HEI distributor
Thread Starter
Cruising
Joined: Nov 2008
Posts: 14
Likes: 0
HEI distributor
Just installed an HEI distributor and replaced the points distributor, do I need to run 12v power to the new distributor and if so what would be the best way?
Any suggestions would be appretiated.
Any suggestions would be appretiated.
Team Owner
Joined: Jul 1999
Posts: 65,492
Likes: 230
From: Orange Park Florida
Yes, you need a 'hard +12' so go inside to the ignition switch itself OR if you can find a PINK wire in the bundle underneath or in the firewall plug on the engine side it turns into a black thin wire that is actually resistance wire....and no good, it leads to the dizzy coil + term.....must jumper that wire either from the terminal on the outside plug, or easier to just drill a small hole in the firewall OR find a place to slip it through and tie into that switch PINK hot wiring.....
don't know how else to quickly explain it....
don't know how else to quickly explain it....
Melting Slicks
Joined: Apr 2001
Posts: 2,030
Likes: 363
From: Lubbock Texas
Make sure you follow the advice given and do this right. Previous owner installed HEI on my '73. He ran a new 12V wire from somewhere in the engine compartment but he also left the resistance wire attached. Whatever he did caused less than optimal voltage to be available to the HEI unit. When I had the car dyno tuned, the shop owner discovered the problem. After running a color correct pink wire of the right size back to the fuse block, he picked up some missing HP.
DC
DC
Le Mans Master
Joined: Sep 2002
Posts: 5,235
Likes: 898
From: Myrtle Beach SC
What did you do about the tachometer? One of the leads from the distributor would route back to the tach.
Thread Starter
Cruising
Joined: Nov 2008
Posts: 14
Likes: 0
Thanks everyone for your input, it was great.
I found the pink wire under the dash and tied into that as you suggested. As far as the tach goes it's a tach drive distributor so it attached the same as the factory distributor.
I found the pink wire under the dash and tied into that as you suggested. As far as the tach goes it's a tach drive distributor so it attached the same as the factory distributor.
Burning Brakes
Joined: Apr 2008
Posts: 945
Likes: 1
Make sure you follow the advice given and do this right. Previous owner installed HEI on my '73. He ran a new 12V wire from somewhere in the engine compartment but he also left the resistance wire attached. Whatever he did caused less than optimal voltage to be available to the HEI unit. When I had the car dyno tuned, the shop owner discovered the problem. After running a color correct pink wire of the right size back to the fuse block, he picked up some missing HP.
DC
DC
The MSD I instructions I have read say nothing about disconnecting any resistance wire. Can someone help me out with a pic or a description of this resistance wire under the hood?
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Melting Slicks
Joined: Feb 2001
Posts: 3,330
Likes: 13
From: Europe , Luxembourg
Hi
The rsistance wire is the original wire on point distributors.
It has unresistet 12 V during starting, but once the ignition switch lets go from starting to engine run position, it runs through a resistor reducing the Voltage to 8 V or so.
The points distributor coils are wired for low V, hence would be damaged if constantly wired to 12 V or even more when engine is running ( up to 14 V )
Only during the starting cycle, when battery Voltage drops down, it is hot wired to have minimum it's 8 V available.
Why they can run a HEI differently, I don't see. Also here the battery Voltage drops down during the starting cycle. So the HEI must be capable to produce enough output from 8 to 14 V . The output Voltage to the plugs must change accordingly !
Rgds. Günther
The rsistance wire is the original wire on point distributors.
It has unresistet 12 V during starting, but once the ignition switch lets go from starting to engine run position, it runs through a resistor reducing the Voltage to 8 V or so.
The points distributor coils are wired for low V, hence would be damaged if constantly wired to 12 V or even more when engine is running ( up to 14 V )
Only during the starting cycle, when battery Voltage drops down, it is hot wired to have minimum it's 8 V available.
Why they can run a HEI differently, I don't see. Also here the battery Voltage drops down during the starting cycle. So the HEI must be capable to produce enough output from 8 to 14 V . The output Voltage to the plugs must change accordingly !
Rgds. Günther
Le Mans Master
Joined: Jun 2008
Posts: 5,284
Likes: 235
From: Rockledge FL
what brand did you get btw.
Instructor
Joined: Aug 2003
Posts: 104
Likes: 0
From: Newfane NY
As stated, point type distributors require battery voltage to start, and were designed to run on reduced voltage to keep the points from 'arcing' .
The points close to charge (saturate) the coil and open to stop the charge and allow the voltage to produce thru to the secondary winding of the coil and produce the high voltage to the spark plugs via the distributor.
A condencer is attached to the points to absorb the voltage while they are open and also prevent arcing. (kind of like a dead end road for the current) When the points close, this turns around and goes back but the points being closed, dosen't burn them.
Regular 'Tune-ups' required the replacement of points and condencers, setting the 'gap' and re-setting the timing,and replacing the spark plugs .
The reduced voltage, via the resistance wire, was the proper ballance to allow all of this to happen 'till they came up with HEI ignition 
Thank you GM!!!
The points close to charge (saturate) the coil and open to stop the charge and allow the voltage to produce thru to the secondary winding of the coil and produce the high voltage to the spark plugs via the distributor.
A condencer is attached to the points to absorb the voltage while they are open and also prevent arcing. (kind of like a dead end road for the current) When the points close, this turns around and goes back but the points being closed, dosen't burn them.
Regular 'Tune-ups' required the replacement of points and condencers, setting the 'gap' and re-setting the timing,and replacing the spark plugs .
The reduced voltage, via the resistance wire, was the proper ballance to allow all of this to happen 'till they came up with HEI ignition Thank you GM!!!
