Shelly's 1/3 Woodpecker hit and miss engine

[gbritnell]

Gentlemen,
If anyone has built this engine I would sure like to get a dimension from you. What I need is the dimension from the centerline of the crankshaft to the head face on the base casting. The drawing doesn't have it and if I scale it it takes too much stock off of the casting and intrudes on the spark plug boss.
Thanks in advance,
gbritnell

 

[Catminer]

George;

I don't know if my amateurish answer will help much but I am currently working on a Woodpecker myself.
I ended up with 6.1585" crank center to deck height. I arrived at this by the non scientific approach of trying to center the plug in the boss and maintaining the distance of the piston head to spark plug port.
I also used a 1/4" long reach spark plug rather than the 10mm in the drawing, it is closer to scale proportions. I have a few pictures of the real thing and am trying to replicate the full size as much as I can.

Peter

 

[gbritnell]

Hi Peter,
Your dimension sounds about right. I scaled the drawing for the given dimensions and they were pretty close so I scaled the distance from the centerline of crank to the head deck and got 5.938 (give or take). The problem was if I cut it to that I will be in the plug boss too far.
The drawings for this engine were done on a computer with a drafting program but supposedly the computer crashed and everything was lost.
When the drawings were being made it's hard to believe that the needed dimension was overlooked.
I can redraw everything I have and come up with a dimension but I didn't want to spend that much time on it.
Thanks for you help,
gbritnell