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76 304 TFI DuraSpark upgrade

76 304 TFI DuraSpark upgrade
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Southern Arizona
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76 CJ5 304 all stock T-150 D20 4.10 gears
Prestolite Upgrade to Duraspark Distributor & Modual on Jeep CJ

Richard,

Way to go on the upgrade of the Prestolite and use of the TEAMRUSH use of upgraded Ford Tune up parts and the Duraspark Modual and Duraspark Distributor..... I did the TeamRush and the Aux Grounds about 5 years ago and make a big difference.

TeamRush / JeepHammer
Thanks so much for valuable time and efforts in making this upgrade path known, educating jeeper far/neer on how to do it properly. U will go to jeeper heaven some day.

few thoughts

The distributor signal wires to fire are produced by the reluctor fins spinning past the coil pick up. Develops small "low level signal", mili volts and milit amps, and needs a bit of signal protection. The low level signal wires from distributor to the duraspark modual, or any igntion modual, should be twisted 2-3 turns per inch. This will cut down cross talk and other noise of Induced Currents from higher voltage & switched wires under the hood. Ignition Power to the coil, spark plug wires, even motor power wire will have magnetic flux lines around them as they turn off/on. EVERY TIME when they turn off/on the flux lines grow and collasp. Twisting means every twist will induce opposite small currents that will cancell each other or help. Keep distributor wires next to fender wall and firewall so the metal ground plane acts like a shield. Keep Distrutor wire from the coil power wires and the spark plug wires.... they are high power and switched many times per min. Add a msd and freq is now 6x the rpm since we fire 6x cylinder and much higher voltage 500v.....so even more important to keep the distributor wirs from the ignition or electric mortor wires

MSD 6 series if you find one on local swap or craigslist for as little as $35 will wire right to what you did. Give you better igntion, the duraspark modual is now a field swap back up. Change connector at distributor so fires MSD rather than Duraspark Modual, use same connector series. Cap off the Duraspark Connector with a film vial & cap & dielectric grease squeezed into conn housing. Undo the aux ground to Duraspark Modual and the D Modual will sit there at idle with NO ground ready to be used again with connector changes. Will also need another set of wires to go from the MSD to coil to fire the coil.

Battery + was pretty oxidized on the far end. Connector up up to collect moisture and oxidize more. Might want to reterminate that one, resolder, and use heatshring/w sealant. That could be lowering your amps to starter a bit.

Aux grounds....
Ignition is DC and power goes out to plugs and will go back to battery. Good GROUNDs will protect your DuraSpark Modual and make your igntiion work better. Ground both your heads with a 12-14 awg wire is a good idea to firewall if you have aux to firewall or directly to battery. I added aux grounds to block, starter, grill, firewall, dash, frame, duraspark modual.

Duraspark can be killed by:
Leaving key on RUN w/o the engine running...... constant power state causes heat build up. Potting compount in Duraspark will melt and run on fender or mtd location. Duraspark Modual is a great little igntion.... has a igntion retard during start up for easy starting. One of the reasons Duraspark has a start and run fuctions.... its for better starts. Also not all Duraspark Distribtors rebuilds will have the larger mechincal limit slots. When you get one look down the cover plate hole the limit slots will be numbered 5R, 8R, 13R, 18R and there are some more that show up at times. WE want the 13r/18r combo if you can find them. The Smaller 5r/8r are on the computer control versions 1982 & newer will not work out well w/o functioning computer and sensors and feedback carb.

Poor ground in will kill duraspark.... another reason we add aux ground

Poor ground circuit at the head or spark plug will also over work DuraSpark and cause a failure

Good Grounds make the system run much better
 
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Re: Prestolite Upgrade to Duraspark Distributor & Modual on Jeep CJ

Thank you Team Rush and MN CJ7 for the input, alway looking to learn. Team Rush you are correct, it should be just "76 AMC 304 DuraSpark upgrade". Too bad you trashed all those harnesses, would have loved to have had one! I'm really glade I did not do a cheap HEI, I always questioned if I would god one that had the wrong gear and trash my motor.

MN CJ7 , no I have not twisted the wires, I read something on that on another forum but was unable to find it again. All the ground have since been corrected since the install along with the battery cables. I had them cut back and new ends soldered on. all my ground wires have been replaced with ground cables or straps. TeamRush always beat it into people about good grounds on a Jeep, glad he did. I had thought about the MSD 6 series, I'm just so satisfied right now I hate to fix something thats working great. I will eventually get around to it. Right now I would be happy to find a resistor wire.

Cant say enough about this system, may not be the "best" system but what a hugh difference it has made!

Thanks again for the input and the time to reply! I am learning and with input like you guys have given, it make owning an old CJ more bearable!
 
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As far as 'Grounds' Go...
Electrically speaking,
You aren't driving a solid vehicle.
Every part is flying in VERY close formation, but no formal electrical contact unless you saw fit to 'Ground' your electrical loads yourself.

When I get a Jeep in here with this or that electrical complaint,
I spend about an hour adding DEDICATED GROUNDS!
Everyone is so amazed how much better the headlights work, the wipers work, the ignition works, tail lights work, ect. when it gets DEDICATED GROUNDS!

If you get the power INTO a load or device, it only makes sense to put a solid path in for the circuit to complete!

----------------

As for the Ignition, you now have a MODULAR ignition,
You can swap, change, upgrade as new and more powerful this or that comes along without starting over.

For about 90% of the guys, just getting a reasonable cap, rotor, plug wires on the vehicle makes a HUGE difference,
And it sure beats trying to GUESS if the $100 HEI clone you got off E-bay has a correct length housing, correct gear, the guy putting it together took time to tune it, or it has the correct coil, screws, center button, ect. that will keep it alive over time.

What I'm seeing more and more of is 'Red Dust' under the rotors on the 'Internet' HEIs that came with plug wires.
High resistance plug wires cook the :dung: out of the rotor, cause all kinds of ionization problmes,

If you have 'Red Dust' under the rotor, and 'Black Dust' on top the rotor,
The cheap, high resistance plug wires are causing the spark energy to blow though or around the rotor,
And they are blowing the center terminal 'Button' apart to make the 'Black Dust' on top the rotor.

That carbon is conductive, so it's a freeway for even more of the spark energy to get at the advance weights in an HEI...

Nothing beats a good set of low resistance plug wires, No matter what ignition you are running!

The MSD (not 'Street Fire') wires work really well with HEI since they are low Impedance also,
You don't loose NEARLY as much spark energy on the way to to the wire as you do with High Resistance/High Impedance plug wires.
Some of the cheap, off the shelf wires from the parts stores will loose up to 75% of the spark energy on the way to the plug!
That's just unacceptable...
 
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