Difference Between 66 and 68 Distributor

[Anonymous]

Hi All,

Okay, I may be a little paranoid but I think I've caught an error in my setup...

I have a 66 coupe, but I believe my block is a 68. The guy that rebuilt my engine told me to just order the pertronix for the '66 3.3L/200 engine (Pt. #1266). So I did, but I'm wondering now (since I now have ignition issues) if in reality I need the 68-73 Ignitor Part No. 1261. It seems the main difference is the distributor between the 65-67 dizzy's and the 68-73 dizzy's.

How can I tell which exact distributor I have? I know that mine has a single diaphram.

 

[Anonymous]

As I understand it, the real difference in ignitors is how the magnetic sleeve fits over the shaft. If you have the wrong one it won't fit at all. So if the sleeve fits ok then you should be fine. An ignitor is just like a set of points that opens and closes. There's really not too much to it. Although I prefer points cause my ignitors sucked and I pulled em off my car.

-Dan in Atlanta

 

[Anonymous]

Dan,

Thanks for the reply...I was told by my local shop that points worked just fine (well, i guess they had to at one point) but IF the pertronix/or other electronic ignitions performed correctly, they will give better overall performance. Anyway, He says I might as well go back to points...I'm pondering this idea...

Do you know if my Flamethrower coil will be too much for the points? Or will I have to go to a stock coil??

Have you noticed any adverse affects from switching back (assuming your pertronix worked at one point)?

This car is ultimately going to remain a daily driver for some time...

 

[66 Fastback]

You need to read the sticky's a the top of this forum regarding the spark control valve and the pre-1968 distributrors. If you do have a '66 distributor, then you need a spark cocntrol valve equipped carburetor for the '66 distributor to work properly. And if the distributor and carb are compatible, you need to check the vacuum motor on the distributor to see that it is not leaking and that it is actuating the distributor properly.

These are likely the source of your ignition problems if you have a "mutt" of a engine with various components from several years.
Doug

 

[CZLN6]

Howdy Marvista and All:

1st some info- Both the pre-'68 and '68 to DuraSpark are point type distributors.

The Pre '68 has a complex, load sensitive vacuum actuated advance system built into it. It starts with a modified vacuum signal from the carb through the Spark Control Valve, to a specific vacuum cannister and on into the advance system of springs and eccentrics that manipulate the advance plate under the points plate. FoMoCo liked this system because it is cheaper to produce, and when working as designed worked fairly well.

The post '68 is a true dual advance system, meaning that advance is achieved by both centrifugal (aka mechanical) and vacuum advance. The centrifugal advance is controlled by a system of springs and weights that actuate the advance plate. The vacuum advance system begines with a ported vacuum signal from the carb to a vacuum cannister to the advance plate. The centrifugal function helps performance, the vacuum function helps economy.

A true dual advance distributor should not be confused with a vacuum advance/retard distributor found on some Post '68 distributors.

As Dan has said, if the Petronix unit fits over the distributor shaft, it should work. If the Petronix unit is working as designed it is better than points in at least two ways- no more points to wear out and reset, and a stronger more precise spark to the plugs. And a wider plug gap. With the Petronix usit you should notice a smoother idle, quicker starting, and slightly better economy.

The Flamethrower coil should work just fine with points, although it may cause them to burn and/or wear faster.

Hope that helps.

Adios, David

 

[Anonymous]

I assume the Flamethrower is a 12 V coil. In order to fully utilize it you will need to bypass the pink resistor wire that is used in series between the ignition switch and the stock coil. You should run a full 12V to the coil. If you are running the ignitor it will also want 12V. If you are running points you should run a 1.3-1.4 Ohm ballast resistor between the coil +12V side of the coil and the points to keep the points from burning up as quickly.

-Dan

 

[Anonymous]

I currently do not have a ballast resistor. as a matter of fact, i never did even with points and the stock coil. at most, i will have the flamethrower (w/a 12 v source) hooked up w/points for maybe a couple weeks. Unless this will cause me drivability issues then i'm okay, because within a couple weeks i'll either have gone to Duraspark or another pertronix unit.

Speaking of, Pertronix tech support told me today "our units aren't intermittent, they're either fail or no fail....if you return it to us, we'll test it or send you a new one." Funny because i believe my unit is intermittent and other shops have confirmed this.

I was already ordering Duraspark parts online when I called Jon from PONY CARBS to ask about cloggin the SCV when he told me "DO NOT GO TO DURASPARK. IT IS BAD FOR THE DISTRIBUTOR CURVE - IT IS A BAD SWITCH!" For the life of me, I can't remember exactly why he said the duraspark would harm the curve or anything else but he seemed quite opposed to the idea...he likes the Pertronix units (when they work!).

Who knows, maybe I'll end up back at points for the interim!!!!

 

[Anonymous]

So i was reading a book dedicated entirely to ignition systems and they show one popular set up of running a points distributor with the assistance of an MSD6A CD unit...the theory is that you get an increased spark and better performance, less wear on the points because they are assisted with the MSD unit, not to mention, if the MSD unit fails, you can simply bypass it in a matter of minutes...I'm just wondering if this might be a good route for me to go...


i'm sick of debating the different options (pertronix/points/duraspark) in my head, but I've just heard good and bad things about all of these systems - all I want to do is have a RELIABLE ignition system!!

 

[addo]

How many people have gone from DS-II back to points?

How many people have fitted a Perchronix and then gone back to points?

I can't enumerate any for the first category. That may reflect my opinion!

Regards, Adam.

 

[simon]

How many people have gone from DS-II back to points?

*raises hand*

 

[addo]

I'll just get my couch and notepad.

So, why was this decision taken?

 

[simon]

didn´t look period correct, and I had an ugly box cluttering up (!) my engine compartment...

also, the spark box doesn´t satisfy my aquisitive desires to control and manipulate. Ever hollered at some integrated circuits? No relieve, not even a bit. Mechanical components are so much more rewarding to blaim.

now, is that a sign of insecurity?

 

[CZLN6]

Howdy All:

Sorry for the worry to your head Marvista, but progress doesn't come easily.

I respect Jon at Pony immensely, but IF he's ditzing the DuraSparkII for a mis-match of curve, consider this- He may have been talking about the vacuum signal from an 1100 with SCV to a DS II. If so, He's right. These two are designed for different partners.

Consider that FoMoCo went to DS in '74 and DS II in '75. They didn't do it because it was cheaper. Clearly, in is a better system than your Points in a Load-a-matic Distributor.

IF you want a period correct appearance then go with the petronix or a DS with the small cap and rotor. If you are as purist as Simon, you can hide the module under the factory windsheild washer bag.

Yes, the MSD CD unit is a good support for an OEM point system.

Progress comes at a cost, and not just money.

Adios, David

 

[66 Fastback]

I have the MSD box triggered by a points distributor with Pertronix in the Mustang. However, I installed a '68+ distributor to be compatible with other carbs that do not have an SCV.
FWIW, I also have another vehicle with the points triggering the MSD.
Doug

 

[Anonymous]

David,

I've made up my mind - I will be purchasing an A1 Cardone Rebuilt Distributor for a '79 fairmont with a Borg Warner Module, Corresponding cap, rotor, wires, and adaptor from my (non chain) local shop for less than anywhere on line...

I'm in the neighborhood for a rebuild on the autolite 1100. I was planning on doing it myself...

As far as plugging the SCV valve on the 1100, am i (considering i'm in the neighborhood for a rebuild) better off finding a different/more compatible carb for the DSII? If so, what do you suggest?

I have your book ordered as a bday gift for myself next week - Can't wait for it to come but I'm looking to make this switch this wknd!!!

Thanks,
Jeff

 

[red(neck+truck)]

i was the only person in my highschool autoshop that could propperly set up a point set. the reason..... points suck so y learn to set them up instead convert to something that doesnt sear out as much and works better

 

[CZLN6]

Congratulation Marvista:

Excellent choice. I don't think you'll be disappointed in the improvement over your current point system.

As far as an appropriate carb, you have to possibilities;
1. Modify your current 1100 with the SCV, by modifying it. 1st verify that it has a 1.20" venturi. If it does not, don't go any farther. If it is your original '66 carb you should be ok. As for the SCV simple unscrew it from the carb body and find an appropriate bolt with which to plug it. Tap a manifold vacuum source and use that as a vacuum source to the carb cvacuum advance system. Be careful with initial advance settings. Don't overdoe it or you'll likely have too much advance at highway cruise speeds with full manifold vacuum.
2 find an Autolite 1100 from a '69 mustang with a 250. It will bolt up to your linkage and allow you to use a stock air cleaner. The stock gas line is in the same place too. You may need to bevel the edges of the carb hole to allow the larger butterfly to operate. This carb has a ported vacuum source that is compatible with your DS II. This is my first choice for your situation.

Another option would be a Carter YF from 1970 and later 200s, but they used a throttle cable linakge system, a different gas line set up and air cleaner.

What will you do?/??? The adventure continues. Keep us posted.

Stay tuned.

Adios, David