I pulled the HEI out of my 66 because I am putting it back to points. I want to run the factory tach with no worries and I've never had issues with point ignition anyway.
The question is, I found the resistor wire to the coil was pulled apart at the bulkhead connector. I made the connection just to test, but it has a full 12 volts at the coil
I know I can just put in a ballast resistor but why isn't that wire dropping it to about 9 volts like it should? If I hook up the coil this way, I know what will happen, I'll be burning up points, coils, whatever....
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1966 Strato Chief 2 door, 427 4 speed, 45,000 original miles
1966 Grande Parisienne, 396 1 of 23 factory air cars
I'd love to hear the answer to this too. I have found many times this same problem, especially when the connector is broken off and i crimp a new one one.
I know that the length of the wire is important i think? but i would not think that an inch or less would make a difference.
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Beaumontguru
MY BEAUMONT HAS 4 STUDDED TIRES AND 2 BLOCKHEATERS......AND LOTS OF OIL UNDERNEATH. The other one has a longer roof.
That's the thing, the wire is intact except the last inch at the bulkhead. The wire inside the firewall that connects to it never was a special resistance wire was it? It was just normal, and the voltage drop was all done with the wire in the harness on the outside of the firewall if I'm right. I would love to be corrected but anything I can find in manuals says that is how it is.
I don't want to install one of those Dodge resistor blocks but that is a better option than having 12 volts to the coil all the time.
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1966 Strato Chief 2 door, 427 4 speed, 45,000 original miles
1966 Grande Parisienne, 396 1 of 23 factory air cars
I know that the length of the wire is important i think?
Yes it is, but when I was doing a quick search a while ago, I found it is hard to find an exact answer to this kind of info. My '64 has no ballast resistor from the factory ... the wire (type/gauge/length) provides the resistance. My wire is not copper in nature.
Someone did a "buckshee" connection on mine a long time ago, and I wanted to look into fixing it. My car starts every time, so, so far I have the "if it ain't broke, don't fix it" attitude, but I'd like to get the proper info. and clean it up in the future.
'64 409 cars used a ballast.
Did they use a ballast on smaller block cars in '66?
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Prince Edward Island
'64 Parisienne CS "barn find" - last on the road in '86 ... Owner Protection Plan booklet, original paint, original near-mint aqua interior, original aqua GM floor mats, original 283, factory posi, and original rust.
I'm trying to remember my electrical theory from 30 years ago. The resistor wire feeding the coil is only a couple ohms, and I wasn't aware it dropped the voltage at the coil to 9v, I thought it would stay at around 12v. However, the current would be limited. Putting the key into the start position sends the full current to the starter solenoid, which then sends the full 12v to the coil on the yellow or white wire.
I'm trying to remember my electrical theory from 30 years ago. The resistor wire feeding the coil is only a couple ohms, and I wasn't aware it dropped the voltage at the coil to 9v, I thought it would stay at around 12v. However, the current would be limited. Putting the key into the start position sends the full current to the starter solenoid, which then sends the full 12v to the coil on the yellow or white wire.
Yes, but I tried it with the key only in "on". There's no point in having the wire from the starter for cranking if the so-called resistor wire has 12 volts in it anyway.
Darryl, I've never seen a ballast on a 66 Chev or Canadian Pontiac yet. At least not a factory installed one.
The head scratching continues....
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1966 Strato Chief 2 door, 427 4 speed, 45,000 original miles
1966 Grande Parisienne, 396 1 of 23 factory air cars
Just looking at my original 64 cs 409 engine pics and I do not see or remember a ballast resistor on the firewall. When I converted my present 64 to a MSD HEI I replaced the resistor wire from the firewall block with a new wire to run a full 12v to the HEI. The wire replaced is the resistor. The 12v for starting comes through the ignition switch in start position that runs to the starter solenoid. When the car starts the ignition goes to run and the resistor wire comes into play for 9v to the points. So an HEI just needs one 12v wire and the solenoid wire is not needed. You will need to install a wire from the solenoid if you plan to go back to points. Brian
hey Carl you know my opinion about points, i love to run them reliable but,i actually spent the money on a new distributor its a petronix flame trower, it uses our window caps and is easilly tunable which is my reason for running it, i can tune it transfer the specs to my points and its done, its also compatiable with our tachs and it can run both 12 or 9 volts, otherwise run a full twelve volts to a ballast droping it to nine.
yes Amps X ohms = the amount of volt drop. If and open circuit is zero amps and zero times any ohms is zero so no volt drop. The only way to test a resistor wire is with current flowing through it under a load. It needs to be grounded by the points in order to draw any amps. My stock 69 has a 1.35 ohms resistor wire a stock coil draws 1.8 amps under idle so 1.35 x 1.8 = 2.43 volt drop 2.43 from 12 volts is 9.57 volts. In the start mode the coil draws around 4 amps so 4 x 1.35 is 5.4 volt drop. 5.4 from 12 volts is 6.6 volts and that why you need the 12 volt additional wire in the start mode from the starter to the coil to get it started.
-- Edited by Beaumont4008 on Saturday 9th of February 2013 11:03:47 PM
'64 Parisienne CS "barn find" - last on the road in '86 ... Owner Protection Plan booklet, original paint, original near-mint aqua interior, original aqua GM floor mats, original 283, factory posi, and original rust.
I think you still have an open circuit. Try closing the points and then testing. The points need to be closed before a voltage drop will show.
Now this makes some sense. As I said above, I was trying to remember my electrical theory. If you've got an open at the coil end, then yes you will read 12v. Closing the points will ground the other side of the coil, and I presume then load the circuit, and hopefully provide the desired result.
Just looking at my original 64 cs 409 engine pics and I do not see or remember a ballast resistor on the firewall. When I converted my present 64 to a MSD HEI I replaced the resistor wire from the firewall block with a new wire to run a full 12v to the HEI. The wire replaced is the resistor. The 12v for starting comes through the ignition switch in start position that runs to the starter solenoid. When the car starts the ignition goes to run and the resistor wire comes into play for 9v to the points. So an HEI just needs one 12v wire and the solenoid wire is not needed. You will need to install a wire from the solenoid if you plan to go back to points. Brian
All the original wiring is still in place. The previous owner simply added an HEI and ran a new wire from the fusebox for a full 12 volts. I am just deleting that wire and going back to the points ignition with the regular coil wired in to the stock harness. I just wanted to test the resistor wire to make sure of the correct voltage because the connection for that wire at the bulkhead was bad. I suspect that is the reason he put an HEI in the car in the first place.
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1966 Strato Chief 2 door, 427 4 speed, 45,000 original miles
1966 Grande Parisienne, 396 1 of 23 factory air cars
I have seen some rear defogger wire harnesses that use what appears to be the same wire. That's how they make low and high speed on some of them. Others use a resistor right on the defogger switch.
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1966 Strato Chief 2 door, 427 4 speed, 45,000 original miles
1966 Grande Parisienne, 396 1 of 23 factory air cars
I have seen some rear defogger wire harnesses that use what appears to be the same wire. That's how they make low and high speed on some of them. Others use a resistor right on the defogger switch.
I used the resistive wire from a defogger when I made an engine harness when I did the 454 transplant into the convertible.
Found this when I was looking into the Crane XR-i point conversion yesterday. Looks like grounding the negative post on the coil will do the same thing as closing the points. Not sure why they say 8 volts instead of 9 though.
Quick Test for Ballast Resistance
You can determine if your vehicle has external ballast resistance with this simple test. Disconnect any wires going to COIL-(negative terminal). Reconnect battery. Turn the ignition key on but do not start the engine. Use a voltmeter as shown in Figure 2 and read voltage between COIL+ terminal and ground. It should be about 12 volts. Then momentarily jumper the COIL-(negative terminal) to ground. If voltage at COIL+ terminal drops below 8 volts, there is ballast resistance between the ignition key and COIL+ terminal. To determine if your coil has internal ballast resistance, use an ohm meter as shown in Figure 1. Coils with internal resistance will read 3 to 4 ohms. from coil negative and positive posts.
-- Edited by Beaumont4008 on Wednesday 13th of February 2013 02:10:54 PM
I haven't been working on the car too much. I started stringing the plug wires late last night. Those front two on each side are fun, running through the motor mount etc. All the original retainers have been removed so I'm scrounging parts to get them installed. I am hoping maybe to run it next week.
I am wondering how I can test that wire to make sure the drop is there as it should be. I think as Ian suggested the only way is to hook it all up and then open and close the points.
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1966 Strato Chief 2 door, 427 4 speed, 45,000 original miles
1966 Grande Parisienne, 396 1 of 23 factory air cars
It's going to have to be running to draw enough load to pull the voltage down... Manually opening and closing the points will only create a draw until the coil is charged which is very quick.
If it is the correct wire it will be fine ie. if 20" of wire drops the voltage down to 9.... 18" of wire will drop the voltage down to 9.2 - 9.3?? You would be hard pressed to measure the difference in point life.
Who's to say it was ever really 9 volts anyway as it depends on load and input voltage.... (rpm, coil draw, temp etc. etc. etc)
If the wire was spliced I would be more concerned by the connection... that stuff is a bear to solder! Gary
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72 Nova SS - Minitubbed 70 Nova SS - #'s L-78 Bench Stick 68 Acadian SS clone - factory air 67 Chevelle rag - SS 427 clone
just call M&H and order a new one, you can buy just the correct resistor wire with the correct terminals and lugs..then you know its right, they probably put the HEI in it because it wasnt running right, the resistor wires age and fail...
you need the resistor wire or it will weld your points closed...i can look at my 4 speed car and see how long it is..its untouched
