HEI Conversion Wiring Instructions
From Holdenpaedia
Page created by Qute Feb 11th 2006:
[edit] The Relay Method:
The Red Wire in the below diagram is 3.0 mm.
(Image by T Feb 21 2006)
[edit] HEI Relay Holding On After Shutoff:
Submission by T April 1st 2006:
Sometimes an HEI Relay can be affected by Back EMF flowing from the Alternator
back up to the Alternator Indicator Light when the Ignition is turned off. Placing a 6 amp diode in series with the Indicator Wire to the Alternator will cure this.
The current through this wire will be less than 1 amp. I recommend using massively overrated Electronic components in Cars at all times. You will be able to buy a 6 Amp Diode from Dick Smith very cheaply.
Cut the Indicator Wire at a convenient location somewhere under the Bonnet.
Cut the Diode legs until they are about 0.5" long. Using a blue Crimp Connector, crimp the Diode so that the white Band on the Diode is nearest the Alternator.
If there is no white Band on the Diode, then the Diode will be shaped like a bullet. Connect the wire so that the Bullet is travelling towards the Alternator.
The Diode will allow currrent to flow to the Alternator, but no current to flow back.
[edit] Detailed HEI Relay Holding On Explanation by BF6379:
HEI relay hold-onSubmitted by bf6379 on Fri, 31/03/2006 - 23:56.
T,
The wire that you speak of not only provides start up excitation but also controls the alternator warning light (battery light) on the dash. The IND terminal on the alternator that this wire is connected to is fed from an auxillary output of the alternators 3-phase rectifier that primarily provides field current to the armature winding via the internal or external regulator.
When the engine is running and everything is normal the alternator IND terminal supplies +12 volts to one side of the light and the ignition switch supplies +12 volts to the other side of the light. No difference in voltage across the light, no current flows and the light does not glow. If the alternator fails then the voltage at the IND terminal will drop towards zero volts and current will flow through the lamp making it light up.
When you switch the ignition off to stop the engine, the IND terminal continues to supply +12 volts to the light until the engine stops spinning. The other side of the light (which is normally supplied +12 volts from the ignition switch) has a path to ground via the ignition coil and any other accessories connected to the "on with ignition" output of the ignition switch.
This is why the alternator light comes on briefly when the engine is switched off. The current flowing through the coil via the relatively high resistance light bulb is not enough to allow the coil to generate a spark and keep the engine running, the engine stops and the IND terminal of the alternator falls to zero volts.
If the coil is disconnected and a relay wired in its place then the current flowing through the light to the relay will be enough to hold the relay on. Bosch 30 amp relays only require about 20 milliamps to hold the contacts closed. If the relay is on, power is being supplied to the ignition and the engine keeps running, the IND terminal supplies +12 volts to the relay via the light, the relay stays on. Vicious circle.
Applying another load, like handbrake light or reversing lights provides another path to ground and takes some of the current away from the relay, allowing it to turn off.
Brett.
[edit] Diode Not Necessary With This Relay:
I have never had an issue with this modification. when i do it I only use a bosch rely part number 0 332 019 155 .
End of submission by MackV8.
[edit] Implementing the Anti-Hold On Diode Modification:
Submission by T. Dick Smith diode catalogue number Z3229 (10 amps, 1000 volt Peak Inverse Voltage). This diode is overkill but is not likely to blow on you.[edit] The Indicator Wire:
The indicator wire is the thinnest wire that plugs into the Alternator. Usually marked IND.
On 85 Amp Alternators it will be marked I.
To prove you have the right wire, unplug it and turn the ignition on.
You'll notice that the charge light doesn't come on. The charge light
will come back on when you plug it back onto the Alternator or if you connect it to ground.
If you connect the 85 amp S wire to ground you'll see convincing sparks so don't do this.
(Image by T April 7th 2006)
[edit] Anti Hold-On Diode For External Regulator Alternators:
D+ = B+
[edit] Wired Direct to the Ignition Switch Method:
Submitted by knuckles on Fri, 10/02/2006 - 19:00.
It's straight forward to get 12 volts to the HEI coil using the original wiring on a HZ which is the wiring diagram I'm looking at now, but it's the same process/theory,maybe different colour wires on the earlier stuff like EH, HR etc.
On an HZ, working right at the switch block plug socket on top of the steering column under the dash board where the wiring loom comes out of the switch, add a 2.5cm link wire between the PINK & YELLOW wires or strip 1 cm of insulation off the wires & solder the two parrallel wires together (and tape up),the PINK wire is the BALLASTED 10 Volt feed coil wire & the YELLOW wire is the momentary 12 Volt feed coil wire (which is NOT ballasted) & you will have 12 Volts feeding your coil.
Have a look at your wiring diagram specific to your model and you will see what is required and how this will work.
I have used this easy method on my 2 daily drivers and it works just like factory installed HEI, neat, fully functional and 100% reliable.
[edit] Tacho Connection:
The brown Tachometer wire connects to the coil -ve.
[edit] Links:
[edit] Terms:
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