72 Ignition System
Printed From: The Ford Torino Page
Category: Model Specific Forum
Forum Name: 1972-1976 Ford and Mercury
Forum Description: Technical discussion for 1972-1976 Ford and Mercury
URL: https://forum.grantorinosport.org/forum_posts.asp?TID=17050
Printed Date: 23-April-2024 at 7:37PM
Software Version: Web Wiz Forums 12.06 - https://www.webwizforums.com
Topic: 72 Ignition System
Posted By: lynchster
Subject: 72 Ignition System
Date Posted: 27-April-2018 at 7:54PM
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I'm looking to pick a brain or two for some ignition info relative to my car. At the moment I have the car (72 / 351C / Rally gauges) up and running using the old dual point distributor. I figured it was the easiest way to get it fired for now. I'm upgrading it to electronic ignition but I'm going with a relatively stock look. So far......... The engine is at 10.3 - 10.4 compression I bought a recurved duraspark distributor, it's set up for full advance at 2800. I also plan on using the small distributor cap and 8mm wires. The questions start from there. Do I have to alter how the factory tach is wired depending on the set up? Should I start out one range colder on the plugs? Duraspark I, Duraspark II, or just go for a MSD 6AL and try to inconspicuously mount it where the voltage regulator sits. (I might go with a different alternator). Anything I should look into or be concerned about? Thanks ------------- Chuck 72 Gran Torino Sport 13 Taurus SHO "Mr Pig" |
Replies:
Posted By: aquartlow
Date Posted: 27-April-2018 at 11:18PM
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You should not have to change the connection to the (-) side of the coil, whichever coil you chose, for the factory tach to work correctly. The Duraspark I or II distributor is a good choice, uses same type of magnetic pick-up that an MSD distributor uses(copied), The DS ignition system will return good spark energy and are usually very reliable, the biggest issue with the DS ignitions are the somewhat troublesome replacement modules now available. There are aftermarket manufacturers that make better modules but can get pricey and wait time if a replacement is needed is something to think about. A slightly colder plug is a good idea, I like NGK's due to their quality, reliability and lower resistance #'s(potentially more spark energy at the gap) as compared to Champion or Autolite plugs. MSD ignitions aren't as reliable as they once were(at least that is what I have heard/been told) but you can usually get parts at local auto parts store(O'Reilly's). The bigger distributor cap was developed for a reason, the increase in spark energy would cause crossfiring issues in the smaller caps due to the plug wire terminals being too close within the cap, not sure if you would have an issue but just a heads-up. ------------- www.supermotors.net/22468 Yeah, It's a Hybrid...It burns gas and tires. No matter how good she looks, somebody, somewhere, is tired of her sh*t. Beauty is skin deep, ugliness goes clear to the bone. |
Posted By: 72FordGTS
Date Posted: 28-April-2018 at 7:16AM
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For the ignition system, pretty much any upgrade over stock requires 12 volts without a resistor wire. Since the tach runs in series with the coil, this becomes a problem. What I did is have mine converted by rocketman to be a voltage sensing tach. That way you can run whatever you want without having to worry about frying the tach. Plus if the tach fails, it doesn't leave you stranded. I am running TMI's Duraspark distributor with a built in GM HEI module. It pretty much appears as a stock Duraspark, but has no real external wiring. And GM modules are dirt cheap, easy to find, and IMO better than the Duraspark modules. I was lucky enough to get the prototype distributor and I don't kow if they have gone into regular production. That said, you can do what Todd did. He runs a Duraspark with an GM HEI module mounted externally. There is a bit more wiring involved, but it's still very straight forward. With this setup you have a an all Ford distributor and a GM HEI module, both of which are cheap and easy to replace at any parts store. Try that with all MSD parts. Check out this old thread I started, it has a ton of info in it on different ignitions. Plus it has the details on Todd's setup. http://forum.grantorinosport.org/msd-6al-points-trigger-oem-tach-duraspark-hei_topic16025.html?KW=dura+spark+hei" rel="nofollow - http://forum.grantorinosport.org/msd-6al-points-trigger-oem-tach-duraspark-hei_topic16025.html?KW=dura+spark+hei ------------- Vince 1972 Ford GTS Sportsroof - Survivor, One Family car GTS.org Admin |
Posted By: Rockatansky
Date Posted: 28-April-2018 at 11:32AM
if that's true they're really in trouble! i remember when they first came out the stock cars& whatever other form of racing they'd have a panel within reach of the driver with the spark box & maybe the coil mounted on it ... and a back-up that the driver could swap over the pigtail plug-ins if the car went dead on the track then there's the acronym Most Suddenly Die  IDK about the large diameter cap thing, i'm suspicious that it was just engineering over-kill but there were some 80k-100k + volt systems. the standard DS coils should be OK with a small cap IMO i like the GM module mod, isn't there a 5 pin module that includes the retard on start function? Rockauto has the DS1 module & coil for reasonable $ but i think the 2 wire tach would need to be converted ------------- 72 GT Ute |
aquartlow wrote:Posted By: lynchster
Date Posted: 28-April-2018 at 2:30PM
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You guys are an encyclopedia of knowledge. ------------- Chuck 72 Gran Torino Sport 13 Taurus SHO "Mr Pig" |
Posted By: aquartlow
Date Posted: 29-April-2018 at 12:47AM
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IIRC, the start retard function can be found on DS II ignition modules(Blue strain relief-when white wire has + voltage applied) but I have not done any tests to confirm this with the factory DS II system. I currently use the GM 5 pin module that has start retard function when a ground signal is placed on the 5th pin. This module can found on '80 Oldsmobile Toronado with 307 engine(Standard LX330), but using a true GM module is your best bet(I use GM#1976239 or a D1941 can be substituted). While testing ignition components before installation I found BIG differences in resistance in distributor cap(coil terminal to rotor button), coils, plug wires(of course) but even in different brands of spark plugs(I use resistor-type plugs to keep radio static free). Every elevation that is made in resistance will lessen the spark energy and/or duration at the spark plug and having more spark energy is the main reason I changed my ignition system. Another option you get for using a GM module is that it has variable dwell as rpm's rise/fall whereas the DS II systems do not, not a deal breaker but just another plus. You can see by the chart below the DS I system was from '77-'79 and utilized a system without an ignition resistance wire(12v signal while at crank AND 12v signal while running is sent to ignition coil) which made the ignition basically "hotter" or high output. This type of system is what I accomplished with using the GM module/TFI coil(no resistance wire, low resistance coil) due to not either being able to find RED strain relief DS I module or have faith in it's lifespan.
https://www.google.com/url?sa=i&rct=j&q=&esrc=s&source=images&cd=&cad=rja&uact=8&ved=2ahUKEwiCp8ubtd_aAhURxVkKHbkaAPEQjRx6BAgBEAU&url=https%3A%2F%2Fwww.ford-trucks.com%2Fforums%2F1429262-duraspark-i-purgatory-cranks-but-does-not-fire-weigh-in-on-my-troubleshooting-3.html&psig=AOvVaw0TX19OFRq-sGlGAvc7To8m&ust=1525088945790718" rel="nofollow">
 ------------- www.supermotors.net/22468 Yeah, It's a Hybrid...It burns gas and tires. No matter how good she looks, somebody, somewhere, is tired of her sh*t. Beauty is skin deep, ugliness goes clear to the bone. |
Posted By: Rockatansky
Date Posted: 29-April-2018 at 11:46AM
oops i referenced DS1 as having retard on start but Yes i'm pretty sure now that George Pence often laments that the Red strain relief DS1 module does not include that function... fixed it  the ultimate trick would be to use the factory Duraspark wiring harness and a Red strain relief module case with a 5 pin GM module fitted inside  ------------- 72 GT Ute |