# question about bypassing resister wire for HEI distributor



## danthepontiacman (Jul 5, 2008)

ok so on my 66 were does the resister wire tie in? how long is it? and since my car has two wires, the resister wire and the bypass wire for starting why cant i just tie the one for starting in, then splice into the ignition 2 wire right behind the ignition switch befor it turns into a resister wire and run a new wire from that terminal on the ignition switch?


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## Instg8ter (Sep 28, 2010)

same problem, this is what i am doing dan...

Full Power to HEI


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## jetstang (Nov 5, 2008)

G8ter. he is wrong in his diagram, lol.. That is the 87 and 87a, but they are the input wires, a normal headlight relay doesn't have 87a. That is exactly what I was saying, but different. He even talks about installing a diode to correct the run on condition, which is why you installed the relay in the first place. He has 86 and 87 swapped, and you will use the 87a for the starter hot input. I run mine with 10 gauge wire to ensure you get full coil saturation, not 14 gauge.


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## danthepontiacman (Jul 5, 2008)

so why do i even need a relay? i dont think cars in the 70s used theme with the hei? will simply not cutting the resister wire out and makeing it a full 12 volts then connecting it and the crank wire both to the new hei unit?


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## Instg8ter (Sep 28, 2010)

thanks Jet, good catch i had not got into it yet, neighbor had the male harness he uses for Harley ignitions so it will look nice and clean, and i got the switch for 5 bucks.


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## jetstang (Nov 5, 2008)

danthepontiacman said:


> so why do i even need a relay? i dont think cars in the 70s used theme with the hei? will simply not cutting the resister wire out and makeing it a full 12 volts then connecting it and the crank wire both to the new hei unit?


If you just hook them both together, the car will start, but it WON"T TURN OFF, as the wires are backfeeding voltage to the ignition. You need to either install a diode in line, or the relay. Also, you can get a good 12v input to the coil getting voltage directly from the battery. MSDs require a 10 gauge wire to run their boxes. Lack of amps will cause the ignition to break up at higher RPMs.


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## danthepontiacman (Jul 5, 2008)

ok but wont both the resister wire and the crank wire both hook to the same terminal on the relay? since the relay needs to be on in both crank and run positions?


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## jetstang (Nov 5, 2008)

danthepontiacman said:


> ok but wont both the resister wire and the crank wire both hook to the same terminal on the relay? since the relay needs to be on in both crank and run positions?


On a typical fuel pump/headlight relay they would hook to the same terminal, on the relay I'm talking about it has 2 imput terminals, 87 and 87a that both turn the relay on, but don't backfeed each other.


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