Need an Ignition Coil?
Thread Starter
Racer
Joined: Sep 2017
Posts: 337
Likes: 56
Need an Ignition Coil?
Hello. I have a sbc 69 with I believe a Pertronix brand ignition added. It runs well but I decided to test the coil. Lots of spare time. The primary #s were approx. 1.8 and the secondary #s were approx. 10.7k. I read one of the older Wilcox articles about testing your coil and it stated any secondary #s below 11k was not good. So I figured the coil was reaching the end. However in reading some post on here it mentions new coils with secondary numbers in the 8k area. Unfortunately the coils for sale has no mention of any primary or secondary specs.
So my question is do I need coil with the secondary numbers that I have? It seems that my numbers are higher than what new ones are, or am I confused over the numbers? If so any preferred brand and oil or epoxy filled. Thank you in advance.
So my question is do I need coil with the secondary numbers that I have? It seems that my numbers are higher than what new ones are, or am I confused over the numbers? If so any preferred brand and oil or epoxy filled. Thank you in advance.
Race Director
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From: Sunshine Coast, Queensland, Australia
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I honestly don't know about Wilcox's instructions for this. I haven't read them. What I do know from being a mechanic for 50 years is this. Coils are a winding. Test specifications given in manuals are generally interpreted as plus or minus 10 percent.
The spec you recite falls in this range. If I were working on it I would call this a pass. Not a fail.
If I was still concerned I would do a spark gap test to check how far this coil can throw a spark. If it can jump a quarter inch gap or more I would not be looking at replacing this coil.
Further more, different brands of coils could well have different specifications as how they are wound may be different.
The spec you recite falls in this range. If I were working on it I would call this a pass. Not a fail.
If I was still concerned I would do a spark gap test to check how far this coil can throw a spark. If it can jump a quarter inch gap or more I would not be looking at replacing this coil.
Further more, different brands of coils could well have different specifications as how they are wound may be different.
Thread Starter
Racer
Joined: Sep 2017
Posts: 337
Likes: 56
Thanks 4-vettes for the quick reply. Found and looked in the Chev. Service Manual and it gives a spec of 3-20k as secondary spec. Huge range. So as you said I'm going to consider that a "pass" and leave things alone.
Race Director
Joined: May 2006
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Not sure where you are looking at new coil specs but MSD publishes their numbers. It's only 4.5k for secondary so you need the actual manufacturers specs to determine whether a coil is good. Since you have no problems nothing wrong with coil.
https://www.summitracing.com/parts/msd-8202#overview
https://www.summitracing.com/parts/msd-8202#overview
Last edited by MelWff; Jun 17, 2023 at 11:20 AM.
Le Mans Master
Joined: May 2007
Posts: 5,025
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From: North tonawanda NY
Also keep in mind Ive read all oil filled coils are made in china these days and replacements are a total crapshoot on quality regardless of branding. I recently had a scare where I thought I needed a coil for the girlfriends 6v bug but the new replacment condensor was just as faulty as the one I tried replacing the first time around.. I am trying to convince her to get the 6v pertronix module that im about to order for my bug as well... im over dealing with points. swapped an HEI in the 74 vette in 2012 and do not regret it.
