HEI Module for Breakerless (roughdraft)

[Lord_Athlon]

1975-1981 Non turbo, and 81-85 Turbo cars used a Bosch Breakerless ignition which is solid, but not very elegant.

Components are the
Distributor, Blackbox, wiring harness, and ballast resistor.
The ballast resistor is in the top left of the engine bay under the wiper motor.
The blackbox is usually behind the passenger headlight.
The wiring harness goes under the engine to the blackbox, and on turbo's goes to the blackbox by the battery.

You can simplify the wiring by replacing the box and ballast resistor with the 4 pin HEI module on 70's GM cars.

[84B23F]

You can simplify the wiring by replacing the box and ballast resistor with the 4 pin HEI module on 70's GM cars.

Next year, it will be done...but in the mean time, here is a thread on:

HEI Electronic Ignition Retrofit How-To (http://www.slantsix.org/forum/viewtopic.php?t=15779)


Also, there is a company (http://www.123ignition.nl)that makes distributors for older Volvos; here is their brochure (http://www.123ignition.nl/downloads/folder/123ignition-classic-productsheet-2010.pdf).

PS: This winter, I will review ignition on my 1975 Volvo....if I can find it in one of those green books. I don't understand why a ballast resistor would be used on a non-point distributor.

PS: If you have questions about setting up, ask!
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[84B23F]

You can simplify the wiring by replacing the box and ballast resistor with the 4 pin HEI module on 70's GM cars.

Yes it can be done...but some tidbits that must be heeded:

1. GM's HEI module consumes about 25 amps current when fired up.

HEI systems surge upon first power up, some as much as 25+ amperes. (http://www.chevytalk.org/fusionbb/showtopic.php?tid/188589/)


HEI ignition systems should NEVER be fused. A larger wire gauge really isn't needed to supply the HEI with adequate amperes to operate way past 8,500 rpms, after initial power up. 14 gage is just fine for that, but it is the power up current draw that requires the larger gauge feed wire size.


Consequently, a "10 or 12 gauge wire should be used on this circuit" to 4 pin HEI module.

Which means one will have to use a 35/40 Amp Relay that uses existing Volvo's ignition power-on wire to energize this relay, and a positive wire-10 or 12 gauge-from the battery.

Note - Volvo's diagram shows just one power source that energizes the circuit...sometimes OEMs use two wires...one from start circuit, and one from run circuit. If Volvo only uses one, then only a single wire is needed, and this wire will energize the relay.

Note - Terminal 15 on that box...may be two wires there, btw...only one will have the power from battery circuit. The other wire goes to ballast resistor, and then to coil.

2. Ballast resistor - This was used to reduce output at coil (it just drops the voltage that the coil receives). Some coils come with an internal ballast resistor.

Consequently, the Volvo Coil and Ballast Resistor can still be used...there is nothing wrong with OEM Volvo setup here.

3. 4 Pin HEI Module - It will have to be secured to a heat sink, as shown in that cited article above in previous post.

4. Diagrams - Here below are three different diagrams.

In the first diagram (http://www.jeepforum.com/forum/f8/tfi-hei-hybrid-765919/#post7129782), this person is working with a Jeep. It shows how this circuit would work if a GM equivalent coil is being used. It shows how two different power sources (start & run circuit) are energizing the module and coil.

In the second and third diagrams, scroll down the page 1/2 way and stop at

<big>Wiring diagrams for a Magnetic Pickup Coil</big> (http://gardentractorpullingtips.com/ignition.htm)


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In the first diagram,

GM HEI ignition control module wiring connections for an ignition coil that does NOT require a ballast resistor:

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it shows a simple overview when a ballast resistor is not required.
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In the second diagram, just below the mentioned diagram, he shows ballast resistor in circuit.

Note - I did not read his text, but only looked at his diagrams; they look OK.


Any questions, ask!
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[84B23F]

Footnotes:

1. A a 10 or 12 gauge wire will also have to be used on the ground side, when grounding out the Module. I would use a 10 gauge wire.

2. 2 mm wire is 14 gauge...do not use it as shown in first picture. I would use 10 gauge wire to power up module from relay, and 12 or 14 gauge wires (+ and -) going to coil.

3. When looking at that second set of diagrams-below them, one could use a Chrysler or Ford ignition system also. As the author states, "Crank trigger ignition system will work on virtually any garden tractor with either a single or multiple cylinder engine. It'll also work equally on a two cylinder engine as it does on a single cylinder engine."
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PS: Since there would be a shorter wiring run, 12 gauge wire could be used for all wires involved.
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[84B23F]

Wiring Diagram - I check Volvo Green Manual and found out they use two wires (start & run) to power the circuit. On the 4 cylinder motor:

During start cycle, a full 12 Volts is applied directly to the coil, and this wire is hooked on side of ballast resistor terminal that goes to the coil.

During run cycle, 12 Volts is run to ballast resistor on opposite side of it, which after this voltage passes thru ballast resistor, it then then goes to coil.

So, check your wiring circuits to see if there is any changes from this. Normally, this wiring circuit described above is what a point system uses.

PS: I've never looked at my 1975 244 yet...still trying to figure out how to re-engineer fuel pump system....vehicle has been sitting for past seven years when I bought it...so, I'm going thru fuel system first.