[SEL] FMZ Gear - serious reply

[Rob Skinner]

On Dec 3, 2008, at 3:00 PM, Al Harris wrote:
> Please don't egg them on. The gist of this thread has been totally
> lost/stolen/misappropriated/bent and forgotten. It was about the  
> gear I
> need to complete my FMZ.


Hi, Al.
Hopefully the extended exchange will help you in your quest for the  
proper gear for your engine.

The following will not solve your dilemma, but will throw some light  
on a subject where some have played fast and loose with the words  
"never," "always," and "must."

Check out a picture (link below) of Greg Procopchuk's Jacobson  
engine.  It's a traditional four cycle engine, with 720 degrees of  
crankshaft rotation between firing.  You can't see much detail in the  
photo, and on that day I was shooting film, so a better picture is not  
readily available.

The CAM GEAR is the big one nearest Greg.  It's also the pump jack  
gear.  Although you can't see the gear on the crankshaft, you can tell  
it's considerably smaller.  I forget what the ratio is, but I seem to  
think it's four-to-one.

As you've probably already figured out, the cam as a few extra lobes.

Link:
http://engines.rustyiron.com/tulare04
Click on the fourteenth menu item from the top.

Good luck finding your gear.
Rob