Hello,

Yes the bend is critical and is at 2 degrees to match the centre line of motion, albeit with the motion plate being perpendicular to it. Don made Jersey Lil unnecessarily complex here as he inclined the motion plate at 2 degrees so the bored holes for the valve spindle guides can be bored at 90 degrees and fit the centre line. In all honesty you are better off keeping the frame bend line as it is, keep your motion plate dead plumb and bore the valve spindle guides holes at the 2 degrees – if you look at drawings of the full sized engines this is exactly what they did.

It is a difficult design to build I think: Don never built most of the engines he designed and Jersey is a pain to make and assemble. A couple of mods I have made to the frames for mine are to make both the cylinder stretchers from solid 3/8″ thick steel and scrapped the flanged stretcher with all the 6ba nuts and bolts. You will have the cylinders on and off countless times in the build so mine are held on with x8 4ba 3/4″ long socket screws in blind holes in the stretchers I can buzz off with my electric drill: the cylinders are effectively locked in place in the frame cut outs. The previous builder also made a mod with a small cut out in the frames where the cylinders protrude to allow the valve stuffing box and spindle through so the valve chest can be bolted to the back of the cylinder block, otherwise as things stand it is impossible to assemble the second valve chest inside the frames without taking them apart!!

I hope that helps!