DUI Cam Gear Install & Question

Title Should Be: [h=2]DUI Distributer Gear Install & Question[/h]
I suspect some one has encountered this, and I'v looked at a couple of threads. But it just didn't clarify my questions.

In between kinking fuel lines last weekend. I decided to swap out the cam gear on my new DUI distributer. Read lost of threads about how original cam gears are getting ground up when you use a new distributer and gear. So swapping it out seemed the prudent option.

The original gear and the new gear use the same shaft diameter, and the pin hole is identical. But...

The original gear and spacer washer had a .025in lash with the washer in. The new gear has a much larger lash.

New Gear, with out spacing washer


Original Gear, with out spacing washer


Both gears, new gear on the left


Have any of you done this swap? Did you have the same issue with the old gear allowing more lash? How did you rectify it?

I also seem to be having a problem - I think - of getting the distributer to sit all the way in. At least I assume it should feet all the way to the ring.

 

I think the idea is to swap it out with a bronze gear (softer metal). You've just changed gears, the material is the same.

 

Supposedly ...

If you use the original gear that has been worn-in to the cam gear, the distributor gear will not subsequently chew up the cam gear.

I ran into this problem with my reman Duraspark distributor that I used on the CJ-6. The gear from the Prestolite distributor is the same Jeep PN as the Duraspark gear, but when I swapped them over, there was a gap between the distributor body and the gear. I gave up and used the reman distributor gear that came with the new distributor.

The cam gear destruction was (from what I've read) due to a sharp-faced steel gear used on cheap HEI clones made overseas. There are some pictures here: http://junkyardgenius.com/ignition/jeep/HEIcompair.html - note this is not my personal experience - but there has been a lot of discussion of this.

If you bought one of those high-dollar DUI distributors, I'd expect it came with a quality distributor gear that won't chew up your cam gear. If you worry about it, call the DUI folks and ask them.

 

Hum for my experience if you change the distributor gear you may also want to change the cam gear too. 2 year's ago i worn out the dist gear , just change it for a new one, 3 months after the cam gear worn out too. Finally i putted a bronze gear for the distributor and an all metal cam gear. Never had issu since that.

Everywhere i looked for gear they were telling to change both at the same time.

 

Looks like the reason the dist is too high is because it has not matched the slotted key for the oil pump. You will have to rotate the engine one way or the other to align the oil pump shaft to the dist shaft. Then you will have to re-check for TDC and nr#1 cylinder firing.

 

Stick a long screwdriver down the hole and line up the oil pump shaft with the distributor. It will turn easily.

 

Ok I'll chime in on this one. It hit way to close to home not to tell my story. I just finished a frame off rebuild on our CJ6. (May2012) I had the original engine overhauled and I decided to go with a HEI Distributor. Everything seemed great when we tried to start it after two years of a rebuild, but we couldn't KEEP it running & in time. I had several neighbors help out with advice on how to set the timing. NO LUCK each time. The engine would run shortly then stop suddenly. After a two weeks playing with it. MostlyI was pulling out my hair. Finally I broke down and towed it to a shop. After acouple of hours they called and said I might want to come by and see for myself.


Well it’s what they found. The cheap HEI knock-off had chewed up the Cam gears (Beyond repair) with very little damaged to the Distributor. So...One month ago I pulled the engine out and sent it off again. Just this past week, we got it back from overhaul. They had to disassemble it and put in another camshaft. The first thing was asked was if I had used a cheap Distributor. Well that lesson cost me a lot time and heart ache and another $1500.00.


We got a real DUI Distributor this time and all seems good. Oh I still have some electrical issues but that's another story.


just my 2c

Ken Miracle

 

It's story's like this that make me glad that I chose to go the route of the large cap MC distributor with TFI. No change to the gears at all.

 

I am running a dui on my recently rebuilt 360. i did not swap gears. I am running the gear that dui installed on the dist. So far after about a year and a half I have had no problems other than the fact she winds up so fast i have to keep an eye on the tach to keep from over revving it. I have never heard of a dui dist. having problems with the gears on them just the cheap $100 units. I am very happy with mine and i plan on putting one inm y old 68 ford f100 when i put it back on the road.

 

Spent 30 minutes or so fiddling with this. Slightly rotating the oil drive shaft with a screwdriver, align distributer shaft, slide it in.... pull it back out, slightly turn one shaft... Repeat..... Never could get it to feet all the way.

This is the root of my fear Ken....

You seem not to be alone roadhog304. I caught a recent thread over on the Jeep Forum that seems to indicate that 1) That getting 'hardened' gears was an older problem, most prevalent with the cheeper HEI brands. 2) The Performance Distributers DUI unit uses the correct, or nearly correct, metal.

I did take a drill to the side of the gear, and was able to put a small divot in it. Leading me to believe that it is in fact a softer metal closer to the original. Lets hope so..

As for getting the distributer to seat properly. It took all of 1/2 minute. Eyeballed the alignment between the oil drive shaft and the distributer shaft and it slid right it. Makes me think the gear tooth alignment of the old gear is different that the gear to shaft alignment on the DUI. As long as you don't see a thread from me in the future about how my engine cratered, you can assume all went well....


Thanks again all...

 

I was reading through this thead and thought I would relate what was told to me by a neighbors son. He also installed the lesser expensive DUI distributor and within a few months ate the cam gear out of the motor. When he investigated the problem he learned that although the distributor gear has the correct number of teeth, the tooth pitch was not correct. If you look closely at your picture compairing the two distributor gears I think you will also see this.

 

Lesser expensive DUI distributor? I hope you meant HEI because a DUI distributor is one of the best on the market and has a price tag to go along with it. I paid $325 for mine.

 

To 45es, DUI is a brand, not a type. It is a GM HEI design. "Davis Unified Ignition" IIRC - a HEI clone, but apparently a well-executed one. There are cheaper HEI clones on the market, which could be what you are describing.

I wonder if your friend simply had the wrong distributor. The HEI was used on many GM engines, and those distributors will not work in an AMC engine.

Well, it's not actually a "clone" since AMCs never came with a HEI distributor. But they are a HEI design adapted to the AMC engine.

 

My bad. I realize it's an HEI. I meant to say the lesser expensive DUI clone. That said, the problem that he did find was that the lesser expensive distributor had a gear with the wrong tooth pitch even though the tooth count was correct.

 

For what its woth imho the DUI that i purchased at $300 was worth the $200 more over a generic amc hei to have it tuned to my engine and for the piece of mind that it brought be not having to worry about it having problems. I do not have deep pockets by any means but i believe in spending more the first time and not looking back. buying cheap has come back to bight me in the @$$ more than once

 

Amen, brother.

 

Just yakking here ... I'm happy that you guys are satisfied with your DUI distributors, and I understand that it is a well executed product. But...

Jeep used a distributor from 1978 on that is functionally equivalent to the GM HEI. The Duraspark distributor with the TFI-parts upgrade has the same features as the HEI design in a debatably better mechanical package.



Plus you have lots of options with the Duraspark ignition, in terms of which coil and module to run. The HEI (and DUI) is appealing to some becasue of the one-wire connection, which means you don't have to understand the ignition circuit to install the distributor. But the TFI'd Duraspark is equivalent, and IMO better.

I put together this table a while ago, so the prices are likely out of date. But it gioves you an idea of how much mixing and matching you can do with the '78 or newer OEM distributor.

 

timgr- one of the major deciding factors WAS the fact that a DUI requires just one wire. In restoring my jeep i wanted to make it as clean as possibe and it is mainly a gravel road, car show jeep. If appearances were not as important to me i would have considered using a duraspark ignition. when i build my next jeep i will likely look into it because a dui is definitly expensive.

 

Tim, based on your chart it looks as though a '78+ distributor can be swapped into an earlier 304? This seems much more economical than an aftermarket HEI model.

 

That's the whole point. The picture is my '75 CJ-6, which came with a Prestolite ignition and now has a TFI'd '78 Duraspark distributor with stealth HEI module.