I'm in the process of wiring up the engine in my LH & i'm unsure about the power supply to the MSD electronic distributor. The distributor has three wires, an engine earth, a 12+ to the coil & a negative to the coil, i know how to wire these up, what i'm unsure of is will this distibutor need a constant 12V supply like a factory HEI distributor? I know that the factory LH wiring sends 12V on engine crank, then drops to 9V on engine run through an in-built balast resistor wire, will i have to remove or bypass this balast resistor? The instruction booklet i have for the MSD distibutor doesn't have any info & with my limited computer skills i was unable to find anything on this subject on a Google search. Can anyone point me in the right direction? Thanks
MSD DISTRIBUTOR WIRING.
Started by
_LH SLR 3300_
, Jun 29 2011 08:54 PM
13 replies to this topic
#2
_fatlh5000_
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Posted 29 June 2011 - 09:02 PM
I'm in the process of wiring up the engine in my LH & i'm unsure about the power supply to the MSD electronic distributor. The distributor has three wires, an engine earth, a 12+ to the coil & a negative to the coil, i know how to wire these up, what i'm unsure of is will this distibutor need a constant 12V supply like a factory HEI distributor? I know that the factory LH wiring sends 12V on engine crank, then drops to 9V on engine run through an in-built balast resistor wire, will i have to remove or bypass this balast resistor? The instruction booklet i have for the MSD distibutor doesn't have any info & with my limited computer skills i was unable to find anything on this subject on a Google search. Can anyone point me in the right direction? Thanks
Matt,
I did a quick google search for you, and came up with anotehr forum wher this questions has been asked...
http://www.mustangsandmore.com/ubb/Forum12/HTML/011422.html
Hope this is of some help.
Mark
#3
hanra
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Posted 29 June 2011 - 10:43 PM
WIth any Electronic ignition set up you will need to remove/bypass the resistance wire. Its only fitted to limit the current through the points to give them a better life span. You want full 12v supply.
#4
View GaragePosted 30 June 2011 - 03:26 AM
Although the lower voltage idea is intended to extend the life of points in the dizzy, the answer depends on what coil you will be using rather than the dizzy itself. One would presume that you'd put a good quality 12V coil on it as part of the ignition upgrade in which case you'd require a full 12V.
#5
_torbirdie_
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Posted 30 June 2011 - 07:24 AM
Just a little clarification on burning out the points with a 12 V coil.
The fundamental reason for a resistance wire on the coil is that it is bypassed when starting so that the coil receives basically its correct operating voltage when the battery is struggling and drops into the 9V range while cranking the engine.
The coil is designed to have a full output at ~10V, and the points are also constructed with this in mind too.
Two things will happen if the resistor wire is bypassed using a conventional ballast coil, both the coil and the points will have higher currents going through them and either or both may fail.
If you replace the “resistor coil” with a modern 12V high output coil designed for electronic ignitions and give it a 12V feed, most likely it will draw much more current(because it is higher output) and shorter point life will be experienced.
There are 12V coils designed to be used with points ignition(what they had before they started putting in ballast wires etc), they don’t draw more current than the ballast coils, they in fact draw less because they are higher voltage, P = VI.
If they are used in place of a ballast coil then they wont work too well because they aren’t getting the full voltage while the engine is running.
If the ballast wire is bypassed they can be used, but starting the car could be problematic as the coil will be receiving less than the nominal voltage. The points should last just as long or longer than the ballast system.
The fundamental reason for a resistance wire on the coil is that it is bypassed when starting so that the coil receives basically its correct operating voltage when the battery is struggling and drops into the 9V range while cranking the engine.
The coil is designed to have a full output at ~10V, and the points are also constructed with this in mind too.
Two things will happen if the resistor wire is bypassed using a conventional ballast coil, both the coil and the points will have higher currents going through them and either or both may fail.
If you replace the “resistor coil” with a modern 12V high output coil designed for electronic ignitions and give it a 12V feed, most likely it will draw much more current(because it is higher output) and shorter point life will be experienced.
There are 12V coils designed to be used with points ignition(what they had before they started putting in ballast wires etc), they don’t draw more current than the ballast coils, they in fact draw less because they are higher voltage, P = VI.
If they are used in place of a ballast coil then they wont work too well because they aren’t getting the full voltage while the engine is running.
If the ballast wire is bypassed they can be used, but starting the car could be problematic as the coil will be receiving less than the nominal voltage. The points should last just as long or longer than the ballast system.
Edited by torbirdie, 30 June 2011 - 07:26 AM.
#6
_SableMet7/73_
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Posted 30 June 2011 - 12:52 PM
I've got the fitting instructions for a MSD Billet dissy
& the 6A. Can scan them if its any help.
Jono
& the 6A. Can scan them if its any help.
Jono
#7
_SableMet7/73_
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Posted 30 June 2011 - 06:26 PM
I've got the fitting instructions for a MSD Billet dissy
& the 6A. Can scan them if its any help.
Jono
sorry, my mistake
Mines only got 2 wires
#8
_LH SLR 3300_
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Posted 30 June 2011 - 08:00 PM
Thanks for the replies, i'm using a matching MSD Blaster 2 coil & MSD 8.5mm HT leads, at this stage i'm not using an ignition amplifier. What i'm concerned about is if i just connect the original positive coil wire to the MSD coil, the ignition system won't recieve the correct voltage & the car won't run properly. The instructions that came with the distributor are very vague & don't instruct on how to wire it into an existing points ignition system, they focus on setting it up with advance curves etc which was done with the distributor fitted to my engine on an engine dyno. I gather from reading some of the above posts, i need a constant 12V supply to the coil & therefore need to bypass/remove the balast resistor circuit. I don't want to just cut the wire, what is the best way to do this? Obviously when someone converts an existing points ignition to HEI as i've seen done on so many Holden 6cyl Toranas etc they have to modify the wiring & remove/bypass the balast circuit, can anyone show me or point me in the right direction to doing this? Any help is appreciated.
#9
_torbirdie_
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Posted 30 June 2011 - 08:15 PM
Check the torviki:Thanks for the replies, i'm using a matching MSD Blaster 2 coil & MSD 8.5mm HT leads, at this stage i'm not using an ignition amplifier. What i'm concerned about is if i just connect the original positive coil wire to the MSD coil, the ignition system won't recieve the correct voltage & the car won't run properly. The instructions that came with the distributor are very vague & don't instruct on how to wire it into an existing points ignition system, they focus on setting it up with advance curves etc which was done with the distributor fitted to my engine on an engine dyno. I gather from reading some of the above posts, i need a constant 12V supply to the coil & therefore need to bypass/remove the balast resistor circuit. I don't want to just cut the wire, what is the best way to do this? Obviously when someone converts an existing points ignition to HEI as i've seen done on so many Holden 6cyl Toranas etc they have to modify the wiring & remove/bypass the balast circuit, can anyone show me or point me in the right direction to doing this? Any help is appreciated.
http://www.gmh-torana.com.au/forums/topic/29849-torviki-12v-for-elec-ignition/
#10
Posted 30 June 2011 - 08:37 PM
^ That seems like a complicated way of going about it - just bridge the yellow and pink (resistance) wires at the ignition switch. Simple and effective, hidden and can be reversed if needed provided you don't make a mess of it.
With the Blaster 2 coil yes you will want 12V.
With the Blaster 2 coil yes you will want 12V.
#11
_torbirdie_
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Posted 30 June 2011 - 09:03 PM
Couldnt be simpler, connect the pink wire on the fuse panel to the +ve of the coil -how long could that take? 3 minutes?^ That seems like a complicated way of going about it - just bridge the yellow and pink (resistance) wires at the ignition switch. Simple and effective, hidden and can be reversed if needed provided you don't make a mess of it.
With the Blaster 2 coil yes you will want 12V.
doesnt require dropping the steering column to get at the ignition switch or underdash gymnastics.
Also the existing yellow wire is also only rated at 5A, not suitable for the main feed for an electronic ign, not even the bosch hei which uses 7A
Edited by torbirdie, 30 June 2011 - 09:08 PM.
#12
EunUCh
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#13
_Darylle_
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Posted 14 July 2011 - 11:30 PM
I have the msd ready to run with kit with the ss coil, no spark, when I connect the test light to the 3 wires from the dizzy all have power including the black - wire! Is the dizzy stuffed AGAIN? I refuse to go through the crap dealing with the supplier again and I am thinking it's a bin job. What are my options for a reliable HEI system?
Thanks D
Thanks D
#14
EunUCh
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Posted 15 July 2011 - 08:38 AM
Sounds like Hall Sens. type dizzy,if it is from memory the wires are,power,earth and signal,dont know what color wires are what on
dizzy,probly differs from dizy to dizy.
dizzy,probly differs from dizy to dizy.
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