Hi Bob, could you give some indication of what these parts might be? I imagine the motor is a Gama type, with parallel hot and cold cylinders, if so and the cylinders are the same bore, the displacer stroke is made longer, or if the stroke is the same, the bore is increased. Which ever way the ratio between the two is 1.5 :1.

Ian S C

As an aside, for the amusement of grammar/punctuation enthusiasts:

[quote]

Thanks Michael, I'v just come off the Grizzly web site. #16 is the power piston, it is brass 13 mmD x22 mmL this gives you enough to grab it in the lathe chuck. #21 is the displacer cylinder, this should be about 2 mm greater in diameter than the displacer which is #45 listed as aluminium heating piston, and the 15 mm x 40 mm size quoted would be it's finished size. #25 wick holder, I'll leave that to your imagination.I,d bore the power cylinder to about 12.5 mm, it is a nominal size, then make the power piston to fit, it should just slide through, and if you put your finger over the end the suction of it sliding should almost stop it, the clearance will probably be about 0.0125 mm/0.0005".

This is a similar type, although it is smaller with a 3/8" bore power piston, built from the scrap bin, and bits found around the workshop. This motor has ball bearing races for the main bearings on the crankshaft, and the big ends, crankshaft end.  The timing can be adjusted by sliding the vertical column to the left, or right, you can see the brass locking screw on the foot of the column.     Ian S C

Edited By Ian S C on 14/02/2016 11:50:13

Those plans that Dave mentioned can be found on the web. Some of the links that are about are dead.

**LINK**

There are video's of it on his youtube channel.

John

–