3. Ran out of day before I finished yesterday. Happens more often, these
days. So, after the silicon chip revolution subsided a bit, we found
ourselves smack dab in the 70's. Detroit didn't know whether to keep on
with building MUSCLE CARS, or pay attention to the gasoline shortage?/Oil
embargo that 1973 brought, and make more anemic vehicles like the Vega or
Monza, or K cars etc. But, VW rabbit sales made them sit up and say
"HOWDY".
So, EMISSIONS reared it's ugly head, and they got caught up in making
their products compliant.
SMACK DAB IN THE MIDST of this came development of High Energy
Ignitions. The big three all had their versions, and GM had their share of
learning experiences. After a bunch of transistor ignitions were developed,
and were fraught with failures, GM bit the big bullet, and spent the money
to develop something that filled their needs. Had to last at 50,000 miles
without service. Ignition points needed service every 10,000 miles. So GM
engineers used 100,000 miles as their target. That was TEN TIMES as long
as points. Quite a lofty goal. But, they prevailed with their HEI. The
moving parts are limited to a gear driven distributor shaft with a rotor to
distribute spark around the circumference of the cap. The mechanical
advance mechanism consists of flyweights and springs, like points
ignitions, and the vacuum advance/retard mechanism is also similar to the
ones used with points. Triggering of the primary circuit is by hall effect.
Primary voltage is no longer limited by how much current the points will
stand before they burn up. The higher the primary voltage, the higher the
secondary voltage can be.
I used an Allen Smartscope for tune-up, and HEI will easily drive the
trace off the screen that has a 60 kv range. Yes, it will easily jump a
1/2" gap, or bite you through a pair of Snap-On plug wire pliers. You won't
hold on to it long, I gur-an-tee you.
In mid-year 1975 GMC started fitting the HEI to their Olds 455
engines, and when the 403 engine was introduced in mid-year 1977 it was
fitted on those as well.
I have a 1978 GMC ROYALE with a 403, and it has over 130,000 miles. On the
original HEI distributor. Cap and wires have been replaced in nearly 40
years of service, and I neglected the spark plug gaps, let them open up too
far, and smoked a module. My fault. So don't "bad mouth" a GM HEI Ignition
in my presence. Nothing else even comes close to it. Your opinion WILL vary.
Jim Hupy
Salem, Oregon
> Back from my first round of errands. So, as electrical loads increased in
> automobiles, shortcomings in electricity producing devices did not keep
> pace with demand. Permanent magnets were only so strong, so their
> electrical fields were limited. No field strength means no high amperage
> output. Commutators would wear carbon brushes out quickly, and required
> frequent maintenance to remain in top form.
> Soooooo, along came inside out generators, they rotated the magnetic
> fields (called rotors), and took current off a stationary winding called a
> stator. Several incarnations were developed, but a wye (Y) configuration
> pretty much became the standard. 1 end of each winding (there were 3) were
> joined together, and each other ends were attached to a separate diode.
> (Diode trio) 120 ° out of phase with each other. Regulation is a simple
> matter of turning the field off and on, thereby limiting field strength and
> thusly ALTERNATOR OUTPUT. The GM design pretty much rules the roost.
> During this time the solid state devices (transistors, thermistor,
> solid state diodes, etc.) took giant leaps forward. Integrated circuits,
> etc. became commonplace. Uses varied from microwave ovens to spacecraft.
> Cellular telephones, home computers, etc.
> I will follow up more later. File length limits.
> Jim Hupy
> Salem, Oregon
>
> On Fri, Jan 31, 2020, 12:16 PM Johnny Bridges via Gmclist <
>
>> Actually, my fave is the 70s Mpoar setup. The only failures I have seen
>> with them is a) the dual ballast resistor and B) poor grounding of the
>> module. The resistor is an easy fix, Ohmite is Your Friend. The second
>> time rust got under the mounting bolts in my 340 car, I took the Dremel and
>> ground down to bare metal on the module and the inner fender and used my
>> old American Beauty iron to solder a braid between them. Never had a
>> problem
>> with it after that, and while we built it back to go, the C/R wasn't
>> really stupid - 10.5:1 I put copper plug wires which wiped out every AM
>> radio for
>> half a mile. When I was driving it sensibly it used a graphite coil wire
>> which shut the noise up. Playing Stoplight Choose-Off, it got the solid one
>> back, and devil take the radio.
>>
>> --johnny
>> --
>> Foolish Carriage, 76 26' Eleganza(?) with beaucoup mods and add - ons.
>> Braselton, Ga.
>> I forgive them all, save those who hurt the dogs. They must answer to me
>> in hell
>>
>>
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