Why Upgrade Your Older Jeep Ignition?

Because it won't start, it won't idle, gets horrible fuel milage, and you can't pass a Yugo on the highway...


Let's face it, AMC was in SERIOUS trouble the last 15 or so years of it's existence...

Research & Development takes lots of money and time, then you have to do the legal work, patents and such.
All time and money that AMC didn't have.

So what AMC did was go 'Dumpster Diving'...
Transmissions were bought from Chrysler (Torque Flight) and General Motors (Turbo Hydromatic), axles from Dana-Spicer mixed with AMC's own axles, and transfer cases from Borg-Warner and Dana-Spicer.
Carburetors and Ignitions were purchased from Prestolite, Ford (Motorcraft) and Chrysler (Carter).
Charging systems were from Prestolite, Motorola, Motorcraft, Delco and I don't know how many others.

What this left us with is a hodgepodge of often mismatched parts that were outdated when installed.
(Do you REALLY think that GM or Ford gave up the latest versions with the best R&D?...)


The gap in R&D, Combined with 30 Years of hind sight allows us to use factory stock & aftermarket parts to make our Jeeps as road worthy and dependable as they should have been from the factory.


WHAT AMC/JEEP WAS UP TO.
Jeep used the small 'well' type distributor cap, short rotor, low energy ignition spark plug wires and low output ignition coil to save money.
Those money saving items are the problem.
The distributor cap design is left over from the 1920's. (WWI technology)
The plug wires haven't changed in any distinct way since the 40's. (WW II technology)
The ignition coil is still based on the oil filled units that appeared in the 1920's. (WW I)

HIGH PERFORMANCE UPGRADES EXPLANATIONS:
We Will Start With The Distributor Cap & Rotor...
Jeep, '1978 to '90 used a Ford Motorcraft Distributor and DuraSpark ignition module, but they left a small 'Well' type distributor cap on the distributor, while Ford used a two piece distributor cap adaptor attached to the distributor, and a separate 'Cap' with the actual terminals in it.

Here is a comparison of the two types of caps & rotors.

As you can see, the Distributor Cap Base lifts up the distributor cap, and puts more physical distance between the high spark energies and the grounded internals of the distributor.
This helps stop spark energies going to ground and causing misfires.

The Taller Rotor serves the same purpose, and keeps spark energy from being lost to the distributor shaft like the GM HEI has a real problem with.

The Wider Distributor Cap physically moves the high voltage terminals apart to help stop cross fires inside the cap.
The Wider Distributor Cap also has the much more desirable high energy 'tower' type terminals. (they look like spark plug tops, instead of 'Wells' that hold moisture and 'crud'...)
The spark plug wires that are designed to work with this type of cap can manage the much higher voltages of the high energy ignition coils, and have much better boot designs at both the distributor cap and at the spark plugs.

The later model two piece caps are often vented, and this reduces the Ozone buildup in the cap. (Ozone is O3, also known as Ionized air, and is created by the high voltage discharges inside the cap)
Ozone will promote cross fire, multiple firings (where more than one plug is fired), and ground fires (where the high voltage discharge goes to ground instead of going to the spark plug terminal).
By Venting this gas, the distributor cap will get the spark energy where it's supposed to go more reliably.

Now Moving On To The Ignition Coil...
AMC/Jeep used a routine 'Canister' type ignition coil until the company's demise in 1990.
The first 'Canister' ignition coils were used on aircraft during WW I...
Canister coils are oil filled for cooling, and have to be mounted upright (with the high voltage terminal vertical), and can overheat and fail if mounted in any other position.
Because of their design, oil filled 'Canister' coils are very low output by todays standards.

Here Is A Comparison Of The Canister Coil & The E-Core Coil.



GM started using an 'E-Core' coil in 1972, and put them on everything in 1974. (the famous 'HEI' Distributors)
Ford introduced it's first 'E-Core' ignition coil in 1985 and put them on everything in 1992.
The "E-Core" Ignition Coil is a high output epoxy filled unit that can be mounted in any orientation, puts out about 2-1/2 times the usable spark energy of the typical 'Canister' type coil, and about 1-1/2 times the usable spark energy of the GM HEI in cap coil, with out affecting the ignition trigger, and the current is delivered in a controllable manner.

Let's Discuss Spark Plug Wires... The first generation of sparkplug wires had solid copper or stranded copper as a conductor, and layers of cotton fabric alternation with rubber for an insulator.
The first generation of plug wires were secured by simply twisting the conductor around a threaded post, and securing them with a common nut or knurled thumb screws.
This was considered 'State Of The Art' when it was used, but in hindsight, we now marvel that the engines even ran at all!

With the advent of radio being installed in vehicles (during WW II), something had to be done about the Radio Frequency Noise (RF for short), and so was born the Graphite core wire.
These wires didn't use a solid copper conductor. The conductor was a Graphite and Fiber, insulated by the usual fabric and rubber with little or no attention paid to the connections.

Somewhere along the line, manufacturers started installing folded metal ends as connectors, and putting primitive insulating boots over the connections to help stop some of the moisture and RF problems.

Later came strands of polyester and plastic insulation, mostly because it was cheaper and easier to manufacture.
Plug wires pretty much stayed this way until the Emissions Standards and Milage Standards set forth by the government forced manufacturers to Update and Upgrade the 'Status Quo'.

When Professional Racing became a multi-million dollar business, the racers could hire the best engineers, and some real practical advances were made.
Capacitive Discharge Ignitions, E-Core coils, and Spiral Wound Silicone insulated plug wires became the standard if you wanted to have any chance of winning.
Much of this engineering has found it's way into modern production vehicles simply because the government has mandated fuel milage and emissions standards, and this technology is the least expensive route for the large auto makers to achieve the mandates.

This is all good news for those of us that have the ambition to adapt the new technology and superior parts to our older vehicles.

Now, Some Time Devoted To Distributors...
Out of all the fully mechanical distributors out there, the latest design is simply the best for the application where AMC/Jeeps are concerned.

Fully Mechanical Distributor means it has mechanical vacuum advance and mechanical centrifugal advance, instead of a 'Timing Computer' just connected to a trigger in the distributor.

Ford (Motorcraft) actually did have a better idea in this case.
Ford was more than 4 years behind GM and Chrysler, and that extra Research and Development time paid off in a big way with the Motorcraft/DuraSpark ignition system.
Ford was able to design out many of the defects that plague GM and Chrysler, and since the system was offered as original equipment in AMC Jeeps, we can benefit from any of a number of upgrades and advances Ford used through the years.

The Ford style magnetic trigger in the distributor has become the standard in most kinds of racing and aftermarket distributors.
Fords style of two piece distributor cap is most desirable if you use a high energy ignition coil, or just want to stop the cross firing and ground firing in the small well type caps.
Fords Motorcraft distributor is VERY reliable, very tunable, has been installed in every I-6 and V-8 AMC Jeep from 1978 to 1990.
This makes it most desirable, since it was factory installed, we either already have one, or can install one in under an hour.
Every discount auto parts store carries entire distributors or just the parts to repair or rebuild yours at very reasonable prices.


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