Bore to 56mm, plate, and new piston.

Thoughts?

 

[thomas1]

Is it possible that between the clearance with bore and the compressed o-ring you're not getting the heat transfer at the top of the cylinder that you do with a 1-piece cylinder?

Is the o-ring totally compressed or is it acting as an insulator?

 

[Deets066]

I just got that other pic to open ...curious that one side looks like something came thru the upper transfer and tried to lodge

That's a possibility, but I couldn't imagine what that would be, I'm very anal about internals being clean when I assemble. And for sawchips to do that is unlikely right?

 

[thomas1]

Maybe heat sink paste between the head and cylinder?