Randall Young wrote:
> Electronic ignitions fall into two broad categories : those that work by
> inductive kickback in the coil (as points do); and those that generate a
> relatively high voltage then use the coil as a step-up transformer. The
> first category (sometimes called point amplifiers) are, in effect, just
> electronic switches that replace the function of the points. The
> Pertronix, Crane XR700, and most OEM auto electronic ignitions fall into
> this category.
Agreed very much, but I wanted to be sure this point was
brought up to show that the Crane and Pertronix were similar
in this category.
While I prefer the Crane, I didn't want someone watching
the thread to decide between Crane and Pertronix to see
the comment that "the Pertronix isn't a [spark amplifier]" and
beleive that the Crane was and use that to make a decision.
As mentioned SOME Cranes are, but the ones that are
are not price-competitive with the Pertronix. (I have
one of each type of Crane, the 700 and the 3000)
> This is the distinction Joe was referring to, and it's real. IMO the
> big advantage of the first type is it's relative simplicity, which
> should translate to lower cost and better reliability.
Worth mentioning, even a "plain jane" type electronic
ignition can increase performance, because the on-to-off
transition is much more abrupt than that of points. Since the
strength of the spark is proportional to the speed of
the collapse of the magnetic field....
As well, many cars use ballast resistors to strike
a balance between spark energy and point life. No such
item required with an EI.
I *THINK* my car runs smoother with EI, but I can't say
I am sure enough to scientifically declare it. I'm human
and I'm succeptible to the same emotions that make you
think the car runs smoother after an oil change. :>
However, I am extremely sure that all my cars start
a lot better after the EI conversion. A good fat
spark can make the difference there between a one crank
start and a four crank start.
So, I wouldn't be too firm with the "normal solid state
EI systems just replace the points", because well... they
do, but they replace them with what you might
consider "idealized points", and you really are better off
in more ways that just less time in the garage.
The CD and MSD systems go a step beyond.
> Randall - almost a EE, but got distracted by computers <g>
Similar situation here, I have a CE degree which came from
an EE school and was about 90% the same courses.
--
Trevor Boicey, P. Eng.
Ottawa, Canada, tboicey@brit.ca
ICQ #17432933 http://www.brit.ca/~tboicey/
"A car is fine, but a truck is a force." - Peggy Hill
///
/// triumphs@autox.team.net mailing list
///
|