Dear Forum,


as the old regulator on my 1966 442 started to go beyond 16V, I ordered a AC Delco D663 from RockAuto to replace it.


Replacing is no witchcraft, just removing the 4-wire connector block, unbolt the regulator, re-bolt the new one and connect back (yes, battery was disconnected during that). Grounding to firewall is perfect, cleaned everything before bolting on.


Firing up the engine with light on and GEN lights up. Let it run for "1.2 minutes" (thats exactly stated in the manual), then increase RPM until GEN goes out, let it run a while like this and back to idle, where GEN shall go out.
Everything was fine, happy customer !


Next day: starting the 442, GEN stays on in idle and voltage regulator produces a very loud buzzing with GEN on. Stepping on gas and buzzing plus GEN is gone. Voltage (I have a Voltmeter installed) is around 14V in idle and 15V with higher RPM.


Switching on lights or fan/heater drops voltage to 12-13V.


I decide to test-drive and after some minutes the GEN only lights up at around 1500RRM and the buzzing appears.


Now regardless of additional consumers.


I put the old regulator back in and everything (except the high voltage) is fine...


What causes that buzzing at certain RPM ???


Thank you for any Suggestion, Alex.

 

Sounds like a defective VR.

 

Update: swapped the ACDelco for a cheap Wells VR715 (hint from Camaro forum) and everything works.
Wish you all a nice Sunday.

 

Glad you got it fixed.