Spark Plug Wire colors?

[Graham Man]

I was hoping someone might be able to enlighten me on spark plug wire colors and dates/years used. 

Most of my cars are 1930 era, my question is what color wires used, year wise approximately?  7mm or 8mm?

 

Yellow with Black & Red tracer solid core? Years?

 

Red with Yellow & Black tracers solid core? Years?

 

Black solid core? Years?

 

I always like color under the hood, but original is more important...I am guessing all replacement wires were normally black.

 

Thank you for the help!

 

[Spinneyhill]

It is my belief that most cars would have had black plug leads when new. Still cloth braided and lacquered.

[Curti]

Since you specialize in Grahams there must be some factory documentation.  I did the research on 1934 -1936 Auburns and have determined they were gloss black.  

[Graham Man]

Maybe I am just overthinking this, could these old designs wires just be the Accel spark plug wires of their day, and never came on cars originally?

 

[Graham Man]

Curti,

    There is not much Graham-Paige documentation remaining.  Factory pictures are the best source.  I have not seen any documentation that would suggest anything other than black rubber from Graham-Paige.   If the aftermarket wires were available in red and yellow I am still curious on the years they were available.

[Curti]

The yellow wires were, they used them on 810-812 Coirds

[Graham Man]

So 1936 and 1937 Cords used Yellow with red and black tracers. 

 

I have some photographic evidence that looks like Graham-Paige used yellow with the red and black in 1928 and 1929 on the eights, 835, 827 & 837 cars. (period pictures, from auto shows, but auto shows were rarely real life)

 

 

[Curti]

A disclaimer: I am not a Cord historian.  This is hear-say on my part.  My expertise lies in 34-36 Auburns and I am dabbling in 31's & 32's . I have spent the last 20+ years documenting these cars. We have original very low mile cars that are an excellent representations of how the factory actually built them.  My hobby is  restoring the cars exactly the way the factory built them, no better no worse.  I HATE  bling. I am sure there are guys in the Graham club that have the same passion.

[PFitz]

48 minutes ago, Graham Man said:

So 1936 and 1937 Cords used Yellow with red and black tracers. 

 

I have some photographic evidence that looks like Graham-Paige used yellow with the red and black in 1928 and 1929 on the eights, 835, 827 & 837 cars. (period pictures, from auto shows, but auto shows were rarely real life)

 

If the pictures are close to when the car was new, then that's some of the best evidence of what was on the car when it left the factory.

 

Sometimes documents didn't match what was on the car because changes made during a production run weren't always updated on the documents.  Especially as factories fell on hard times and made cutbacks in staff.

 

Paul

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Edited October 27, 2017 by PFitz (see edit history)

[Rusty_OToole]

The woven cotton covering was to protect the rubber insulation. When they used natural rubber it was prone to drying out and cracking, or getting soaked with oil and gas. It lasted longer if protected. The rubber insulation with woven covering was used up until the early fifties then was replaced with vinyl around 1955. They went to bare spark plug wires much earlier. They must have had some kind of synthetic rubber that was too expensive for all the wiring but was used on plug wires. When this started I don't know but the difference should be obvious in old photos of new engines.

[Graham Man]

OK apparently I am still getting up to speed...So all spark plug wire is cloth covered till the 50's. So the trick is to figure out what color the manufacturer used. So I started digging literally. What I found was one last coil lead on my almost completely original 1929 Graham-Paige 827 30,000 miles.   The coil wire looks like orange with a black tracer, now to find a good supplier.

 

 

Edited October 29, 2017 by Graham Man (see edit history)

[PFitz]

Most likely, it was not originally orange colored. A lot of the older wire was what is called 'oak" color - darker than yellow. And the clear lacquer coating made it even darker as it aged.

 

Rhode Island Wire has lacquered, 7 mm, solid core oak with black tracer. Plus the terminal ends you'll need. And the crimp-on ends should be soldered to the core for reliability.   

 

http://www.riwire.com/

 

And they also have Graham wiring harnesses.

 

They also carry sizes of that black, braided wire loom in your picture that was used in some harness and sometimes used as a stone-guard covering for exposed lengths of the copper/nickel brake lines..

 

Paul

Edited October 29, 2017 by PFitz (see edit history)

[Graham Man]

You guys are awesome!  Looks like a perfect match.  

 

I am assuming 7mm was the norm, vs 8mm?

[PFitz]

7mm most likely. It was a very common size then.

 

Paul

[Rusty_OToole]

No! the CAR wiring was cloth covered until about 1955. Spark plug wires lost the cloth covering in the 30s. I guess they had some kind of synthetic insulation that did not need the protection that they used only for plug wires.

Edited October 30, 2017 by Rusty_OToole (see edit history)

[Graham Man]

Rusty,

    From my Graham-Paige research you are correct, so far I have only been able to confirm the cloth covered for Graham-Paige through 1929.  If you look closely at the original black and white pictures you can see the boots and plug wires are a different color till 1930.  I am still trying to figure out what year Graham-Paige made the switch to black synthetic.  It makes sense once the engineering improvement was proven most companies would have switched over to the synthetic spark plug wires.

[John_Mereness]

On 10/27/2017 at 11:50 AM, Curti said:

The yellow wires were, they used them on 810-812 Coirds

When I bought my 1935 Auburn sedan it had a spare cap in trunk and on it was a set of leads in black with a few maroon leads (dark maroon shiny cloth braided wire) mixed in (and since have accumulated a couple other maroon leads)  - my guess is that the Cord had maroon leads and the maroon leads came on the Auburns from having the car serviced at someplace use to working on Auburns and Cords. Attached is a picture of a Cord - do not know color of wires, but they certainly DO NOT look black.

[John_Mereness]

13 hours ago, Graham Man said:

You guys are awesome!  Looks like a perfect match.  

 

I am assuming 7mm was the norm, vs 8mm?

Nice look 

[Spinneyhill]

1 hour ago, John_Mereness said:

Attached is a picture of a Cord - do not know color of wires, but they certainly DO NOT look black.

 

Nice photo.

Can you help me out here please John. I can't see any plug leads - I am not familiar with these cars.

[Graham Man]

Just ordered 50 ft from Brillman 7mm Cotton Braided Spark Plug Wire 0.99 per foot, Color and tracer spacing looked close 7mm

 

Thanks again

 

Available in multiple colors. Specify desired color below. Enter length as “Qty”, below. #B9917-xxx, 7mm Cotton Braid Spark Plug Wire (Has Copper Conductor & PVC Insulation with 1 Layer of Cotton Braid & Lacquer, Manufactured In The USA By The Brillman Company. (Sold By The Foot)

 

 

[Rusty_OToole]

I don't know when the change occurred. Looked at a documentary on the Ford V8 for information, it showed contemporary pictures of the brand new 32 engine, it has black plug wires. Yet we are informed that Cord was still using cloth covered plug wires in 1936 or 37. So who knows when different makes changed over, or why.

[Graham Man]

I would think it was an engineering call.  If the lacquer coating cracked it would let in moisture causing arcing and misfires.  I agree you would think early 1930s.  I have two 1933 Graham Cars both with original black wires (non-cloth covered) (I think, both cars under 30,000 miles documented).  If we could figure out who introduced the new synthetic coated wires we might be able to get a patent date.

[PFitz]

The braided and lacquered covering on all those fabric covered wires were not the insulator, I that was to protect the rubber insulation under it.

 

According to the folks at Rhode Island Wire, who've been making  period-correct replacement wiring, copied from originals, for over 25 years, there was no set time period when auto manufactures switched from fabric covered to more modern coverings. They said that some companies stayed with fabric covered up to the 1950's, including spark plug wiring.

 

I remember you could still buy new-off-the-roll fabric covered spark plug wiring in some autoparts stores into the late 1960's.

 

Paul

Edited October 31, 2017 by PFitz (see edit history)

[Dave39MD]

This looks close to what your car originally had. The wire color is consistent down into the roll but may have darken with age like yours.

 

Dave

[Graham Man]

Dave,

   That is amazing you have the original packaging!  I always save the original packaging on NOS parts they just look cool.  I have been searching for the patent for the black synthetic coating.  I will enter this information and see if I can find it. 

[John_Mereness]

On 10/30/2017 at 2:35 PM, Spinneyhill said:

 

Nice photo.

Can you help me out here please John. I can't see any plug leads - I am not familiar with these cars.

The wires partially run in conduit - you can see them just below the rubber hose on the radiator - going from distributor cap into the conduit.

[jan arnett (2)]

Here is my 1923 Moon which I just finshed restoring  with  NOS wires.