Car runs fine...But starting to "hear" engine rpm thru radio.

[Paul D.]

Have a set of LL plug wires on about 5 year old resto of '67 L79...Car is running good,but I hear tic tic tic thru the FM on the radio. Could these wires be going bad already?.Any thoughts on the replacements as I do not want to do that job again...Could something else be the cause of the noise? I know it is engine related as rpm increases,so does the noise....Thanx P.......ps all the sheilding is on the car

[John W.]

Re: Car runs fine...But starting to "hear" engine rpm thru radio.

Could very well be a diode going bad in your alternator. Usually sounds more like a variable pitch hum that follows RPM with the alternator diodes. You would have to put an oscilloscope on the output of the alternator to verify if that is the issue.