Tweet
OK, I know we don't actually drive our cars much at night, but I did so around the block recently for the first time since it has been running again. I noticed a fairly significant change in brightness from idle to driving, as the engine speeds up. Is this simply normal for these years with mechanical voltage regs, or is this a sign of a problem with my regulator?
-
-
Been there...
When your engine drops to idle, the alternator "stalls", that is, it's not turning fast enough to produce 14v. Ordinary passenger cars use itty-bitty pulleys on the alternator to prevent this, but on a performance engine this would be brutal punishment at high engine speeds, prob'ly cause small parts to fly off the alternator or smoke to come out of it, or something. -
Re: Alternator wipe-out
Dave
I hand the incorrect alternator pulley on a 1965 396. When I went through the gears near redline the fan blades on the pulley bent out of shape.
It's common to wipe out alternators at high RPM.Comment
-
Exactly...
Repro large-diameter alt pulleys are available for both Chevys and Fords. Funny thing, they seem to be almost identical. "Form follows function"?Comment
-
Re: Headlight dimming
Tim:
If everything is operating correctly, and you have the proper alternator and regulator, then you shouldn't notice "significant" dimming @ idle. As previously mentioned, the alternator will not supply 14 volts at idle. If your battery is weak, this will cause the lights to dim slightly. Increase your idle speed slightly.
JoeComment
-
Re: Headlight dimming
check the voltage at the headlights vs the battery voltage to see if you have a drop in voltage because of a bad connection or high resistance.Comment
-
PS this should be done with the lights on *NM*
Comment
Comment