The cylinder heads on a sleeve valve engine are junk heads. This means that there are piston rings on the head that seal the top of the cylinder instead of a head gasket. The term “junk head” comes from the “junk rings” in steam engines that seal the heads. As the ring in the steam engine was stationary, it could be made from the lowest quality materials hence the term junk.
In a sleeve valve engine the junk head acts as a static or false piston at the top of the sleeve, sealing it as it moves in its elliptical arc.
The heads, are made from 2024 grade aluminum. A 3 foot long 2-3/8 round bar yields 20 1.6 in long blanks. These were faced at both ends in the lathe. There was a lot of material to remove to create the “false piston” on the head so I milled the blanks using the circle wizard in D2nc which made short work of it.
Below the blanks are ready for the next operation of creating the false piston.
