Aftermarket ignition

[Soren Johnson]

Is there any aftermarket ignition for Deville -72 to make an upgrade to (don't know the word) "pointless ignition"?
I hope you all understand what I'm looking for 

[TJ Hopland]

The HEI systems that came stock starting around 74-80 will fit in the motor and parts are the same as other Gm's of the era.   Possible issue is the older motors used a dual AC PS belt setup that I understand can rub on the side of the distributor cap depending on how the timing is set.    I have seen several motors running just a single belt with no problems.  My car is that way and has been for 9 years but I dont have the AC in so that may lessen the load on the single belt. There were different pulleys with a larger single belt that were used on the cars that came with the HEI's from the factory. The later the dizzy model the worse the curves tend to be for performance.  Anything other than your original is probably not going to have the best curve including a 'direct fit rebuilt' unit.   Even your factory one could be tweaked for a little performance if you knew what to do.

The other option is a conversion kit to your existing dizzy.   Pertronix Igniter I is by far the most popular kit and had been around the longest.  I have been told if there is a 'factory' option for your  engine you are best to go with that but if there is not one or you want to keep the stock look the Pertronix is the next best thing.

MSD and other companies make complete distributors also but have your credit card ready.

[mario]

you can also check this out:

http://www.davessmallbodyheis.com/

i have one on my 500 and it hasn't skipped a beat yet. 5 years, not cheap though.

ciao,
mario

[TJ Hopland]

Here is a shot of the later single belt design, you can see how close the belt comes to the side of the distributor.


Here is the best shot I have of the dual belt setup.  This car does not have the AC so the belt runs direct down to the crank.  You can see that the inner belt would be an issue if it was there and went up to the  AC.

[Otto Skorzeny]

From personal experience I would recommend the GM HEI setup from a '74 with the same engine. I had a '72 converted from points to a '74 HEI and it worked very well. They're also reletively inexpensive as compared with the Pertronix system. Another plus is the "bolt right in" factor. You can see how things are supposed to be in the service manual. One problem with the early HEI systems is that the module is prone to failure if it gets too hot.

I currently drive a '56 with points. I drive thousands of miles a year and take trips of over one thousand miles regularly and have never had trouble with distributor point ignition. If you keep things in order they will work without any trouble. If they do act up you can generally make the necessary adjustment and be on your way.

The solid state systems either work or they don't. There is no middle ground. You're more likely to be left stranded by an HEI failure than you are with a point problem.

[TJ Hopland]

Otto, how did you deal with the belt clearance issue on the 72?

[Otto Skorzeny]

I don't remember having a problem so I don't remember specifically doing anything to alleviate it. On the '74 and later models, did Cadillac use different pulleys or spacers or something? I know I didn't change the whole front end of the engine but I know I didn't have parts being rubbed by belts.

[TJ Hopland]

When they went to the HEI the changed to a single slightly wider belt for the AC and PS. The earlier models use dual belts.

Do you remember if your 72 still had both belts and the AC still hooked up?   There was also additional belts for the alternator and smog pumps but they go the other way.

 

[Big Fins]

I did this changeover on my '70 deVille Convertible. I installed a 1975 HEI dizzy system.

Now for the belt clearence issues, standard belt width was a "17" series belt, which was wide and rode right on top of the A/C and P/S pulleys. If kept really tight there was no issue. But if you went to a "15" series belt, this was a narrower belt and gave a nice clearence gap in between the belts and the cap.

Another way which I don't recommend unless you know what your doing is to move the physical cap and distributor clockwise (As you would be advancing the base timing) to keep the screw holddown towers from being hit by the belts and moving the wires one hole counter clock-wise.
I hold no liability to anyone using this method. But it will work.

Fins

[TJ Hopland]

Fins, In my above picture (chrome air cleaner & brown cap) it would be the screw in the 6 o'clock position that could be the problem?   I just looked on that car and that mounting screw does not stick out any farther than the other bumps.   In that orientation (and if that was an earlier 472/500) a dual belt setup should work especially if you went to the slightly narrower belts?

A little grinding in the right places to add more mechanical advance and a washer to limit the vacuum advance can really wake these motors up.  Timing must have been one of the ways they made these engines meet emissions.

[Otto Skorzeny]

Hi TJH,

Sorry it took so long to reply. I honestly don't remember if I removed one of the belts or not. It doesn't sound like something I would have done, though.  Big Fins' suggestion about the timing is one that I was going to make but decided against. It is a perfectly acceptable way around the clearance issue. I'd try changing belt sizes first.

Big Fins, I noticed the little picture by your post shows your car in front of what looks like a big ficus tree. That looks like the tree that the luvdg guy in Florida poses his cars in front of. Did you get your car from him? Just curious/nosy.

Forrest

[STDog]

Big Fins, I noticed the little picture by your post shows your car in front of what looks like a big ficus tree. That looks like the tree that the luvdg guy in Florida poses his cars in front of. Did you get your car from him? Just curious/nosy.

I know that he did not buy the car from luvdg.

[Big Fins]

No, I didn't buy the car from Luvdg. But that is his tree. It sits behind a group of warehouses, where he does some of his car work. He has a couple of warehouse/showrooms, within a mile of where I live.

My car wanted to pose under the tree for fun!! 

Fins

[Otto Skorzeny]

That's funny!

[jaxops]

I used a Pertronix electric ignition and it burnt out trying to get it to work.  Definitely don't go cheap if you are converting these things.  This unit was not exactly cheap but you had to use washers to adjust the gap....which never quite adjusted nor ran properly.

[35-709]

I used Pertronix ignitions on 2 different '66 Cadillac engines and was very happy with the results.  The instructions on the units I used made it clear there was no gap adjustment to be made and that none should be attempted.