Electronic Ignition 74 CJ5

I have been reading this forum for a few weeks now and find myself addicted, checking at noon (from the office) and in the evening (from home) to check the new submissions. So now I have a question for the group. I have become the sole provider and means of support for a '74 CJ5. It has an inline 6 that runs smooth. I believe the transmission is a T18 and not a T18a. Now that the tax refund is here, I am prepared to spend some dough on an electronic ignition system upgrade. I have been advised to deep 6 the points and condensor and upgrade with EI. Herein lies the confusion. I see Pertronix, DUI and MSD mentioned in terms of upgrades. What is preferred for my CJ5? Is the install as easy as it appears?

Secondly - Is there a parts list available regarding a front disk brake conversion for a Dana 30? I want to do the conversion, think I have access to parts, just need to know which ones work best.

Any assistance is appreciated.

 

GM HEI works well for the 258. Can be done with scrounged parts or bought complete. http://www.4x4wire.com/jeep/tech/electrical/hei02/ Another possibility is the TFI upgrade for a stock Motorcraft ignition, '78 or later. http://keith.cj8.tripod.com/tfi_upgrade.htm

Both would be cheaper than the DUI or MSD. The Pertronix is an add-on for the stock distributor AFAIK.

The GM HEI is reputed to be the most reliable, and uses cheap and available Chevy ignition parts.

 

Another welcome from Pittsburgh, PA!

I love my DUI. Yes, you can do it cheaper by doing the GM HEI, but I liked the warranty I got...

 

Thanks for the prompt responses and reference materials. Despite the expense, I am leaning toward the DUI. Upon installation I will give a report. After 1 year of ownership I have put on a 4" lift, roll cage, BFG M/T 33"s, new seats, paint (for the spouse) and am installing an oil filter re-locator in light of a small problem during my 2nd off road trip. Other than the front disks and HEI, any further upgrade recommendations?

 

These folks (formerly Cape Conversions) sell the GM HEI complete: http://www.driveajeep.com/index.html

 

As for the front disc brake conversion, I got a front rear from a 79 cj7 (same dana 30 axle width, probably different gear ratios, but i swapped them out for 4.88s) and just swapped the whole thing. The whole thing went in pretty smoothly.

 

I may be banished from the halls of the buy-new-jeep-parts club for saying this, but I've been running a standard points ignition on my '74 for about 3 years. 2 years as a daily driver and now just as a weekend-around-town vehicle and offroad truck. Works fine. I've thought about the HEI setups, and the MSD (the multi/long spark deal seems appealing), but since I don't put a huge number of miles on the truck, I figured why bother. The stock ignition (new cap/rotor/points/plugs/condenser/wires) installed, setup and timed could be all you need -- and cheap!

 

I had a few questions regarding the electronic ignition upgrade. Has anyone here done it on the 304? I just reciently got mine running smoothly again, and I want to get rid of the points. Anyone have any suggestions?

 

Cheapest would be the Motorcraft ignition from a 360 full-size Wagoneer; get the ignition box, the distributor complete, and the under-hood harness. Then upgrade to the TFI (thick film integration? something like that) parts. There are lots of links on the web if you search for TFI and Jeep.

 

The JU link is good, but they are discussing adding the TFI parts to the existing late 304 Motorcraft ignition. Jeeps went from points ignition, to Prestolite electronic ignition in 1975 (avoid!), and then to Motorcraft electronic ignition in 1978. The Motorcraft ignition in '78 and later Jeeps uses the standard size distributor cap and a conventional oil-filled cylindrical "volcano" coil.

The TFI stuff is an upgrade to the OEM Motorcraft "DuraSpark" setup. The TFI coil is different, as are the wires, rotor and distributor cap. You also need an adapter that fits on top of the distributor that accomodates the larger cap.

The article on JU may give you the impression that you can drop a Ford DuraSpark distributor into a 304 - AFAIK you cannot, without machining the housing and changing the distributor gear. The sensible way to do this is to get the stock Motorcraft parts from a 360 and add the DuraSpark/TFI stuff to upgrade to the better standard. I suggest a 360 Wagoneer because the 360 parts are the same and you're much more likely to find a 360 (Grand) Wagoneer in a wrecking yard or pick-your-part than a CJ with a 304 and Motorcraft ignition.

Jeep could have gone with the TFI upgrade when they sold these vehicles - for some reason they chose the cheaper grade of parts. Maybe just cheapnis on their part.

I'll find some good links.

 

Here's a good link: http://www.buildyour4x4.com/BY-Tech/Presto-Moto01.html

This explains how to change from Prestolite to Motorcraft (DuraSpark); changing from points ignition will be similar. There's also a link on this page that goes through the TFI upgrade for DuraSpark.

<edit> If you come across electronic ignition in a Jeep vehicle that uses a distributor with a PLASTIC vacuum advance, that's a Prestolite system. Leave it there, you don't want it.

 

I have never used one in a jeep yet, but have used pertronix modules instead of points in 4 other classic cars. they are about $80 go in with a screw driver and 5 minutes time and seem to be very reliable and do not require the adjustment like points would.

 

http://www.jegs.com/cgi-bin/ncommerce3/ProductDisplay?prrfnbr=4414&prmenbr=361

What about this kit? Do you think you can go TFI cheaper on a 304?

Petronix Ignitor II Kit. $110. Dunno.

 

When you add up all the pieces, probably not. The Pertronix would retain your cap, wires, rotor and distributor. You'd want to buy the cap, wires and rotor new for a TFI system. Even DuraSpark would probably be more expensive, since you'd still want to use a new cap, rotor and wires when you install the used distributor.

The centerpiece of the TFI upgrade is the coil, which requires the new wires and larger diameter cap (to prevent arc-over). You keep your old coil with the Pertronix, so that's an advantage of the TFI that you would not get.

 

I know a lot of guys around here seem to like the Pertronix, but it didn't work out too well for me. I installed it and it ran fine for a couple of weeks, but then it died one day. I had been working on rewiring the jeep, and did a lot of jumping in and out with the key on checking circuits. The answer i got from tech support was that sometimes if you leave the key on without the engine running it will burn up the Pertronix pieces. This worried me as owners of 30+ year old vehicles are likely spend a great deal of time trouble shooting wiring issues.

I pulled it out and went with a DUI and have been happy ever since. It was a lot of money, but the "one wire" simplicity appealed to me. I think that given the option, I would keep the stock system over the Pertronix. Maybe not as smooth, but "peace of mind" and all that...

Just my 1.5 cents,

Jon