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Re: Crane vs MSD

To: Barry Schwartz <bschwart@pacbell.net>
Subject: Re: Crane vs MSD
From: kehrlich@dyax.com (Keith S. Ehrlich)
Date: Fri, 16 Jul 1999 16:35:28 -0400
Cc: triumphs@autox.team.net
Organization: Dyax Corp
References: <3.0.6.32.19990716065648.0090a100@pacbell.net>
Barry Schwartz wrote:
> 
> If they (speed shop)really said these things as stated, then they indicate
> that they really don't know of what they speak, or were misinformed.
> Most of the original is snipped, but the pertinent information is noted and
> corrected-
> ******************************************
> >They said that the MSD operated
> >off a regular set of points installed with no gap.
> ******************************************
> There has to be SOME gap or you won't have anything to trigger the system.
> If your using the points, you have a mechanical switch.  This is what
> "tells" the electronic box when to turn "on" and "off " the supply voltage
> to the coil.  If it were installed with the points set with NO gap, then
> the "switch" would be constantly on.  There must be a gap setting for the
> points if used.  However, it may be a reduced gap for some reason, although
> I don't see the benefit if it's truly a digital system the gap would seem a
> mute point (see more below) and actually, I would think there would be a
> greater chance of point bounce, and a faulty trigger, with a reduced gap
> (IMHO)
> ******************************************
> > They also said the Crane units
> >are solid state and can be damaged by leaving the ignition on for
> >extended periods of time while the MSD's are digital and do not suffer
> >this damage potential.
> ******************************************
> Not quite correct again.  BOTH units are solid state.  The term (solid
> state) referring to the internal construction of the units I.E they use
> some sort of semiconductor in it's construction, be it either transistors
> or I.C.'s.  Analog or digital refers to the way they operate, NOT the
> construction of the units, and in no way reflects the reliability rating.
> The type of operation (analog or digital) may however give one unit an
> advantage in how well it processes adverse inputs, and it's ability to
> deliver a more controlled triggering signal, but it won't make one unit
> last longer or survive incorrect assembly or operating conditions.  That
> would have more to do with the internal design and construction of the unit
> in question and how well the designers safeguarded these perceived
> conditions. Now, having said that the MSD may well be designed better in
> this respect then the Crane unit.  I can't say since I have never looked at
> either design internally.  I can however, say that I have used a Crane unit
> in one form or another (when they were Allison) for over eighteen years
> with nary a problem.  The one in the GT6+ has been working faithfully (with
> it's Lucas Gold Sport Coil) for over eight years now-
> 
> Barry Schwartz (San Diego) bschwart@pacbell.net
> 
> 72 FI, V6 Spitfire (daily driver)
> 70 GT6+ (when I don't drive the Spit)
> 70 Spitfire (long term project)
Barry you are right. I realized the foolishness of what I wrote after
hours. I called MSD direct before your response and they confirmed what
you said-that the gap in the points is set to factory specs. Their tech
person said that points wear, being a little off from factory spec and
distributor wobble were not big  issues because the black box takes care
of dwell. Which is not to say that you don't need to change points from
time to time, they would just last a little longer before replacement or
reset. He offered that magnetic pickups like the Ignitor would work
well. He also said the other purpose of their box was to deliver a spark
stream, not necessarily a more powerful spark. He politely declined to
offer a comparison to Crane.

Now off to the corner for me.

Keith

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