Genuine Junk Yard Genius.com Ignition Upgrade For:
AMC/Jeep 258 CID (4.2L) I-6 Engine, 1978-83
There are three upgrades listed below, so make sure you read the entire upgrade sheet before making up your mind.
No options and has to be done all at once.
2. MILD PERFORMANCE UPGRADE.
3. EXTREME PERFORMANCE UPGRADE.
This upgrade is primarily for serious performance enthusiasts.
A fair amount of modification required.
This is an upgrade that should only be done after the first and second upgrades have been done.
1. BASIC UPGRADE;
USE THIS UPGRADE ONLY IF YOU INTEND TO USE YOUR STOCK COIL AND WIRING HARNESS WITH NO
MODIFICATIONS.
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WHAT GETS REPLACED.
Stock Parts To Replace: (stock jeep components)
Distributor Cap, Rotor, Plug Wires.
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What To Use For Replacement:
FROM: A 1981 Ford F-150 Pick Up Truck With A 300 CID I-6 Engine.
Distributor Cap Adaptor,
Distributor Cap,
Rotor,
FROM: A '94 Jeep With 4.0 Liter Engine.
Use A Spark Plug Wire Set from a 94 Jeep with 4.0 Liter engine.
Most people report this is a better fit than using the Plug Wires from a Ford 300 CID I-6 engine.,
Make sure you don't forget the basics, and get a good quality distributor cap & rotor with brass terminals or you are just wasting time and money with this upgrade.
THIS BASIC UPGRADE REQUIRES NO MODIFICATION OR FABRICATION OF ANY 'HARD' PARTS. IT IS
ALL DIRECT REPLACEMENT OF EXISTING PARTS.
2A. MILD PERFORMANCE UPGRADE.
These up grades are designed to enhance the already formidable Motorcraft ignition system.
This upgrade will surpass the GM HEI system by about 1-1/2 times...
(YES! That's correct, the Motorcraft E-core Coil stomps the snot out of the GM HEI!)
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WHAT GETS REPLACED.
Stock Parts To Replace: (stock jeep components)
Distributor Cap, Rotor, Plug Wires, Ignition Coil, Distributor Advance Springs.
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What To Use For Replacement:
FROM: For A 1981 Ford F-150 Pick Up Truck With A 300 CID I-6 Engine.
Distributor Cap Base,
Distributor Cap,
Rotor,
FROM: A '89 Ford Escort With I-4 Engine.
This will provide you with the correct
E-Core Ignition Coil.
Any Ford Vehicle With ECC Will Use The Same Ignition Coil & All Will Interchange.
FROM: Aftermarket: Napa Auto Parts, P/N ICC 1.
E-Core Coil Connector Will Be Needed To Properly Connect To The E-Core Ignition Coil.
FROM: Aftermarket, Salvage Yard or Fabricate.
E-Core Coil Bracket. Your new coil will need a bracket.
Many people have picked them up in salvage yards for a couple of bucks, or made one from a 4"
piece of angle iron.
Most 'Chrome Shops' and after market hot rod suppliers have the brackets for cheap.
FROM: A '94 Jeep With 4.0 Liter I-6 Engine.
A Spark Plug Wire Set. This should give you the correct coil wire.
Most people report this is a better fit than using the Plug Wires from a Ford 300 CID I-6
engine which can also be used.
Make sure you don't forget the basics, and get a good quality distributor cap & rotor with
brass terminals or you are just wasting time and money with this upgrade.
2B. MILD PERFORMANCE UPGRADE.
This part of the upgrade doesn't have to be done at the same time as the 2A Upgrade.
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AMC Jeep 258 CID I-6 Engines From '78 to '83 Used A Full Mechanical Centrifical Advance
Distributor To Add Ignition Timing As Engine RPM Increased.
Tuning The Distributor With Centrifugal Advance Springs Will Work With This Ignition.
AMC Jeep 258 CID I-6 Engines From '84 to '90 Used A 'Timing Computer' To Compinsate For Advance
As Engine RPM Increased, So The Advance Ability Of The Distributor Was All But Elminated.
Trying To Tune This Ignition With Centrifugal Advance Springs Is A Waste Of Time And Resources.
In Off Road Only Vehicles You Can Change The Distributor And Defeat The 'Timing Computer'
(Commonly Called A 'John Nutter'
Bypass) To Regain Full Tunable Control Of Your Ignition Timing.
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If You Have '78 to '83 Distributor, Or Have Changed To A '78 to '83 Distributor, Then Please
Proceed...
What To Use For Replacement:
FROM: Aftermarket: Mr. Gasket, P/N 925D
Centrifugal Advance Springs, about $5.00 (usd) from
Summit Racing.
These springs DO NOT have to be installed when the upgrade is done. It is just a way to get a
little more 'zip' out of your engine.
This upgrade will bring your Jeep ignition system into the mainstream 80's technology.
3. EXTREME PERFORMANCE UPGRADE;
Once the cap, rotor, plug wires and ignition coil have been upgraded, then you can use some
racing technology in the form of.....
The next HUGE jump in ignition performance is the CAPACITIVE Discharge Ignition
(CDI)
.
All factory ignitions, and most aftermarket ignitions supposed to be upgrades for the Jeep are
still INDUCTIVE discharge ignitions (IDI), including the extremely expensive and temperamental
aftermarket ignitions that require you to buy their distributor, coil, cap, rotor, ect.
If any of these parts fail, you are at the mercy of that aftermarket company until replacment
parts can arrive (if the company is still in buisness and still making parts for your
particular ignition).
Multiple Spark Discharge (A module upgrade, from Inductive to CDI) gives vastly superior
ignition energy on all counts.
Spark Duration, Spark Voltage, and Spark Amperage are all increased to the point were misfires
are unheard of.
The MSD Capacitive discharge module driven ignition will out preform the Inductive ignitions in
all areas, from 100 to 1,000%.
MSD is the biggest bang for your bucks.
The MSD 6 series units are the workhorse of the MSD product line, and there are several
different versions of the 6 series unit available, depending on your intended application.
The MSD 6A is a full CDI unit that is more than capable of operating above 15,000 RPM with your
stock coil.
There are Weather sealed Off-Road units, and Marine units for deep water fording operations.
The MSD 6 series units are compatible with all Motorcraft distributors and ignition coils.
The most common, MSD 6 series, units are 50 State Emissions legal!
Use Wiring Adaptor P/N 8869 to connect the Motorcraft distributor connector to the MSD 6A and
6AL harness. (Around $10.)
This wiring pigtail keeps you from having to cut into the distributor wiring or the MSD wiring,
and it keeps the distributor pick up coil polarity correct.
There is one for the marine and off road units with the Weather Pack connector, but the part
number evades me right now.
If you have a later model Jeep with a 'computer', there are harnesses that will allow you to
use MSD and keep your computer functioning.
By doing just that, you stay 50 State Emissions legal with the later model Jeeps.
You can browse the MSD website at, MSD Ignition.
You can contact MSD by phone at, MSD Tech. 1-915-855-7123
If you want to learn more about MSD at this web site, CLICK HERE.
MSD hardware can be purchased at Summit Racing.
Summit Racing Equipment phone number, 1-800-230-3030.
All content and web site screw-ups are entirely mine!
