[Fot] Mallory dist now Vertex magneto

[John Herrera]

Amici,
>
>  The shop I work at has an XK-120 with a
>Vertex Scintilla magneto ignition in for repair.
>The drill for starting it is: Pull fast idle cable,
>Pull starting carb solenoid switch on, Turn on
>key switch, Push starter button, Then turn on
>magneto toggle. I'm not familiar with this magneto,
>is there any advance built into it? Just wondering.
>
>Bill
>Triumph Rescue

I don't know if this will help, but:

If it's like an aircraft magneto, there is no advance in it. You static-time 
an aircraft magneto to a given degree before TDC and it fires there every 
time. The spark event doesn't change.

There is a spring-mechanical coupling device (called an impulse coupling) 
between the mag and the drive gear that retards the spark until TDC during 
starting. It disengages once the engine starts and the mag fires at the 
setting BTDC. Don't know if car mags have impulse couplings.

Aircraft engines run in a very small RPM band, so car mags might be 
different.

John