Duraspark II with ram air debacle

[351mach1]

My new to me 71 Mach 1 with 351c has a mish-mash of parts that I am trying to sort out. At some point a Duraspark was installed on this vehicle (best guess is out of a 74 Gran Torino along with the engine.) I was having running issues with the engine so I wanted to replace the whole ignition and start fresh. I was able to source all brand new parts from NPD except for the correct distributor. The issue I am having is that the currently installed distributor has the female plug cap that fits under the Ram Air where as all the "remanufactured" distributors from 74+ vehicles have the large 2 piece caps with male connections. The female plug cap does not fit on the distributors with male plugs (see end of this post). Also, all the "remanufactured" distributors from online and local parts store appear to be CRAP (Chinese Replacement Auto Parts).

For visual comparison:
Large Male Duraspark Dizzy: https://www.autozone.com/external-e...r-bdlg-fd03/193720_0_0?searchText=distributor

Correct size female Dizzy (without Duraspark): https://www.autozone.com/external-e...r-bdlg-fd15/193895_0_0?searchText=distributor

Questions:
1: Where can I source a new/refurbished Motorcraft duraspark distributor that fits the smaller, female plug distributor cap? (the female plug cap is the same for 71-73 351c with points)
1A: Is the easiest solution here to buy the points distributor and convert it to Duraspark?
2: What is the correct rotor for this distributor? (see photo below)
3: Where is the ballast resistor in the wiring harness? (I took the whole dash apart and cant find anything that resembles a ballast resistor you would purchase online)
4: Where do I find 12V "ignition on"
5: What engine wiring harness do I need with this 4 pin connector from the firewall? (the harness I bought from NPD only has a three prong plug)

Pictures:
The "tang" on the new rotor doesnt engage fully with the distributor


These are the plugs I have coming from the firewall. The pink wire is connected to 6.5V so that goes to the ballast resistor wherever its hiding. None of the other contacts show voltage


The 71 engine wiring harness I bought from NPD only has 3 contacts:



Notes:
-The Ignition Box I purchased from NPD is Chinese. Online reviews says the chinese Duraspark boxs are junk (big surprise). I bought it from NPD hoping it would be higher quality.

Helpful threads:
https://7173mustangs.com/threads/distributor-issue.45203/#post-455833
https://7173mustangs.com/threads/adjusting-rotor-phase-on-duraspark-distributor.45372/

From above thread: "One thing people should know about the Cardone....the housing OD, where the cap seats, is larger than a Motorcraft. In other words, you have to use their small to large cap adapter. I learned that when I tried to fit a small diameter HV cap and it wouldn't fit.....I ended up turning down the housing and use a Motorcraft adapter now. I bought it for its 10L advance plate."

 

[71coop]

I ran into the size issue with a Cardone dizzy and the small female cap - initially I just dremeled out a very thin layer around the inside of the plastic cap to get it to fit. A year or so later, I needed to replace the older cap and the replacement caps fit perfectly, so there must be some variation in size in reproduction caps.

If you want to go with a small male cap, I also found this video not long ago that presented another option. Not sure if that will fit with the ram air breather assembly, though - it would at least be very tight.

On the ignition box, I have actually never had a problem with the cheaper repro imported version, so take that for what it's worth.

 

[TheRktmn]

The 75 Ford Granada 302 used the small Duraspark cap and rotor.

 

[71coop]

will that fit a 351c?

 

[Sheriff41]

This is an option: https://www.amazon.com/dp/B000C7XPX...4HN2IACZ&psc=1&ref_=list_c_wl_lv_ov_lig_dp_it

 

[Stanglover]

You've probably seen mine and Sheriff41's reply in you previous post with suggestions where to buy a DuraSpark system. Maybe either of them can supply what you need.

 

[rvrtrash]

The pink wire is a resistance wire. There isn't a separate resistor. I think just the portion under the dash is the special resistance wire, and the engine compartment side is a standard wire.

 

[basstrix]

I ran into the size issue with a Cardone dizzy and the small female cap - initially I just dremeled out a very thin layer around the inside of the plastic cap to get it to fit. A year or so later, I needed to replace the older cap and the replacement caps fit perfectly, so there must be some variation in size in reproduction caps.

If you want to go with a small male cap, I also found this video not long ago that presented another option. Not sure if that will fit with the ram air breather assembly, though - it would at least be very tight.

On the ignition box, I have actually never had a problem with the cheaper repro imported version, so take that for what it's worth.

I had a similar experience with a Cardone brand Duraspark distributor. The distributor housing, where the cap fits, is slightly larger OD as compared to an OEM Duraspark. The adapter ring (for the large diameter cap) from my OEM duraspark would not fit the Cardone, nor would a small diameter distributor cap. I used a belt grinder to turn down the OD so that I could use OEM caps and adapters on the Cardone.

 

[Stanglover]

I had a similar experience with a Cardone brand Duraspark distributor. The distributor housing, where the cap fits, is slightly larger OD as compared to an OEM Duraspark. The adapter ring (for the large diameter cap) from my OEM duraspark would not fit the Cardone, nor would a small diameter distributor cap. I used a belt grinder to turn down the OD so that I could use OEM caps and adapters on the Cardone.

I bought a Cardone stock style 351C distributor awhile back and found it was made in China so it was all metric. Possibly the one you got was a Chinese metric casting which might be a bit different if they didn't do a correct conversion.
I never used the Chinese one, still in my junk box.

 

[basstrix]

I bought a Cardone stock style 351C distributor awhile back and found it was made in China so it was all metric. Possibly the one you got was a Chinese metric casting which might be a bit different if they didn't do a correct conversion.
I never used the Chinese one, still in my junk box.

The adapter that came with the Cardone distributor is sized to the housing. It fits loose on OEM duraspark. I'm confident the size is intentional. I'm not a fan of the chinese knock-offs, but it was an easy way to get a 10L advance plate. One thing I like is how easy the advance plate comes off. Just a screw....not that horseshoe "dammit" clip that's such a PITA to R&R.

 

[351mach1]

@Stanglover answered in my other thread but this lead looks very promising: https://performancedistributors.com...-460-1969-1981&attribute_pa_color-choice=blue

While cruising Craigslist I found a MSD 8577 distributor for $100. Maybe that distributor with this cap would also do the trick?
https://www.summitracing.com/parts/...iNG15wAkQw8NdIbKUljhOj7PsE4eJcoBoCs5IQAvD_BwE

Anyone have any reason to steer clear of MSD distributors?

Edit: description says: "Supplied with small diameter cap with HEI style terminals and race rotor"
"Billet housing is 5/8” smaller in diameter than stock Ford distributors"

Also the 8577 doesnt have a vacuum advance

 

[Stanglover]

The adapter that came with the Cardone distributor is sized to the housing. It fits loose on OEM duraspark. I'm confident the size is intentional. I'm not a fan of the chinese knock-offs, but it was an easy way to get a 10L advance plate. One thing I like is how easy the advance plate comes off. Just a screw....not that horseshoe "dammit" clip that's such a PITA to R&R.

That's interesting. Being able to remove or replace plates easily is a bonus and the 10L is what you need to give 14-16 degrees of initial timing.
Another part on the Chinese distributor I bought that caused me some concern was the quality of the gear. Cardone said it was made to OEM spec, but was it??

 

[351mach1]

Cardone said it was made to OEM spec, but was it?

Something I learned from the Volkswagen Diesel world is to never trust Chinese parts. Guys were blowing engines left and right trusting Chinese fuel injectors, fuel pumps, water pumps, all sorts of things. It seemed like as soon as you put a Chinese part on, disaster was right around the corner.

I like having nice things and I will always choose quality. It sickens me to see all the low quality stuff coming from China and going straight into the trash (not just car parts)

 

[Stanglover]

Something I learned from the Volkswagen Diesel world is to never trust Chinese parts. Guys were blowing engines left and right trusting Chinese fuel injectors, fuel pumps, water pumps, all sorts of things. It seemed like as soon as you put a Chinese part on, disaster was right around the corner.

I like having nice things and I will always choose quality. It sickens me to see all the low quality stuff coming from China and going straight into the trash (not just car parts)

I totally agree. I blame it on greed and nothing but. All these parts were once made in N America, but companies put profit over quality. What is unfortunate is China absolutely has the ability to produce excellent quality products, but "make it as cheaply as possible" seems to be the mandate.
I would rather pay a little extra once for a good well made product than have to buy the same part twice because it was junk.

 

[351mach1]

So most of the mystery has been solved. It appears my wiring harness was donated from a 72 which is why a lot of the wiring diagrams weren't making sense to me. I am looking at the diagram and can figure it out now...

Answers to questions:
1: This is probably the best option I found for an OEM dizzy: https://performancedistributors.com...-460-1969-1981&attribute_pa_color-choice=blue
2: Still haven't found the correct rotor
3: The ballast resistor is within wire "16" ('72 harness)
4: I should be able to pull 12v from wire 640 going to the C114 connector
5: The 4 pin connector is from a 72 wiring harness with the 4th position being the wire for the A/C compressor. The second 2 prong plug is for emissions equipment which my car does not have

 

[351mach1]

I would rather pay a little extra once for a good well made product than have to buy the same part twice because it was junk.

AMEN!

 

[351mach1]

Alright, I think I've got it mostly squared away. Starts right up! Still need to do some adjusting to get it running smooth but I think the ignition is mostly squared away.

Question: with the vehicle running, should I be reading 12 volts at the ignition coil or 6.5?

Key on without the engine running I get 6.5 from the resistor wire; with the vehicle running, everything reads 12+ volts. I'm worried about burning the ignition coil out.

 

[detritusmaximus]

I totally agree. I blame it on greed and nothing but. All these parts were once made in N America, but companies put profit over quality. What is unfortunate is China absolutely has the ability to produce excellent quality products, but "make it as cheaply as possible" seems to be the mandate.
I would rather pay a little extra once for a good well made product than have to buy the same part twice because it was junk.

That's the problem. China does make good stuff, but the importers are deciding which stuff to bring over based on what the distributors buyers will buy, which is based on which price point is actually moving off their shelves. Not enough demand for the higher quality goods (at a higher price) means they stop producing it.

 

[Don C]

Alright, I think I've got it mostly squared away. Starts right up! Still need to do some adjusting to get it running smooth but I think the ignition is mostly squared away.

Question: with the vehicle running, should I be reading 12 volts at the ignition coil or 6.5?

Key on without the engine running I get 6.5 from the resistor wire; with the vehicle running, everything reads 12+ volts. I'm worried about burning the ignition coil out.

When the engine is running the voltage varies depending on if the points are closed or open, or in the case of an electronic ignition if ground is being applied to the negative coil terminal, or not. Using a regular voltmeter set to read DC volts won't work very well when the engine is running.
Because the voltage reading with engine not running is correct, your primary circuit is good and has the resistor wire in it.

 

[351mach1]

Just what I was looking for, thank you!