DUI

[comet the dog]

I think im gunna go get two, one in each jeep. Davis Unified Ignition that is. What are your opinions and experiences with these distributors? Easy install? Will i be able to eliminate a bunch of those Expletive Deleted!Expletive Deleted!Expletive Deleted!Expletive Deleted! wires that run back and forth, to and fro, left and right in the engine bay? Ive owned two fsj now for two years give or take and have already become frustrated with the stock electronic module refusing to cooperate.
Whadda ya guys think? Is there a better option? Im currently rebuilding a 360 that will have a mild cam, performer intake and edelbrock carb.

[conehead]

I have installed three of them and they work well and do clean up the engine compartment. The only issue is that it is a large unit so getting the clearance from the power steering unit, plug wires, and water pump hose so you get enough room to move it for timing can be tricky.

[hookedup50]

X2 on clearance issues, but workable. I've had one since 2000 and has been trouble free. There are cheaper units out there that do same thing. Someone else can chime in as to quality. I've gotten my moneys worth out of my DUI unit, but they are overpriced IMO. There were not as many options back then, or I was not as internet savvy back then.

[tgreese]

I don't see what the appeal is for the HEI distributors. The wiring for the ignition is very simple, and the factory Motorcraft Duraspark distributor functions in exactly the same way as the HEI. You can even combine parts from Duraspark and HEI in the same car - Google "Stealth HEI."

What year is your Jeep? Anything '78 or later has the Duraspark distributor, and I see no clear advantage to swapping in a HEI for a Duraspark. Basically they are the Ford and GM version of the same ignition system. And you can argue that the HEI has some issues that go along with stuffing the coil under the distributor cap. Not great IMO.

[j2sax]

While I agree to some degree, if you do not see a clear advantage for the HEI, you may lack the experience of so many with the MC system.

The "simple wiring" is 30-40 years old and it runs right across the intake where it is often pretty crispy... a lot of resistance and other issues can occur there.

The HEI offers a brand new dist body and wiring and, in reality, under 6000 RPM, there are few issues with anything under the cap. The metal screws that can be changed out for plastic ones fixes many issues over 6000 RPM.

The coil is NOT UNDER the cap... the area under the cap where spark is generated is COMPLETELY isolated from the coil chamber other than the electrode that transmits the spark to the rotor. This also eliminates the coil wire and the loss of energy that can occur over that span.

The MC Ignition Modules are a main issue with their high failure rate. The HEI module under the cap still has a much better longevity than the MC Module. IF you want to carry an extra module, you could put it in your pocket or ashtray, much less room required in the glovebox!

Throw on the "e-core" coil and you can eliminate the reduction wire that reduces ignition power. Even at it's best, the MC system throws down about 15K volts... the HEI or the MC/HEI/E-core Hybrid systems will triple that. This is my preferred system as I take the distributor wires off the intake and move the "Stealth" module to driver fender, ( I do not go "Stealth" though and just mount the Module on a heatsink) and mount the coil on the fender as well. That way it eliminates most of the wiring from off the intake and makes it a lot easier to work on and is easier on the wiring for the long haul. So, far, in many years of running this setup on multiple Jeeps and AMC's I have yet to need to replace a module.

This is not the "same" system by any stretch, though all ignition systems do the same essential job.

[tgreese]

While I agree to some degree, if you do not see a clear advantage for the HEI, you may lack the experience of so many with the MC system.

The "simple wiring" is 30-40 years old and it runs right across the intake where it is often pretty crispy... a lot of resistance and other issues can occur there.

The HEI offers a brand new dist body and wiring and, in reality, under 6000 RPM, there are few issues with anything under the cap. The metal screws that can be changed out for plastic ones fixes many issues over 6000 RPM.

The coil is NOT UNDER the cap... the area under the cap where spark is generated is COMPLETELY isolated from the coil chamber other than the electrode that transmits the spark to the rotor. This also eliminates the coil wire and the loss of energy that can occur over that span.

The MC Ignition Modules are a main issue with their high failure rate. The HEI module under the cap still has a much better longevity than the MC Module. IF you want to carry an extra module, you could put it in your pocket or ashtray, much less room required in the glovebox!

Throw on the "e-core" coil and you can eliminate the reduction wire that reduces ignition power. Even at it's best, the MC system throws down about 15K volts... the HEI or the MC/HEI/E-core Hybrid systems will triple that. This is my preferred system as I take the distributor wires off the intake and move the "Stealth" module to driver fender, ( I do not go "Stealth" though and just mount the Module on a heatsink) and mount the coil on the fender as well. That way it eliminates most of the wiring from off the intake and makes it a lot easier to work on and is easier on the wiring for the long haul. So, far, in many years of running this setup on multiple Jeeps and AMC's I have yet to need to replace a module.

This is not the "same" system by any stretch, though all ignition systems do the same essential job.

For the most part, I'm in agreement with you. The factory Duraspark I system is essentially the earlier points ignition with electronic switching.

The usual complaint about the Motorcraft ignition cites the unreliable module. It is my understanding that the factory Motorcraft modules are quite reliable until they are say 30 years old, and that the replacement modules are not of equal quality. I would guess that a module from Standard (SMP) or Airtex would be of comparable quality to the original, but I have no experience with those. Whatever module is in my '82 runs strong ... maybe it's OEM.

My CJ-6 is running the Motorcraft distributor with a HEI module and a Pertronix coil. It too runs fine ...

I agree that the pluggage and socketage on the Duraspark sucks ... but you can replace it if you want to. A new pickup comes with a new plug, and the female side is available from MSD or otherwise from aftermarket. Ideally you'd replace the crappy plug/socket with a weatherpack connector, but I have not tried it.

The HEI is not a bad distributor, but it's just not much different from the Motorcraft. Use the big cap, HEI wires, an EI coil, and you've got the same thing as the HEI package. Why spend hundreds of dollars on a work-alike DUI distributor, when you can use what you've got?

[Carnuck]

Hundreds? I got mine new for $85 complete with coil in cap and got the tuneup parts at the same time.

[j2sax]

DUI/HEI/Hybird

Carnuck, you must have the "Skip White" HEI as the DUI HEI is generally more expensive than $85. I have heard great things about the quality of the Skip White version.

I also agree about the connectors... I always upgrade to Weather Packs on just about everything! You have to buy special crimping tool and the connectors are more than spades, but it is SO clean, well protected and re-useable.

Though we are talking about the distributor connector here, you can see the differences in the 89-91 MC Module connectors here with Weather Packs:

http://www.stockwiseauto.com/images/products/SMP/LX235.jpg

and the older, nasty, hard to disconnect-easy to break factory connectors:

http://www.quadratec.com/Assets/Images/5544/5544-lg.jpg

I forgot to mention that with the "Hybrid" system, you can also upgrade to the "Big Cap" with much better PLug Wires, which, though larger than stock, fits better than the HEI.

Not knocking the HEI conversion here either! Just explaining some options!

Jesse

[Carnuck]

I don't knock either one, but running 40 year old coils seem to be asking for failure. Spark from TFI, HEI or even just a regular electronic ignition system makes it run better.

[autogatto]

DUIs quality has gone down quite a bit in the past few years with failing components.

Talking about my personal experience and the one of a friend on two twin built 304s on two rockcrawling CJ7s, we both had the body of the distributor to literally get chewed up by the washer that is located between the body of the dizzy and the cam gear thus resulting in the shaft moving up and pushing the rotor against the cap till everything stopped working.

And I also heard of more than one failure of the coil.

Still it's a decent product even if probably overpriced. Do a little research on the web if you find more problems reported with these units.

[Gurinski]

I thought you got busted driving under the influence

[wdbill]

I just did the TFI/HEI stealth with a new dizzy and all new wires.