Timing, w/o buzzbox

Let'sgoflying!

Let'sgoflying!

Touchdown! Greaser!
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Dave Taylor
How did they external-time mags in the old days? Looks like someone walked off with my timing indicator.
Have VOM, have icepick style test light.
 
Yeah, I dunno that I'd want to do that. Part of having the buzzbox is that the mags are grounded through it when attached to the p-leads so they won't fire.

$70 for a new one looks pretty cheap to me.
 
Old days? How old?

At one time I had a buzz box made with a door bell buzzer and a neon bulb.
 
Capt. Geoffrey Thorpe said:
Old days? How old?

At one time I had a buzz box made with a door bell buzzer and a neon bulb.
Click to expand...

THAT'S funny!

Couldn't you do it with a typical meter? I'm obviously E-stupid but it's just telling you an on or off something isn't it?
 
flyingriki said:
THAT'S funny!

Couldn't you do it with a typical meter? I'm obviously E-stupid but it's just telling you an on or off something isn't it?
Click to expand...

An ohmmeter has to be really sensitive to tell when the points are open or closed. The points are connected across the coil's primary winding, which has very little resistance. Might see less than half an ohm. The buzzbox timer takes DC from a couple of batteries, runs it though a buzzer (newer units do it electronically) which chops it into pulsed DC. The coil reacts to that the same way it would to AC: it has inductance that resists changing flow, and it shows up as resistance to the buzzbox. When the points are closed, the buzzbox sees no resistance; basically, the points short out the indicator lights. The points open, inductive reactance creates resistance, the lights come on.
 
Thanks, I guess buzzboxes have been around since the 30's then - I figured they were a modern contrivance.
 
Capt. Geoffrey Thorpe said:
At one time I had a buzz box made with a door bell buzzer and a neon bulb.
Click to expand...

I've got one of those that I made too.

Look online and you'll find schematics on how to make a magneto timing box. I seem to recall some of the tractor forums having information about it.
 
I use the audio output (speaker output) of a small radio as a signal source. I add a set of leads (actually I use 4 wires) from the radio's speaker output, to the magneto terminal and magneto ground terminal arranged so that the speaker signal is in parallel to the magneto primary.
 
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