HEI dizzy wiring help

[Talkwrench]

Hi guys need a little help with wiring [my favourite ] Installing a HEI dizzy and would like to find the best 12 volt ignition source and how to tidy up the wiring after removing the ignition box, ballast, etc. I thought it may have been one of the blue wires going to the ballast resistor but they seem to only have just over 10 volts with ignition on ..

[Chryco Psycho]

you will need to hook it to both the blue run wire & the brown start wire at the ballast resistor . do you have clean connections at the bulkhead & steering column ? you should have 13.2 v minimum at the ballast
 the rest can be deleted

[Talkwrench]

I take that the two wires together will come up with the 12 + volts, I will check the connections too. I assume that the connections at the firewall have other wiring in with the ignition wiring , I simply cant pull  that block out and make new wiring from there, so it can be tidy? When you say at the ballast resistor you dont mean keeping it?

[Chryco Psycho]

no ballast needed with an HEI
the engine will not start without connecting both the brown & blue wires to the HEI , brown is voltage while cranking blue is run , you should have more than 12v on either wire you are losing power somewhere so if the battery is not low there is resistance somewhere in the circuit .

[Talkwrench]

OK understood, Im sure I checked the brown wire and got nothing?? Cant be right  Anwyay I'll have a crack at it later when home and see how it goes.
Thanks for the help

[Chryco Psycho]

brown wire is only powered when the key is in the start position so it takes two people to test it , one to hold the key in start position , one to check for power

[Talkwrench]

OK understood, makes sense. I have bridged the wires blue and brown together that is at the ballast to by pass it and tested the brown tail wire that goes to the coil, with the ign "on"[ not run] Iam only getting 10.5 volts ,at the battery 12.25 volts. Should I be getting the full 12.25 at this point?

[Cuda54]

If you can not get full voltage use a 12V relay to get full voltage for the HEI.

[Talkwrench]

Thanks thats what Im thinking at this point 

[Chryco Psycho]

yes you should have the 12+ v at the blue wire , you could use a relay to get full voltage to the HEI

[Strawdawg]

I doubt you will get the voltage that you are looking for as there is a lot of voltage drop between the battery and the brown/blue wire under the dash.  By the time you go thru the bulkhead connector to the switch and back thru the bulkhead, you have ample opportunity for loss.  I rewired my car with a direct feed thru the firewall to the switch as the the ammeter had burned up and melted a bunch of wires in a prior life so I went alternator to battery and a feed thru the firewall bypassing the bulkhead connector.  I did not change the feed thru the bulkhead on the way back out, however..and still had a volt drop under the hood.

I then used the brown and blue tied together to trigger a relay which fed power straight  from the alt/battery to the module and resolved that issue.

On my to do list is to check the voltage under the dash on the blue and brown feeds to see if the drop is in the switch, or in the bulkhead.  I am going to do this because the alternator is getting a voltage from the blue wire as a reference and it is one volt lower than the battery is seeing which tells the alternator to charger harder than it really needs too.  Electrics, you gotta love 'em

[Talkwrench]

I have wired direct to the battery for power because everywhere else had less than 12 volts, this of course through a relay setup. Today I am picking up a new Bosch coil [HEC716] and also a Bosch module [BIM024] the module alone is going to cost me more than the dissy !!
I have purchased one of those cheap Chinese copies of a Bosch HEI dizzy, I have to say Im quite impressed with how it looks, its kind of hard to fualt.. quality ,well that could be in the electrics.
I am replacing the module for the "real deal Bosch" because after talking with an electrical engineer [DTec] He said that he has tested many of these modules over the years and of course the Chinese stuff was all over the place.
So as it stands.
$69. for the dissy to my door
$65. HEC716 coil
$90. module
$21. Relay and wiring.
= $245
Im hoping that the curve in the dissy is as they stated, Should be a nice ignition when finished.
 I am upset as when I sold my last car I had one of those coils and spare modules as spares in the car and had been meaning to get it out from behind the seat .. damn forgot!!

[Talkwrench]

Fitting the HEI was easy enough however the "stated" specs where way off, total timing wasnt coming in till 4000RPM ! they claimed 2800 which would have been nice, so I had the "guts" the thing and change the timing and curve. Its not bad at the moment Its all in by 3000 -3200 rpm , initial 11.5 degrees, but I think I will get it down to 2500 - 2800 and have a higher initial timing say 16 degrees.. Ahhh more fun.
I must say that it runs very nice, starts well, picks up and goes, well worth the change! and thats with the vacuum advance [hahaha]. Plugs set at 1.3mm [.052].
 But now shes undercharging  before was overcharging...oohh MoPar electrics  I'm hoping its a simple as they way I have bunched the wiring up..?

[Strawdawg]

so does the voltage come up with rpm, or is always low?

[Talkwrench]

Yesterday while testing the dissy again started out ok but there is a full 1volt drop by the time it gets to the battery !
On the weekend when I took the car for a run, seemed to be about 13.75 at the start and then  look down at the guage voltage dropped away to 12 volts 
The regulator is new and I had replced the reg because of a high reading, nothing changed seemed high again and now this 

In short no it doesn't change that much with revs