Author Topic: Need advice on Distributor/Ignition Setup  (Read 2240 times)

Offline Total BS

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Need advice on Distributor/Ignition Setup
« on: March 05, 2006 - 08:35:13 AM »
Hi gang, 

When I bought my 71 Cuda 383 Auto with A/C it had an aftermarket Accel distributor and box in it.  Now it is in the process of an extensive rotisserie restoration and I would like to get a distributor that would be considered correct for my setup.  The only problem is that I am mechanically clueless as to what I need to get. Mopar performance sells a bunch of different setups but I am not sure which is right for me. Can anyone shed some light on this for me? I currently have the chrome electronic ignition controller on the firewall.  Here is the setup I was looking at from Summit Racing.  Please tell me what you think.  Would I also need a coil or does the electronic ignition eliminate that.  Like I said...technically inadept, so please help.
THanks, Ed
1971 'Cuda 383
1970 Chevelle SS LS6
1999 Durango
-New Joisey-




Offline FY1 RT SE

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Re: Need advice on Distributor/Ignition Setup
« Reply #1 on: March 05, 2006 - 09:37:11 AM »
The "correct" distributor would be a points distributor.   Yes, you need a coil with an electronic ignition.

« Last Edit: March 05, 2006 - 01:54:16 PM by FY1 RT SE »

Offline Chryco Psycho

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Re: Need advice on Distributor/Ignition Setup
« Reply #2 on: March 05, 2006 - 01:31:41 PM »
the kit you show is what I would use but the Chrome box is a better box , & if you have a chrome box you must already have a electronic dist so really buying the kit is pointless , I would buy a high output coil , Pertronics has one that looks absolutly stock & the MSD Blaster can be used if painted black   
 as mentioned above the correct dist would be a points  type

Challenger - You`ll wish You Hadn`t

Offline FY1 RT SE

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Re: Need advice on Distributor/Ignition Setup
« Reply #3 on: March 05, 2006 - 02:01:05 PM »
So it's time to replace the coil. That one at the auto parts store is sure to do the trick. Because it's yellow and it has a shiny sticker that says it's a supermegavoltfireballthunderspark coil and like most performance parts, it will make you go faster, if only because it lightens your wallet by so much.

Okay, Okay - Let's talk voltage first, since this is the main entrance for most people's trip down the garden path.

Q: How much voltage do you need? A: Enough for a hot spark. Q: How much is that? A: .........uh, isn't more better?

Now that some of you have been insulted, let's try to put some real numbers to the problem. Suppose you have a motor with 9:1 compression and an air/fuel mixture of 14.7:1. It's a nice cool day and your driving down the coast about 25 feet above sea level. You've just installed a new cap and rotor, a fresh set of spark plugs gapped at .035", and a new set of plug wires. For good measure, you just changed the oil and washed the car, so it's really running sweet.

So how much voltage do you need?

Oh, about 12,000 volts (12Kv).

What about when you nail it to pass the Good Sam going 35 in the 65 zone? Okay, maybe 14Kv.

But that monster coil you just installed is still putting out 60,000 volts to the plugs just like it says in the magazine ad, right? Nope, sorry. See, once the voltage has built up high enough to jump the plug gap, its job is basically done. After the plug fires, the voltage required to sustain the arc is much lower than the firing voltage. At this point, what's important is to shove as much current across the gap as possible.

When you get home you discover your annual smog check is due today. So you run out and turn the mixture screws to lean out the motor. Firing voltage just went up to 14Kv. But the motor won't run right because there are fewer fuel molecules to interact with the spark. So you open up the plug gaps to .045". Firing voltage just went up again, maybe to 16 or 17Kv.

So just how do you get 60,000 volts (or even half that) to the plugs? You don't, except maybe in the lab. You see, high voltage is a strange beast. It tends to crawl over things or go through things you'd expect would stop it. If you kept opening the plug gaps, you'd find it increasingly difficult to get the voltage to the plug. At about 25KV, it would much rather run down the outside of the plug though the oil and dirt left from your fingerprints when you screwed it in or arcing through the tower of you new coil.

Does this mean 60,000 volts is complete fiction? Well, that depends on your view of reality. If you string together two car batteries in series (24 volts) and fire the coil a few times with no load attached, and it makes 60Kv just before it dies, is that coil not in fact capable of producing 60,000 volts?

One thing you will never see on a coil box or ad is "This coil is capable of producing up to 30,000 volts when measured in accordance with SAE specification XYZ " Even more enlightening would be a graph of how the coil voltage falls off with rpm. Of course this would be death in the marketplace. Can you imagine the shiny yellow coil promising nothing short of the ability to arc weld, next to the one that says "well, I start out at 30,000 volts and go down from there - buy me". Which would you choose?

So by now the question in your mind might be "If it takes so little voltage to fire the plugs, why do I need even a 30Kv coil?" Three important terms to keep in mind: Secondary Available Voltage, Required Firing Voltage, and Reserve Voltage. Secondary Available Voltage is what the secondary side (or high voltage side) of the coil is capable of producing - say 30Kv. Required Firing Voltage is what it actually takes to jump the plug gap - perhaps 14Kv. Reserve Voltage is the difference between the Available and Required voltage - 16Kv (i.e., what's left over).

So what good is this reserve voltage? Well, as the spark plugs begin to wear and loose the sharp edges on the electrodes, the required firing voltage may go up by 1 or 2Kv. Likewise for the cap and rotor. Inspected your plug wires lately? Burned or broken conductors, usually by the crimp area will still function, but may require an addition 3 to 4Kv to overcome the additional gap.

Therefore, one could assert that the primary benefit of a high voltage coil is to increase the service interval of the ignition components, keeping the vehicle in tune longer. This statement will no doubt bring howls from the turbonitrousblowninjected crowd, but that's not really the focus here. Most people's experience is with passenger cars (ouch! It still hurts from when someone called my high school ride that - a nice '69 Dart with fat tires, loud exhaust, and really cool stripes), that are unlikely to be substantially affected by a performance coil.

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Re: Need advice on Distributor/Ignition Setup
« Reply #4 on: March 05, 2006 - 02:36:52 PM »
Great explanation FY1 RT SE!   :thumbsup:   Appreciate your effort, thanks for taking the time to explain it fully...    :cooldancing:   ...Oldschool

Offline MEK-Dangerfield

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Re: Need advice on Distributor/Ignition Setup
« Reply #5 on: March 05, 2006 - 02:55:19 PM »
FY1 RT SE,

  I just have to add this. My car was troublesome to start cold when I first got it. By that, I mean below 40 degrees outside. I put in an ignition system by FBO. It fires right up now, no trouble. Just for kicks, I repalced the FBO ignition box, with the Chrysler orange box. It started, but after many turns. Then I put the FBO ignition box back in, and installed the stock Chrysler coil. I got the same deal. It started, but only after many turns. So my conclusion is that there MUST be something in the FBO ignition box/coil combination that makes my car happy. Somehow, I am getting more juice to the goose with it.  :bananasmi  I don't understand it, and I'm in the electronics field by trade.  :banghead:

  Mike

Mike

1970 Challenger - SOLD
2016 SXT+.  1 of 524 SXT+'s in Plumb-crazy for 2016.

Offline Total BS

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Re: Need advice on Distributor/Ignition Setup
« Reply #6 on: March 05, 2006 - 07:21:26 PM »
Wow,  Thanks for all the info.  You guys are an amazing knowledge bank.

The distributor that was in the car was accidentally trashed so I will be buying a new one just to be safe. Is black cap or tan cap correct?

Chryco, I checked out the Pertronix coils.  They have 40,000 and 45,000 units.  Any one better that the other and how do these compare to the Mopar Performance coils.   Below are three of the items I was looking at.  Comments appreciated.

Ed
« Last Edit: March 05, 2006 - 07:35:35 PM by Total BS »
1971 'Cuda 383
1970 Chevelle SS LS6
1999 Durango
-New Joisey-

Offline FY1Challenger

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Re: Need advice on Distributor/Ignition Setup
« Reply #7 on: March 05, 2006 - 07:50:37 PM »
Hi gang, 

Now it is in the process of an extensive rotisserie restoration

If you are going through all that work why would you not put an as correct coil as possible on the car?


Offline Total BS

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Re: Need advice on Distributor/Ignition Setup
« Reply #8 on: March 05, 2006 - 10:10:45 PM »
FY1,

Here are two I found on Ebay. Big difference in price. I have a lot more parts to buy so I would lean towards the new OEM one for now until my finances recover a little or should I bite the bullet and go NOS. I would assume the OEM one is the same as you showed in your picture with the green lettering.
Thanks again for your opinions...
1971 'Cuda 383
1970 Chevelle SS LS6
1999 Durango
-New Joisey-

Offline Chryco Psycho

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Re: Need advice on Distributor/Ignition Setup
« Reply #9 on: March 05, 2006 - 11:30:39 PM »
go with a 35 $ coil , the pertornics with the decal removed looks stock too

Challenger - You`ll wish You Hadn`t

Offline FY1 RT SE

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Re: Need advice on Distributor/Ignition Setup
« Reply #10 on: March 06, 2006 - 01:02:47 AM »
The "NOS" coil shown is a '74 and up coil (Interesting he doesn't tell the date code in the auction).  OEM correct coils are available for about half that price and are made with the original molds that Chrysler used when they made them.  They also come in a wide selection of date codes.

Offline FY1 RT SE

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Re: Need advice on Distributor/Ignition Setup
« Reply #11 on: March 06, 2006 - 10:34:15 AM »
FY1 RT SE,

  I just have to add this. My car was troublesome to start cold when I first got it. By that, I mean below 40 degrees outside. I put in an ignition system by FBO. It fires right up now, no trouble. Just for kicks, I repalced the FBO ignition box, with the Chrysler orange box. It started, but after many turns. Then I put the FBO ignition box back in, and installed the stock Chrysler coil. I got the same deal. It started, but only after many turns. So my conclusion is that there MUST be something in the FBO ignition box/coil combination that makes my car happy. Somehow, I am getting more juice to the goose with it.  :bananasmi  I don't understand it, and I'm in the electronics field by trade.  :banghead:

  Mike

Several things could cause the problem you described.  Wire length and configuration are just a few of them.  Chrysler ECU's were made in 5 different configurations and if the ECU wiring is not made to accept ALL the different types then the energizer bypass circuitry will not operate correctly.  For example the original ECU boxes are different than the current MP box which is different that the Autozone or Pep Boys box.  In addition, an extended wire length run/spiced wires to "hide" the box or place it in an area other that were the factory would have installed it may hinder both the voltage and current required to operate the box.

Offline MEK-Dangerfield

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Re: Need advice on Distributor/Ignition Setup
« Reply #12 on: March 06, 2006 - 03:05:59 PM »
Several things could cause the problem you described.  Wire length and configuration are just a few of them.  Chrysler ECU's were made in 5 different configurations and if the ECU wiring is not made to accept ALL the different types then the energizer bypass circuitry will not operate correctly.  For example the original ECU boxes are different than the current MP box which is different that the Autozone or Pep Boys box.  In addition, an extended wire length run/spiced wires to "hide" the box or place it in an area other that were the factory would have installed it may hinder both the voltage and current required to operate the box.

Hmm,  :screwy:

  I think you have hit on something there. Being a 70, my car came with points style ignition, that got swapped out for electronic somewhere down the line. The box is not mounted on the firewall however. Someone saw fit to mount it on the passenger's side inner fender. I'm not keen on where it is, so this gives me an excuse to try an relocate it. Thanks for the input.  :thumbsup:

  Mike

Mike

1970 Challenger - SOLD
2016 SXT+.  1 of 524 SXT+'s in Plumb-crazy for 2016.

Offline 74MOPAR

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Re: Need advice on Distributor/Ignition Setup
« Reply #13 on: March 12, 2006 - 11:09:59 AM »
 I have the FBO system on my 'Cuda as well, and I'd recommend it also.
Not only does it start easier, I would swear the engine runs smoother. at 60 mph I can tell the difference compared to the chrysler pieces. {my car is a 74 so it had electronic ignition form the factory]
« Last Edit: March 12, 2006 - 11:11:41 AM by 74MOPAR »
74 'Cuda + 73 Charger Rally + $$ + assembly= Noble M400
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