• Welcome to ClassicBroncos! - You are currently viewing the forums as a GUEST. To take advantage of all the site features, please take a moment to register. It's fast, simple and absolutely free. So please join our community today!
    If you have problems registering or can't log into your account, please contact Admin.

Finding the correct OEM 1970, 302 Distributor

wilcom

New Member
Joined
Sep 7, 2006
Messages
23
I have 1970 Bronco (california), 302 with mild RV/off road cam, manual 4 spd, Fitech carb and pertronix dist and coil. The pertronix took a dump for the 2nd time in 1.5 yrs and had to replace the flamethrower module both times. bought a new module and installed but no spark to plugs. called pertronix and they gave me all the testing specs for grounds, power , coil etc which all tested positive for ops. called pertronix and they said its the module (that i just replaced) is bad. They sent another one that they "tested" on their test bench, put that in and no spark....had it with pertronix! All of this took over a month due to pertronix bad support. Since I 4x4 in the desert a bunch I didnt want to get stranded.
So, I have had enough with electronic and decided to go back to OEM points distributor and have done with it. Now the question is what is the correct PN for that distributor.
So far I have found new or rebuilt OEM ones online but the part numbers vary. These are what I have found....
DZUZ-121227E, D0OZ-12127-VRM, D2UF-12127-CA, FD06-279 36/16. Need single vacuum.
Need help which to buy? Any suggestions for after market high "quality" dist that is not cheap china junk but made in usa.
Also, do I need the resistor block still?
The Bronco is parked in drive way at a slight slope of 15deg or so, so when reinstalling the dist with the oil pump shaft does the vehicle have to be on flat ground so the shaft can be centered and dropped in? I dont know if I can jack it up enough to be perfectly flat so would have to push it out to the street. Also read that the oil pump shaft can drop down into the oil pan if not inserted straight.

thank you in advance for any help. I live in Nevada now
 

serial car restorer

Yes, I'll restore almost anything...
Joined
Aug 27, 2024
Messages
742
Loc.
Western Oregon
I have a single vacuum dizzy that was originally for a '68 289, complete with points. Engine ran fine on it. I'd sell it for $20 plus shipping.

But full disclosure - the reason it's available is that I'm installing DuraSpark...
 
Last edited:

DirtDonk

Contributor
Bronco Guru
Joined
Nov 3, 2003
Messages
51,617
So a single vacuum, eh? I would’ve thought for sure that a 70 model from California would’ve had the dual vacuum diaphragm.
Now I wonder when exactly that started?
Pretty sure that all ‘71’s had them, whether CA or FED. And I have seen 1970 Broncos with the dual diaphragm. At least a couple of them. But they were pretty old by then, so perhaps they had been changed out at some point and dual diaphragm was all the the store had available at the time.
Hard to say without the book.

Do you have that information James? And was there a Bronco or truck specific distributor, with a “T” in the engineering number?
 

Oldtimer

Contributor
Jr. Member with Sr. moments
Joined
Feb 4, 2005
Messages
1,795
Loc.
Sunnyvale, CA
C8TF-12127-F would be my WAG based on attached PDF pages from MPC.

File to large (8.7MB), try this link, which will not last forever, so download & print.

 

DirtDonk

Contributor
Bronco Guru
Joined
Nov 3, 2003
Messages
51,617
And it doesn’t sound like they are doing a religious restoration. So it’s probably more about just getting points back.
In which case they could just order distributor for a 69 through ’73 Bronco.
Yes, the advance curves were likely different from year to year, smog and non-smog, vehicle application to vehicle application. But with the sad state of aftermarket parts being what they are, almost nobody is doing accurate reproductions. In other words, you order what you think is right, and you get what you get.
Even 30 years ago and more, every time we ordered a distributor that was supposed to have a dual vacuum can, it had a single. Every time we wanted, one with a single, it had a dual. 🙄

If you can find a company that specializes in accurate replacement distributors, right down to the number stamping on the housing, then that would be a goal. But they probably cost four times as much as a reman unit from the local parts store.

And then there’s always the self – customization route. Get what you get, and change the mechanical advance weights and springs and limiters to what you feel is the correct one. Or just the curve that you prefer.

But no matter what, you’ll probably have to deal with faulty condensers. And cheap quick wearing points.
So there’s that too…
 

Oldtimer

Contributor
Jr. Member with Sr. moments
Joined
Feb 4, 2005
Messages
1,795
Loc.
Sunnyvale, CA
69/70 U100 302 got C8TF-12127-F
which contains diaphragm coded 356, part NUMBER D2PZ 12370-L (DD-377)
which indeed is a dual diaphragm RETARDED assembly, guaranteed to make your Bronco look correct, and run like crap.

1748881285106.png





I'm going to WAG that in 1968 the non-emissions got the C8TF-A, and the emissions got the C8TF-F.
The C8TF-12127-A went in 6 cylinder engines.
68 289 came with C8TF-F or C7OF-D
 

serial car restorer

Yes, I'll restore almost anything...
Joined
Aug 27, 2024
Messages
742
Loc.
Western Oregon
Interesting stuff. The spare I have is C8OF-12127-C. Since the original 302 in my '69 was swapped out for a 289 years ago by a prior owner, I've been thinking this was probably the original distributor for the 289. Or maybe it was original to the original '69 302?
 

serial car restorer

Yes, I'll restore almost anything...
Joined
Aug 27, 2024
Messages
742
Loc.
Western Oregon
You can always validate your distributor by de-coding the date code and making sure it is correct.
Date code 7H23 (Aug 23, 1967), so almost certainly original on a '68 289. And it really doesn't matter in my case, as I don't care about originality. It has Duraspark on it now...
 
OP
OP
W

wilcom

New Member
Joined
Sep 7, 2006
Messages
23
Sorry for the late response...fell off a ladder on my back onto a 4" steel pipe. Hurts when your 72.

Holy Cow!!!! Now I am more confused as ever...thank you all for your expert help! I thought the Duraspark was the way to go earlier and I bought one at Summit racing. Took it home and sized it up but it looked way, way to big to be mounted due to its size and diameter and it would block the water temp sensor(s), radiator hose and hearer hose fitting so I took it back and decided on the points dist.
Has any one done this and can talk about clearance issues and a picture of one installed?
 

DirtDonk

Contributor
Bronco Guru
Joined
Nov 3, 2003
Messages
51,617
Are you sure it was a Dura Spark? Yes, it's larger, but no it only slightly blocks all that stuff. Just wondering if you got a typical HEI model (clone of the old GM HEI units) instead?
Did it look like the one Joe showed in Post #2? If not, got a part number for the one you got from Summit? Would like to see it, just to know.

Since temp senders are not a standard service item, and you might not have to change one for 20 years or 100,000 miles, having it blocked is not necessarily a big deal. I don't like making more work for simple tasks either, but it's not that bad.
Radiator hose? Heater hose? Never heard of anyone ever complaining about those. Are you running a stock intake manifold and fittings?

It's bigger, but it's a Ford part that was used on millions of Ford vehicles from '75 to somewhere in the mid to late '90's maybe? I don't remember when the last distributor went dead with Ford, but it was probably on a 351W in a truck. Cars used them until '96 maybe, when they changed to the 4.6 and 5.4 "Mod" motors? Trucks (and probably vans) kept the Windsor until about '96 as well.
I mentioned '75, because even though the Dura Spark came out in '74 on Broncos, it still used the small sized cap and rotor.
But rather than downgrade to that, I would still go with electronic, but swap in a small-cap "HEI" distributor from one of the aftermarket companies.

Personally, as great as they can work, I'm not a fan of the true HEI units in a Ford in general, and Broncos specifically due to the size of the cap. The ignition coil is integrated right into it, so it's even larger than most. Well, pretty much ALL other distributors.
I can't say which one might be best, because I swapped in a Dura Spark large-cap model into my '71 and my '79 already had one. And I have never had a reason to look back at anything else.

Paul
 
OP
OP
W

wilcom

New Member
Joined
Sep 7, 2006
Messages
23
The one from Summit is Summit Racing™ Blueprinted HEI Distributors SUM-850021
It is a one wire setup but the cap is way to large with the coil built in and blocks everything.

The video Joebronco73 showed in the video was just a large so I did not consider it, plus I could not find a good one in the junk yard under $200 they wanted plus it did not include the Ign module which was another $78.
But since joebronco73 showed how to replace the large cap on duraspark with small one that would be the ticket.
Now the question is;
Where to find an OEM duraspark dist and Ign module other than the junk yards. I see Cordone has one but are chinese junk.
I found this on the web; It sounds like the Duraspark I module will work with the Duraspark II distributor? Or use a GM HEI module for safety? Where can I find an OEM/NOS duraspark II dist and Duraspark I modue? If I can get a Duraspark Dist and modify it like joebronco73 said Im good.

Found this on the web;

Breakerless ignition showed up in North American Ford vehicles in 1974. The first ignitions were not called DuraSpark, they were referred to as breakerless ignitions. The modules had a green wire strain relief with two harnesses, one connecter with 3 pins, and one with 4 pins. These modules "could" vary as to which wires were grouped in which harness, so you had to be mindful when working on these cars, to make sure the person behind the parts counter gave you the right replacement.

In 1977 Ford began referring to the breakerless ignitions as DuraSpark ignitions, and released two modules simultaneously; the DuraSpark I for California, and the DuraSpark II for the rest of North America. The DuraSpark I module was capable of producing a stronger and more consistent spark under varying engine load conditions which Ford found necessary to meet California emissions standards in 1977. Both DuraSpark modules featured spark retard when starting the motor. I am uncertain if that feature was incorporated into the earlier module. Both DuraSpark modules had two harnesses, one with a two pin connector, and one with a 4 pin connector, 6 wires in total. The earlier module with the green strain relief had 7 wires, it had a blue wire that was not carried over into the DuraSpark modules.

The DuraSpark I module had a red wiring strain relief. It was a very sophisticated ignition module, sensing & controlling the currrent in the coil primary as a means of controlling the current and spark quality produced in the coil secondary. It was only installed in California cars, therefore many hot rodders were not and are still not aware of its existence, or the difference between it and the DuraSpark II module. In 1978 Ford found it could meet California emissions regulations with the less expensive DuraSpark II module in all of its motors except the 302 V8. So California cars with the 302 V8 received the DuraSpark I ignition, and California cars equipped with all other motors got the DuraSpark II ignition like the rest of North America. The same applies to 1979 California cars. 1979 I believe was the last year DuraSpark I was installed in any Ford car. Worthy of mention is the safety feature built into the DuraSpark I module; if the distributor rotor is not turning, the module shuts off current to the coil primary, the ignition cannot fire, so it is safe to work on the ignition without fear of being shocked. NOT SO with any other Ford module. Disconnecting the wrong wire on any other Ford module while you are working under the hood can result in triggering the ignition and shocking you with enough current to stop your heart.

The DuraSpark II module introduced in 1977 has a blue wiring strain relief. It is not much different from the early module with green wiring strain relief. Its reliable and provides a nice spark, but it is less sophisticated than the DuraSpark I. Current in the coil primary is controlled just like it was with a breaker point ignition, with a ballast resistance in line with power to the coil. To provide a hotter spark while starting the motor, there is a second wire supplying the coil that bypasses the ballast resistor to provide full battery voltage when the ignition key is in the start position. This module is the most common module for retro-fitting breakerless ignition to early cars, simply because many people are not aware of the existence of the DuraSpark I module, or they are not aware of the differences. Its also worth mentioning this module can kill you while you are working on the motor unless precautions are taken to avoid an accidental discharge of the ignition!

After 1977 Ford developed other ignition modules with white, brown or yellow wiring strain reliefs that have other features that are unneeded or even undesireable for retro-fitting breakerless ignition. I found in my experience with them that all of the other modules had 3 wiring harnesses. They are designed to work with input from sensors, such as knock sensors, altitude sensors, MAP sensors, etc, and they are designed to control spark timing based on those inputs, to compensate for knock, altitude, engine load, etc. Or they are designed to work in conjunction with Ford's early "EEC" engine management systems. Some of these modules were called DuraSpark II, others DuraSpark III, and beginning in 1981 there was also the "universal" module.
Some say the GM HEI module is far superior.

Installation Notes:

1. When purchasing a module for your car, buy it from Ford! The Ford manufactured modules are very reliable. Reliability of the aftermarket modules is hit or miss.

2. DuraSpark modules use a high voltage coil made specifically for DuraSpark ignition. Use the Ford DuraSpark coil or DuraSpark specific replacement. Do not use a breaker point ignition coil.

3. DurSpark coils are oil filled and must be mounted oriented vertically, with the top higher than the bottom. They must not be mounted laying horizontally.

4. Painless Wiring sells a wiring harness for DuraSpark II conversions. It should be applicable for DuraSpak I conversions too, as there is very little difference in the wiring between
the two ignitions. It is available at Summit Racing under part number PRF-30812, or JEGS under part number 764-30812.

5. DuraSpark distributors for the 351C will be sourced from a 1977 through 1982 Ford vehicle equipped with a 351M, 400 or 460 cubic inch V8.

6. A ballast resistor suitable for DuraSpark II installations is available from NAPA Auto Parts, NAPA part number ICR23 (1.2 ohms).

I have heard that the DS I with the red strain relief was a "problem child" and the other 50% say it's a good module...... go figure.

Any thoughts?
 

DirtDonk

Contributor
Bronco Guru
Joined
Nov 3, 2003
Messages
51,617
I was originally going to use a red module for my conversion. But at the time, and for a few years after, the red ones were hard to come by. Along with yellow, brown, green, black, and white. The blue modules took over everywhere and were cheaper and easier to find.
Plus, they worked perfectly fine. So that’s what everybody uses who converts to Dura spark.

Honestly, now that you’ve been going through this a lot, I wouldn’t use a Dura spark.
The wiring is more confusing than any other ignition system, so that even though for some of us, it’s not a problem, for most people it’s far too many wires.
As you found, the Hei style is far too large
I would not use a Dura spark system and go back to the small cap. FORD used the wider spaced cap for a very good reason.
Strong spark needs wider spacing. Which is why the Ford and GM distributors of the day had very large caps. They were using standard materials, so arcing was a definite possibility.
As far as I know, even replacement caps still use the old school materials. So you’re not improving anything but extra access when you go to a smaller cap.
If you do ultimately end up using Dura spark, just stick with the big cap. It’s not in the way of anything and millions of us are using them just fine

If you really don’t want the big cap, and there are plenty of people who don’t, go to an aftermarket ignition with a small cap.
Plenty of those around from MSD, Pertronix, Holley, etc.

There’s nothing wrong with points, when it comes right down to it. Nothing that is, as long as you don’t mind cleaning, adjusting, playing with, cursing at and generally maintaining them every few months.
And that doesn’t even include getting defective parts when you go to buy new.
Points and condensers are second only to the Ford starter relay in reliability complaints.
But they do run. And they’re easy to fix.
Not to mention very simple to wire.
 

Speedrdr

Contributor
Legend in my own mind
Joined
Nov 27, 2017
Messages
2,028
Loc.
Paris, MS
Sorry for the late response...fell off a ladder on my back onto a 4" steel pipe. Hurts when your 72.
Hurts when you’re 66 and you fall on your back off a porch also. Hopefully you didn’t break something important.
 

jerry

Contributor
Sr. Member
Joined
Jan 28, 2002
Messages
778
Loc.
Bakersfield, CA
I was sorry to hear you fell off the ladder too! Hope you're on the mend.

I kept the points distributor as a backup, but ended up going Duraspark in my 70.

Used: https://painlessperformance.com/product/duraspark-ii-ignition-harness-part-no-30812/ for my harness. Wanted to be able to use my older style coil, so I cut off the clip on connector and installed ring terminals. I know the pull your part would have this, but here in CA prices can be high for what you get, and slim pickings since our not-so-benevolent governor and government thinks EVs are the mandated future for all.

I ended up buying a NOS distributor rebuild from eBay. For the Duraspark 2 modules, bought two: an older refurb (eBay) and a newer (aftermarket "name brand" yet still Chinese-ium) from Summit.
 
Last edited:

DirtDonk

Contributor
Bronco Guru
Joined
Nov 3, 2003
Messages
51,617
There’s a rash of falling going on! Here, on Classic, and a couple more on another forum.
Sunday, I was backing out the door of the restaurant and found out that somebody had put a board there. I’m used to avoiding falls when going forward, but I went right over backwards carrying a couple of bags.
I made it out alive though, didn’t hit my head, but have a little road rash.
And my tailbone sure hurts!
 
Top