Not sure if this is the right place to post this but I'm curious as to when the AC spark plugs that didn't have the four green rings around them were made? I know some had them and some didn't. I've seen one ebay post showing a set of no green ring AC spark plugs from the 50s. I have these plugs that came out of my '49 Plymouth and I'm trying to find out when they were made. Here is a picture. Thank you! Any info is appreciated.
When were AC spark plugs with no green stripes made?
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ls1mike
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I always thought it was the mid 80's but don't know for sure.
They're resistor plugs; I think resistor plugs showed up sometime during the 1970's.
Here's another forum discussion. It's not definitive regarding timelines. There are some errors in some posts, according to my recollection; i.e. "ACniter" and the "splined" x-section center electrode.
Here's another forum discussion. It's not definitive regarding timelines. There are some errors in some posts, according to my recollection; i.e. "ACniter" and the "splined" x-section center electrode.
Vintage period dated AC spark plugs. - PY Online Forums - Bringing the Pontiac Hobby Together
Vintage period dated AC spark plugs. 64-65 GTO Tempest & LeMans TECH
forums.maxperformanceinc.com
I thought AC became AC delco in the 70s. I'm not sure though.
Thanks. I looked up when resistor spark plugs came out and I was seeing in the 60s so that definitely narrows it down. It's funny I was actually looking at that forum you linked before I made this post. Nothing about not having the 4 green lines but still cool nonetheless.
I believe my brother in law's 70 LS6 Chevelle has the 4 green stripes on them, help him tune up last year, (Don't know why, he never drives it) don't remember if they were resistor or not. His 71 LS5 has resistors in them and I don't believe they are striped. My GS's (67,70 and 72) did not. Maybe its a chevy thing--I don't know, never into chevies. My cars were bought to drive and drag, not to be trailer queens.
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I think the green rings were a recent thing, 1980s-1990s. GM did make their own spark plugs until recently. Now ACDelco plugs are made by Driv(Champion), First Brands(Autolite) or Denso.
Oh really? I was under the impression that AC became AC Delco in the 70s and therefore wouldn't have the "AC" branding anymore on the plug.
There were two versions of the green stripes.
The following is pure conjecture....
From internet images that I've seen of the plugs and their boxes, the two versions seem to follow the timeline when GM merged AC Spark Plug Division with United Delco.
AC Spark Plug Division (? - 1973) = four thin stripes.
AC-Delco merger (1974) = three thin stripes under the thick top stripe.
The GM "cube" appeared on the packaging when the merger occurred.
In 1995 GM dropped the hyphen (ACDelco), the red AC circle and Delco circle. I suspect this is when the stripes disappeared.
en.wikipedia.org
The following is pure conjecture....
From internet images that I've seen of the plugs and their boxes, the two versions seem to follow the timeline when GM merged AC Spark Plug Division with United Delco.
AC Spark Plug Division (? - 1973) = four thin stripes.
AC-Delco merger (1974) = three thin stripes under the thick top stripe.
The GM "cube" appeared on the packaging when the merger occurred.
In 1995 GM dropped the hyphen (ACDelco), the red AC circle and Delco circle. I suspect this is when the stripes disappeared.
ACDelco - Wikipedia
Hmm, ok.....I get what you're saying about the stripes disappearing in the 90s but the AcDelco still remained right? I thought that by only seeing the "AC" on my plugs, they were before AC merged and became AcDelco which had to of been earlier than the 90s or even 80s right? I am just guessing as well ha!There were two versions of the green stripes.
The following is pure conjecture....
From internet images that I've seen of the plugs and their boxes, the two versions seem to follow the timeline when GM merged AC Spark Plug Division with United Delco.
AC Spark Plug Division (? - 1973) = four thin stripes.
AC-Delco merger (1974) = three thin stripes under the thick top stripe.
The GM "cube" appeared on the packaging when the merger occurred.
In 1995 GM dropped the hyphen (ACDelco), the red AC circle and Delco circle. I suspect this is when the stripes disappeared.
ACDelco - Wikipedia
You’re correct when GM united AC Spark Plug and Delco as AC-Delco but until the 1980-1990s GM still treated AC Spark Plug/AC Rochester Division and Delco separately. Delco was the electrical division, along with Packard Wire, and AC was filters, plugs and engine management. ACDelco without the hyphen was a rebranding in the 1990s, along with GM spinning off their parts businesses as Delphi.
I remember as a kid seeing Delco Freedom batteries in Hondas and Toyotas built in Canada or the US(especially Corollas and Tacomas built at NUMMI in Fremont, CA), and a friend of the family installing AC parts on a old Pontiac.
True and also Bosch and NGK - seen them myself.
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