1929 BUICK HEADLAMP BULBS

[raydurr]

Hello guys.1929-41. I am at an end trying to solve my head lamp bulb problem. I have replaced bulbs several times and they still fail after only a few miles of driving. I have used new Chinese looking bulbs and very old new American made bulbs. I have used 32 CP and 21 CP bulbs. Headlamp are completely stock. Wiring is new. Switch restored. No other bulbs of other lights on the car fail prematurely. Charging system is unmolested. Group 1 6 volt battery . All connections are clean and tight. Everything electrical on the car operates as it should. Any suggestions?

[Larry Schramm]

What is the voltage the system is running at and maximum?  If it is over about 7.2 volts, high voltage would be the problem.

[raydurr]

According to my Fluke meter idle voltage is 7.0 and revved I see a occasional max voltage of 7.6. No other bulbs are having issues, only headlamps.

[Larry Schramm]

I would say that you have your generator running on the high side.  The reason that it is just the headlights is that they have bigger wire and good connections.  The other bulbs have smaller wire and poorer connections which will absorb the higher voltage because of the resistance in the wire and connectors.

 

I would look to adjust the output voltage if possible down about .5 volts +- and get the higher RPM voltage in the 7.2-7.3 volt range.

 

I think this would fix your problem.