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Early 70's Ignition Capacitor?

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Old 12-24-2008, 09:44 PM
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RMS73
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Default Early 70's Ignition Capacitor?

In working to eliminate my radio noise I have found a capacitor connected to the positive side of the ignition coil and it is attached to the coil bracket. The AIM, NCRS judging books and other Corvette books I have do not show or mention this capacitor. Does anyones' early 70's have this capacitor? There is a capacity inside the distributor connected to the points and a capacitor on the HVAC blower motor.

Roger
Old 12-24-2008, 09:56 PM
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0Willcox Corvette
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Roger,

There should be a capacitor mounted to the bottom of the coil mounting bracket as shown in UPC U69 Sheet A4 of the assembly manual.

Below is a copy of this page.

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Last edited by Willcox Corvette; 12-24-2008 at 09:58 PM.
Old 12-24-2008, 10:03 PM
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imariver
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My 73 does have a capacitor on the coil bracket.
Old 12-25-2008, 08:30 AM
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My 72 also has such a capacitor, whether mine is doing it's job is another matter though......
Old 12-25-2008, 09:23 AM
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All that cap crap is for AM. Who listens to that anymore?
Old 12-25-2008, 10:30 AM
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Hi Frank,
I Do.
Merry Christmas.
Regards,
Alan
Old 12-25-2008, 12:12 PM
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I found it in the 73 AIM. It is in section B01-B12 sheet 32. The sheet is labeled Capacitors. Other capacitors are shown on sheet 31. The p/n listed is 1852715.

How do you check a capacitor to see if it working?

Roger
Old 12-25-2008, 02:02 PM
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Ok, let's say you actually want to replace the cap, for whatever reason. You go to the local auto parts store, the guy gives you a "one fits all" How do you actually know if it's the right one? We can tell by the numbers on ligit bulbs, sparkplugs, etc. Is there any designation on a cap that you if it's the right or wrong one?
Old 12-25-2008, 02:10 PM
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Hi Roger,
I was curious as to how to test also.
What I found was that you mount the capacitor on a Digi-Bridge LCR Meter and test for storage capacity and leakage profile.
I have no idea what that means!!!
Merry Christmas!
Regards,
Alan

PS: Some electrical savvy person step in please....
Old 12-25-2008, 02:45 PM
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A poster at the NCRS board mentioned using a digibridge RCF meter, whatever it is. I'll check at work next week to see if the electricians have one. Also, there are several capacitors and I want to find out the ratings.

Roger
Old 12-25-2008, 03:15 PM
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Originally Posted by Alan 71
Hi Roger,
I was curious as to how to test also.
What I found was that you mount the capacitor on a Digi-Bridge LCR Meter and test for storage capacity and leakage profile.
I have no idea what that means!!!
Merry Christmas!
Regards,
Alan

PS: Some electrical savvy person step in please....
If you google "rc time constant" you'll get an explaination of how to measure a cap.

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