6v Ignition wire to coil replacement

[Phil Gillespie]

My 39 Coupe continues to test/try my patience.
Has rebuild 3rd Generation Distributor, rewould Skip Coil and a new 33mf condenser 3rd Generation. This engine will still give a miss/hesitation once its up at operating temperature.
Fitted with new Stromberg 97 carb. Filter in line. Blew back through fuel lien to fuel tank. running 180 thermostats.


Original ignition switch I took apart and cleaned up all contacts.
I will run a new wire from ignition switch to resistor to coil.
What gauge wire is recommended for this. Over the years some wiring has been replaced and want to solve this ongoing problem.
I had my resistor mounted at coil but will now relocate on firewall when rewiring to coil.
Appreciate advice given.
Phil NZ

[Terry,OH]

#14 AWG is good. You may want to look at the terminations at the two ends of the wire. Have you looked at the Spark Plug wires and their terminations? Don't use the resistor type plug wires. Have you put a vacuum gauge on the engine?

[Charlie ny]

Phil,
Help me out here, what is a third generation distributor ?
Charlie ny

[Frank Miller]

Originally Posted by Charlie ny

Phil,
Help me out here, what is a third generation distributor ?
Charlie ny

Michael Driskel 3rd Gen Automotive I assume.

[flatheadmurre]

Does it miss sitting idling or at higher rpm...unloaded/lodaded.
Checking condensor seems like first step...even new ones come with a dodgy way of going open when hot nowdays...
Installing an A/F meter while driving will tell you what´s going on...if fuel related.
If both above comes out fine...something opening up letting exhaust pass..gasket/crack may be next suspect.
An intake valve sticking gives funny symptoms..

[Charlie ny]

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If Mike did the distributor I'm sure it is correct in every regard. My suggestion here is a royal pita but if you have not already checked the inner caps for continuity you might consider doing that ASAP. It is my feeling that a simple continuity light is the only way to be sure the inner terminals to the wire sockets is above reproach and has true continuity is if the the light is bright when checking from the terminal to the socket. Forget the ohm meter.

Anyhow I've had very similar conditions and found the the culprit to be
the inner caps and poor continuity. The spark will actually jump the gap between
the inner terminal and the wire socket not good.........I've chased my 'tail' on situations like this.........good luck.
Charlie ny

[Phil Gillespie]

Originally Posted by flatheadmurre

Does it miss sitting idling or at higher rpm...unloaded/lodaded.
Checking condensor seems like first step...even new ones come with a dodgy way of going open when hot nowdays...
Installing an A/F meter while driving will tell you what´s going on...if fuel related.
If both above comes out fine...something opening up letting exhaust pass..gasket/crack may be next suspect.
An intake valve sticking gives funny symptoms..

This engine was put on a dyno and A/Fwas checked and correxted with 46 jets, running a single carb. So blew back from fuel pump yp tank to check.
Have a vaccum gauge fitted and vaccum is good at 20 inch idle and around 14 to 15 at cruise.
Thats why I'm now going down new coil wire path from ignition.
Plug wires show a good blue spark jump at idle. Copper core cloth outter covered. These could break down at load? causing miss?
Phil NZ

[Phil Gillespie]

Originally Posted by Frank Miller

Michael Driskel 3rd Gen Automotive I assume.

Yep thats what I meant along with the new condenser.
Phil NZ

[Phil Gillespie]

Just been to pick up my generator and regulator from Auto Electrician for service check.
Also picked up cable and connections for coil rewire.
He indicated that if spark plug wires are solid wire, as opposed to carbon type then highly unlikely to have a fault there. Mine are the solid copper wire type.
Phil NZ

[JSeery]

What do the plugs look like?

[flatheadmurre]

Coppercore wires don´t break but they may have insulation issues...check for arcover between wires and engine.
Seen new wires look like fireworks when you turn off the light in the garage.
Arcover in distributor caps.
Think you done everything right so hard to point at something obvious.
Modern condensors are high on the list...if it was run on a dyno the heat was way lower then whe installed in the car.

[Tinker]

you don't want carbon wires less its electric ignition. copper on points is right. try a ih200 napa condenser.


not related; You can only run effectively solid core on old magneto hit/miss engines.



ordered wires from these guys. bulk wires and colors. If i remember right about 12-14 ft covers all the plugs on a v8 with a ft extra,

https://www.thehotrodcompany.com/

sparkwires modern coating. page 2 ford non electronic ignitions.

https://www.thehotrodcompany.com/pro...ark-plug-wire/


if you look around the site, they supply all sets of sizes of wires in bulk in tradition cloth look. (16g)



.

[Phil Gillespie]

So an update on the above :
Today fitted a NOS Ignition switch, old one had been cleaned up but was grooved.
Wired resistor just under dash and have ensured all wire from ignition switch to resistor, from resistor to coil is in good order. Spark plug wires are copper core so after checking all intact and good continuity.


I have now done 2 small trips 30 mls round trip and all is good.
Generator regulator was checked and is opersting well 6.37v after run back home.
All connections checked on coil wire.
Some readings bearing in mind small changes as resistor heats up.
Points are closed.
Battery Voltage: 6.37V. Ignition switch voltage: 6.37V. Resistor cold: 2.5 ohms.
Voltage to resistor: 6.15v. Voltage after resistor: 2.9v. Voltage at Coil: 2.5v.
Amps to resistor Not running: 4.5A. Amps to resistor Running: 3.09A
Amps resistor to coil Not running: 2.57A. Amps resistor to coil Running: 3.09A.
Running Amps did drop from 3.09A tp 2.75A.
At coil at idle: 3.02A 3.3V.
The above readings I'm pretty happy with and will continue to drive and observe.
Presently starts up very well smooth idle. Was it fuel related or electrical, as i did blow back through to fuel tank. fuel pump pressure is approx 2psi.
Driving will tell.
The spark plugs are a nice tan colour nil oiling, apprear good.
Have Edebrock heads, running spark plugs are NGK V/Power 25671A-7. A plug which has electrode non protruding past thread. Termed a non-projected spark plug.
Phil NZ

[Tinker]

Sounds like things are progressing.

[Phil Gillespie]

Originally Posted by Tinker

Sounds like things are progressing.

Wanted to get some logic and concrete fault finding to end up with reliable parts. Instead of just swaping out items, crossing fingers and hoping for the best.
Phil NZ

[dumb person]

Originally Posted by Tinker

you don't want carbon wires less its electric ignition. copper on points is right. try a ih200 napa condenser.


not related; You can only run effectively solid core on old magneto hit/miss engines.

.

May i ask why that solid copper core is bad on road engines? I've been using it a while now and wonder if i should change it for multi-strand.

[tubman]

I'm a Packard 440 person on all of my old cars. There is nothing to listen to on AM radio in my neck of the woods, anyway.

[Tinker]

https://www.hotrod.com/articles/1006rc-ignition-wiring/


From link:
First off, your particular ignition system will tell you what type of plug wire you should or-more importantly-shouldn’t use. Early points-style ignitions and magnetos used low-resistance wires to carry a lower voltage as compared to modern systems, which can easily carry up to twice the load, thus requiring a higher tolerance wire. Running a modern, spiral-core suppression wire with the early ignition can actually decrease the voltage being carried to the plugs; running the early solid-cores with a high-output (breakerless, capacitive discharge, or HEI) system can easily result in damaged electronic components for the exact opposite reason. There’s more to a plug wire than the color of its skin.


Magneto is used on hit/miss engines.

[JSeery]

Originally Posted by dumb person

May i ask why that solid copper core is bad on road engines? I've been using it a while now and wonder if i should change it for multi-strand.

Not totally sure I understand your question, but some electronic ignitions don't play well with solid copper wiring. I believe solid core and multi-strand is the same thing when referring to plug wires.

[koates]

Checking the voltage setting of your voltage regulator with engine running at approx. 2000 RPM the reading at the armature or battery terminal on the regulator should be 7.3 to 7.5 volts. Generator at engine idle speed will not be charging the battery. Regards, Kevin.