As I was browsing the parts manual last night, I had a epiphany,
realizing in my haste to get the motor back together, that I forgot to set
the valve lash.
I soon found out that the heads needed to come off to do so, and after the
valve stems were shortened to get them back to specs, I decided to
check the ignition timing, as long as the heads were off.
I know of no other way to tell where TDC on the pistons are, as the spark
plug hole is angled, and over the valves, not the piston.
In looking it over, I found another set of punch marks on the opposite side
of the coil / mag. plate, and I’m not sure either set is the correct ignition timing.
The points are set at .020 per manual, and there’s no other timing information given.
I seem to remember some small engine manufactures gave timing information
in degrees of crank rotation before top dead center (BTDC), piston travel BTDC,
or both.
I hooked up my ignition “buzz box” on the mag plate to know when the points open,
and set up a dial indicator.
The closest I can get the points to “open” is .023 BTDC, by moving the mag plate on
it’s slotted hold down.
Neither set of punch marks are lined up at this point.
To further confound things, I just discovered that this twin opposed motor (with one coil) is one of those
“wasted spark” motors. When both cylinders are at TDC, both cylinders will spark, but only one
cylinder is charged with fuel, and the other cylinder has it’s exhaust valve open.
180 degree rotation, and the other cylinder is charged with fuel and ready to fire at TDC.
It would be nice if someone had some timing specs or procedures, but lacking that,
I’d be grateful for any thoughts on “winging it”.
After tomorrow, it will be a few days before I can reply.
Thanks!
https://youtu.be/dJ8NkjiYRDY
Prepare to be boarded!
