Stuart No 9 question

[Walsheng]

I am in the process of building a Stuart No.9 engine with a governor and pump. The castings have been "normalizing" since 1979 so I think they are about ready.
I have been able to noodle out just about everything on the print (I think) except the depth of the piston ring groove.
Does anyone have the Tubal Cain book on building the No. 9?
Or does anyone happen to know how much clearance is correct?

Thanks,

John

 

[deverett]

John

I have just had a look through the Tubal Cain book and there is no mention of the ring groove depth. All he says is that the ring gaps should be square and 2 or 3 thou when the ring is in the bore. Not really helpful, I'm afraid.

Dave
The Emerald Isle

 

[Walsheng]

Dave: Thanks for taking the time to look it up. I ordered the Tubal Cain book but it is out of stock at Coles Power Models but I guess having it would not help on that point.

Anyone have an idea what would be correct for a 1-1/2" piston ring?

John

 

[kf2qd]

What the material for the rings and for the piston? At least a couple thou . You want enough to account for any wear on the piston, but then the rings are going to wear also.

 

[Walsheng]

What the material for the rings and for the piston? At least a couple thou . You want enough to account for any wear on the piston, but then the rings are going to wear also.

According to the parts list the piston and rings are cast iron. The print calls out for 1-1/2" for the piston OD and 1-1/2" for the cylinder bore (cylinder is cast iron as well.) I would think the piston would want a little clearance so the rings can do their job with .xxx amount of clearance between the piston and rings so the rings can float a bit? It's the .xxx I am not clear on.

John