David,
Excellent summation. I have a few additions. This was not only true on
MGs, but also TR7 and Spitfires, and Jags. I have a dim memory that the new
"brain" boxes were made in the US... Judson maybe? (the people who made CDI
systems).
There were other makers of replacement ignitions for the older EI
dizzys.
Lumenition (still extant) and Piranha (marketed by Nisonger in the US) both
UK manufacturers. Piranha was also optical. Lumenition is magnetic (Hall
effect?) I mention this because you may occasionally come across this
stuff. We used to sell a lot of it before Crane/Allison. Piranha had 2 kits
depending on if you had the 45DE or DM breaker plate as there is a
different hole that they used. The old EI 45DE dizzys are also refered to
as Lucas Opus system. Crane refers to them that way in their catalogs.
Peter C
At 08:15 PM 2/17/2000 , David Riker wrote:
>OK, summary time, (those of you running points and condensers, may hit
>delete if so desired.)
>The 1500 through '78 came with a 45DE distributor. This has a plastic ring
>on the distributor shaft under the rotor with magnets imbedded in it and an
>ignition amplifier module imbedded in plastic and mounted on the side of the
>distributor intregal to the vacuum advance/retard.
>
>In 1979 1500's and 79-80 MGB's, and on many cars repaired by BL service
>centers due to failure of the 45DE modules, have a 45DM distributor. They
>have a metal round thing with four spikes on them slipped on the distributor
>shaft under the rotor. These spikes are the magnets. These use a remote
>ignition amplifier module model AB14 that contains the GM module I've
>mentioned in previous posts.
>
>Allison electronic Ignition kits (early) and Crane (later) conversion kits
>(one in the same, Crane bought out Allison Ignitions) use an optical sensor
>activated by a plastic disc with 4 cutouts that slips on the distributor
>shaft under the rotor and spins between the two optical sensors. The
>plastic disc is what we are calling a chopper. This kit also utilizes a
>remote Amplifier.
>
>The 45DE module fails due to excess heat in the engine compartment. They
>are frequently upfitted to Allison/Crane units, which are also highly
>susceptible to excess heat and moisture. The benefit of this upfit is that
>Crane is still servicing the unit, and has (had?) a lifetime warrantee. I
>have seen some people mount the Crane Amplifier inside the passenger
>compartment of the car to get it as far away from potential heat and
>moisture sources as possible.
>
>An ignition module that is going bad may misfire at high Rpm's, or the car
>will die unexpectedly, often with a loud backfire, and tach drops to zero
>and stays there dispite turning the engine over, and then suddenly bounces
>backup and runs fine again for a while. My wife got a new Honda after our
>MGB stranded her for the eighth time while I figured this one out.
>
>As is everything on the list this should be considered for entertainment
>purposes only, yada, yada, yada. Persons more knowledgeable about this
>subject than me may feel free to put me politely in my rightful place.
>David Riker
>74 Midget
>78 Midget
>63 Falcon
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