409 ignition \ wiring help needed

64 Hard Top · Addicted!

409 ignition \ wiring help needed

4SPEED427 · A Poncho Legend!

If that resistor is for the coil, I would be guessing that the car already has a built in resistor wire to the positive side of the coil. The purpose is to drop the voltage to about 9 volts (I think?) for when the car is running. The coil only gets fed 12 volts during cranking. If you test the voltage at the coil and it's about 9, you should be good to go.

With that said, I am NO guru on the earlier (or any!) B bodies but that is what I've been told as far as system operation.

64 Hard Top · Addicted!

So in other words ,... with a standard 9 volt coil ,.. I don't need a resistor? Does it make for starting problems without the resistor\12 volt configuration?

4SPEED427 · A Poncho Legend!

No, you use a normal 12 volt coil. It should say on it "for use with external resistor" or something like that. Then you test the wire that goes to the positive side of the coil to make sure it has about 9 volts when running, 12 volts when cranking. If so, it should all be good because the coil has no idea if it is sitting on a 283 or a 409.

Is the 283 still in the car and running?

4SPEED427 · A Poncho Legend!

The way it works is the positive side has 2 wires to it. One should be 9 volts when tested with the key on. The other one should be about 12 volts when tested ONLY when cranking. At any other time the "other" wire should be dead.

The Big Kahuna · Addicted!

Funny to see this post tonight, as I was also working on wiring for my '64 Parisienne and noticed the same thing.

I was looking at a '64 409 tonight, and it had an external resistor on the firewall. When I checked the '64 283 car, it has no external resistor.

looks like this external resistor is a 409 specific item. This is good to know if you are trying to make your car a 409 clone.

4SPEED427 · A Poncho Legend!

I never knew about this before I read this thread, but I've never followed 409's either (not that I don't wish I had a 409 car.....)

I wonder why the resistor done that way instead of a resistor wire like all the others.

I may peek in some service manuals to see if they may have an answer.

64 Hard Top · Addicted!

I looked in the service manual tonight and it indicates that ignition coil resistance is ""in wiring harness"" for all engines including the 283,327 and 409 with hydraulic cam (340HP). It lists a "ballast resistor" for the other two 409 engines with mechnical cam.

The two high preformace 409s have 1.03-1.13 primary ohms and 7500-10,500 secondary ohms.

The 283,327 and 409 with hydraulic cam (340 HP) all have 1.28-1.42 primary ohms and 7200-9500 secondary ohms. (ballast equipped)

Automotice electrical was never my strong point

Does this make sense? It appears that the two higher horse power 409 engines with mechanical cam need different primary and secondary ohms

??

Yes,.. the 283 is still in the car and running at the present time. I thought I needed to reerarch this ballast resistor issue before proceeding.

-- Edited by 64 Hard Top on Tuesday 3rd of August 2010 12:22:33 AM

4SPEED427 · A Poncho Legend!

I can only guess maybe they are trying to improve the spark on the higher performance 409?

Given how primitive the whole ignition system is on our 60's cars that almost seems a bit humourous that they even attempted that if it is truly the case.

64 Hard Top · Addicted!

These are the two photos from a factory 1964 409 car (taken by a CP member) posted elsewhere. It doesn't appear to have a ballast resistor on the firewall. So I guess it must be the 340 HP version. ??

The 64 409 which you looked at tonight which had the ballast resistor,.. was it a factory 400 or 409 HP car? Or was it a clone.

I'm not really concerned about "clone looks". I'm more worring about flaming wiring harness.

The Big Kahuna wrote:

Funny to see this post tonight, as I was also working on wiring for my '64 Parisienne and noticed the same thing.

I was looking at a '64 409 tonight, and it had an external resistor on the firewall. When I checked the '64 283 car, it has no external resistor.

looks like this external resistor is a 409 specific item. This is good to know if you are trying to make your car a 409 clone.

-- Edited by 64 Hard Top on Tuesday 3rd of August 2010 12:40:30 AM

64 Hard Top · Addicted!

Carl Stevenson wrote:

No, you use a normal 12 volt coil. It should say on it "for use with external resistor" or something like that. Then you test the wire that goes to the positive side of the coil to make sure it has about 9 volts when running, 12 volts when cranking. If so, it should all be good because the coil has no idea if it is sitting on a 283 or a 409.

Is the 283 still in the car and running?

Thanks carl.
Yes,.. that makes perfect sense. The coil is matched with an external resistor ,... which is a "wire type" resistor ,..so called "in harness resistor".

Only thing that remains is curiosity ,...as to why the 400 and 409 HP versions needed a ceramic ballast resistor. ?? It was the same single point distributor on all 3 HP versions of the 409 in 1964. It would seem to me that GM might have been attempting some sort of "heavy duty use" with the ceramic version. But,. realistically,.. and practically,.. I've yet to hear any reason as to why a ceramic ballast resistor was used when a "in harness wire resistor" matched with the proper coil would do the same thing.

Anyone out there with a guess ,...
??

-- Edited by 64 Hard Top on Tuesday 3rd of August 2010 12:40:18 PM

Pontiacanada · A Poncho Legend!

Hey Randy,

I'm just glad to see that you're dropping your 409 into your '64!
It should be a very fun car!

... Darryl.

65wagon · Poncho Master!

dont sweat it, if you have acess to a 283 6cyl car trace that funny white wire with the fabric insulation unplug it from the harness and transfer it will work 409s ran a higher voltage no bigy today

OURWAGON · Guru

WHY NOT JUST BY A ENGINE HARNESS AND RESISTOR FOR A 64 CHEVY 409.
IF GOING INTO A PONTIAC , SHOULD BE NO PROBLEM.

65wagon · Poncho Master!

you could also just pick up a new resistor, i thought this was a quick fix if its not a 409 car wire a regular wire in get a proper resistor and done no need to change everthing unless you really want too

pontiax · Poncho Master!

being that iam an electrician, i'll throw my 2 cents in.
contact points were invented when 6 volt systems were the norm. when 12 volt systems were used, a resistance wire was used to drop the voltage to 6 volts because points will burn up with any thing more than 6 volts. standard coil draws about 9.5 amps. hp coil draws 11.75 to allow for higher secondary voltage. resistance wire will not handle the higher amperage. so a higher value resister is used with regular wire.

64 Hard Top · Addicted!

Thanks for all the suggestions. I'll take the coil from the 283 that's in the car and connect it the same way when the 409 is installed. Carl is right ,.... the ignition system doesn't know if it's a 6 cylincer, 283 or 409. So if I connect it the same way to the existing wiring harness and coil,.. I think I should be ok.

Curiosity still makes me wonder though ,.,...
,......why did some 409 equipped cars have a ceramic ballast resistor. ??

-- Edited by 64 Hard Top on Friday 6th of August 2010 04:51:38 PM

65wagon · Poncho Master!

the manuel lists the voltage output between 5to 7 volts high pos are 7 volts or up you can get away with a higher voltage for awhile but shorten point life

danhunt · Newbie

'63,'64,and'65 chevy 409 cars all had a ballast resistor.340 hp cars had a low pef resistor,400 and 425 had a high perf resistor.I can't see pontiac being different
These parts and most other 409 parts can be bought from Show Cars on ebay.

mr409 · Addicted!

I tried this with my 61 Parisienne rag years ago. I tried using a USED 61 Chevy harness and it was SLIGHTLY different. I think there was 1 more or 1 less wire in the circuit-maybe due to Pontiacs having an Ammeter?? Yes you're right about that underhood shot of a 64 Pontiac 409 being a 340 horse.

65wagon · Poncho Master!

just snip of that wire to the ampmeter its a fire waiting to happen. those things are live all the time convert over to a voltage gage