Hi ,first l want to thank everyone who responded to my post"scuffed rear window on C2 softtop" l responded at the end of that post but i,m new at this forum stuf.My question is that l do not have a flasher,ammeter,ignition connector capacitors and the regulator capacitor is there but is not hook up.My engine is a 72 350 cu.in. with a mild cam.Everything works ok.What is the function of all these capacitors and should l be worried.The car came this way. Also as a side bar my carb is a holley 4160 list 9834 date 1897.what year is that.Thanks
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Re: 64 conv. missing some capasitors
Elio,
Does your car have a radio? The function of the capacitors is to reduce (or hopefully eliminate) EMI interference emitting from your car to keep it from affecting other cars. If your car is radio equipped, I would recommend hooking up the capacitors. The Corvette needs them because of the fiberglass body. The steel bodied "passenger" cars don't need them because the body acts as a Faraday cage, containing the EMI.
Joe -
Re: 64 conv. missing some capasitors
If the capacitors are bad they can cause an electrical problem and possibly a fire. Proceed with caution if the capacitor is old. I connected the one to my ameter and it started to smoke.Comment
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Re: 64 conv. missing some capasitors
Bob,
I don't know of any way to test a capacitor with an ammeter. Can you enlighten me on this? I don't mean to be insulting, but an ammeter connected incorrectly (in parallel) can do some damage because it is nearly a dead short between the two leads. The ammeter must be connected in series to measure current flow.
JoeComment
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Re: 64 conv. missing some capasitors
I don't know how to test the capacitors but I'm sure one of the regulars on this site is up on it. I just know that I had one installed on my Ammeter and it was installed correctly and I got smoke from the connection. Fortunatly I caught it quickly and disconnected it before any damage occured.Comment
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Re: 64 conv. missing some capasitors
You can test them (sort of) with a high range analog ohmmeter. First short the lead to the case to discharge it, then connect the meter - at least on the 1 meg ohm scale. The the meter should deflect as the capacitor charges up and then go infinite (in less than a second). That will test it for short, open and leakage. Also, there are some high end digital multimeters that will test them and also display the actual capacitance.
These metal can capacitors used in autos usually do not fail - especially not in a short condition. But it can happen as is evident in Bob's post. Do not try and test them with an current meter.
These caps are available aftermarket, but e-gods - $21
-Dan-Comment
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Re: 64 conv. missing some capasitors
John ,thanks for the insight and yes i do have a radio but i don,t get any static.I,m aware that the date on the carb is 77,87 or 97 but i thought the list no. would be for a more specific year.Thanks to all for the replies and Merry Chirstmass ElioComment
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Re: 64 conv. missing some capasitors
John,
I stand corrected, your explanation makes more sense than the BS I originally wrote.
Does my description cover the noise from unshielded spark plug wires, etc? I suppose that would be heard both in the car radio and in other car radios nearby that are susceptible to that sort of interference.
JoeComment
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Re: 64 conv. missing some capasitors
Close...but not quite right...
RF (radio interference) can be radiated and/or conducted. In the case of radiated noise, the Corvette's lack of a metal body to act as a Gaussian shield IS a problem. That's one of the reasons ALL Corvettes had the radio antenna located at the REAR of the car (get it as far from the engine compartment as possible).
But, when the noise components are conducted, they travel the electrical system's power supply branches and provide interference that way. The body construction of the vehicle (conductive vs. non-conductive) is a total non-issue when it comes to conducted vs. radiated RF noise.
You'll find passenger cars with metal body construction DID use RFI capacitors on various electrical components known to generate 'trash' frequencies by the very nature of their operation (e.g. electromechanical voltage regulator, heater-A/C blower fan, ignition coil, Etc.).
So, the above statement is kinda/sorta true but NOT universally true...Comment
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Re: 64 conv. missing some capasitors
Jack,
You mentioned on another thread that often you think you're talking to yourself. Well, being an EE myself, I'm always interested in what you have to say. I have not studied automotive electrical systems in great detail yet, but would definitely like to learn more.
I think I know what you mean here, but would like to clarify:
"But, when the noise components are conducted, they travel the electrical system's power supply branches and provide interference that way. The body construction of the vehicle (conductive vs. non-conductive) is a total non-issue when it comes to conducted vs. radiated RF noise."
You mean that the body construction is a non-issue when it comes to conducted noise, right?
This thread has me wondering why they didn't eliminate some or all of these capacitors by simply filtering the 12 Vdc inside the radio? I work in avionics, I see filtered 28 Vdc power supplies quite often.
Also, just for grins, how many of these capacitors does a 64 have and what are they connected to? I assume that's in the AIM, but I don't have one for a 64.
JoeLast edited by Joe R.; December 16, 2010, 09:20 AM.Comment
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Re: 64 conv. missing some capasitors
Bob,
I reread the thread, I completely missed what you were saying the first time around! I thought you were talking about connecting an ammeter in parallel with a decoupling capacitor in a live circuit. That's a very bad idea! But you were talking about the capacitor installed on the car's ammeter. Sorry, my bad!
JoeComment
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