7747 spark control questions.

[Walter Sherwin]

All this talk about "actual" delivered spark advance timing, sparks (sorry
about the pun) me to relay the following and ask a simple question in
return..........

Buried in my file cabinet  (upstairs, far from the wine cellar and
computer),  I have a flyer and an article that described what I thought was
an ingenious instrument at the time.  All of this is probably 7-9 years old.
This instrument would measure the actual spark advance of an engine, based
upon the location of a magnet positioned circumferentially on the harmonic
balancer, and displayed that value as a simple two digit signed read-out on
a round faced red LED.  A driver could either focus on the LED numbers as
they happened, or data log things for post analysis.

By the time I got around to inquiring about it, the inventor/manufacturer
had plunged into seriously bad health.  I had a chance to speak to him
briefly about it over the phone, but when I called back a couple of weeks
later to order one I was informed that he had passed away and that the
product would no longer be produced/sold.

I know it's dirt simple to use a PC based O-Scope to do the same (I have one
here that I use), or even a DAQ system, **BUT**, I think it would be really
cool to have a dedicated spark advance "gage" mounted in the cockpit so as
to be able to read/observe where SA is really at without having to drag out
the laptop each time.  Is this something that a DIY'er could reproduce,
and/or does anyone have a lead as to where this thing may have left-off?
Thought it was a neat idea at the time for CAL'ing and diagnosing, that's
all.  If it was available today, I'd probably order two or three..........


Walt.

If anyone's interested, I can dig-up the flyer, as well as the guy's name.





>
> > > 0 degrees as per the timing decal. If Bias warm is 10 deg. Bias
> > > cold is 20 deg (I think). Winbin table for 50 Kpa @ 600 rpm is 29.88
deg
> > > whereas
> > > Tunercat is 20.1 degrees BTDC. (Using an ARJT as an example).
> > > Winbin adds 10 deg or includes the bias--TC doesn't add it-- so what's
> the
> > > actual "engine" measured timing value at 50Kpa and 600 RPM ?
>
> Winbin is showing the actual amount of timing in the table which the bias
is
> subtracted from.
> TC subtracts the bias from the main table so what you see is what the dist
> will put out assuming what your dist is set to matches the intial timing
set
> in the prom in this case 0. In the above case, 29.88 is what is actually
in
> the main table with out accounting for the bias, 20.1 is what the "actual"
> timing will be set to and includes the bias.
>
> Kevin R
>


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