1959 Dodge Coronet - noise from coil??

[WikedPlymouth]

I've just gotten my engine running in my 1959 Dodge Coronet. I had to jump the coil directly from the battery because the resistor was dropping the voltage to 6v and it was not enough to spark the plugs. I've been testing the engine for the last couple of days and now it sounds like a high pitched wine is coming from maybe the coil. Is that possible because I'm running 12v directly too it? I'm planning on getting another resistor but just never heard this before.

 

[halifaxhops]

Can be is it getting hot? Also is it a 12VDC coil?

 

[WikedPlymouth]

It is a 12v coil that requires an external resistor. I did buy a new resistor but it dropped the voltage too low. Will try some other old resistors I have today to see if that's the problem. Just never heard a coil make noise before. Thanks.

 

[halifaxhops]

Look for a .5-.6 ohm ballast. No higher than 1

 

[WikedPlymouth]

Did some more testing. Seems like it's a whistle noise coming out of the 2 barrel carb. Does not happen immediately. Seems that after the car runs for about 15 minutes with the air cleaner off the noise shows up. If I slightly cover the carb opening while it's running with my hand the noise seems to partially go away. Not sure why the carb would start whistling....any ideas? Thanks again.

 

[Gerald Morris]

The idea is to treat the coil as an impedance, then to match the ballast resistance to the impedance of the coil such that when all elements warm to operating temperature, the coil voltage will be high enough to create a good spark, but low enough to prevent the primary side of the coil from premature burn-out. 10 VDC is a good nominal voltage to aim for. The stock impedance for the Prestolite coils used with automatic tranny motors was ~1.8 ohms, which, in series with a .6 ohm ballast made a circuit of about 2.4 ohms. So, the ballast should account for about 1/4 of the ignition circuit voltage, leaving you 9-10V off your coil. I had to twiddle a little using a Taylor coil to find a ballast my motor runs nicely with. Coil impedance is important!

 

[halifaxhops]

Did some more testing. Seems like it's a whistle noise coming out of the 2 barrel carb. Does not happen immediately. Seems that after the car runs for about 15 minutes with the air cleaner off the noise shows up. If I slightly cover the carb opening while it's running with my hand the noise seems to partially go away. Not sure why the carb would start whistling....any ideas? Thanks again.

Lean?

 

[57fury440]

Check for a vacuum leak.

 

[Boydsdodge]

sounds like a shaft vacuum leak on carb

 

[Gerald Morris]

Did some more testing. Seems like it's a whistle noise coming out of the 2 barrel carb. Does not happen immediately. Seems that after the car runs for about 15 minutes with the air cleaner off the noise shows up. If I slightly cover the carb opening while it's running with my hand the noise seems to partially go away. Not sure why the carb would start whistling....any ideas? Thanks again.

Whistling carbs are outside the electrical realm. Have you got any vacuum hoses attached to that carb besides the vacuum advance. Why not plug the vac advance hose, then listen for your leak? Repeat procedure for each and every vacuum line, first on that carb, then, the manifold if you don't find the leak. You can also swap on another 2 bbl carb if you have one handy and in known condition. Start a carb thread about this.

 

[jmustian]

Vacuum leak

 

[WikedPlymouth]

Will check next time I start the car. Just weird that the noise does not happen when the car is first started. The engine needs to idle for at least 15 minutes and fully warm up before it happens. As for the carb, I did rebuild it with a rebuild kit. The throttle shaft seemed solid. There is only one vacuum line running from the carb to the distributor advance. Will try spraying some carb cleaner around the base to see if the idle speed increase to narrow down the issue.

Thanks again for all the help.

 

[Jakter]

I had a vacuum leak on a Stromberg 2brl. carb. Didn't make a noise though.
Couldn't pinpoint it with carb cleaner.
Bought a 2 pack of Swisher Sweets little cigars, put a vacuum hose on the vacuum advance port and blew the smoke in the vacuum line.

Found out my throttle shaft bushings leaked and surprisingly had a leak between one of the three parts.

Sent the throttle shaft part out to be rebushed, put some emery cloth on a thick pane of glass, black marker on the mating surfaces and rubbed the surfaces on the emery cloth lightly until the black was gone.

Everything trued up nicely and the carb is working excellent.