rocketraider Posted May 12, 2004 Share Posted May 12, 2004 1964 GP- installed a repro Delco DC12 battery today, everything looked fine. Drove car about 30 miles in 85 degree temps, got back, battery was vigorously boiling acid out the vent caps. Stopped as soon as engine was shut off. Checked voltage at battery terminals w/ engine running (and battery boiling) 14-16v depending on engine speed and electrical load as per shop book specs.Finally replaced 4 yr old Echlin regulator (that had been working fine with modern Delco maintenance free battery, and no stuck or burned points) with an NOS Delco part. Voltage at battery was still 14-16, but battery quit boiling with the new VR.I don't know enough about external VRs and vent-cap style batteries to determine why the battery boiled with the Echlin part. I remember people used to have to add water all the time because of this condition, esp in hot weather. Adjusting a VR has always struck me as a black art. Can anyone offer a simple explanation? Or tell us why the Echlin part did this? Link to comment Share on other sites More sharing options...
decembro Posted May 12, 2004 Share Posted May 12, 2004 First thought that comes to mind is maybe you have a bad ground on the voltage regulator. Just for grins, hook a jumper wire from the mounting screw of the regulator to the negative post of the battery and recheck the voltage. 15.5 volts is the absolute maximum for something of this vintage. Another possibility is that your battery is fried now from having boiled and the new regulator won't help it because it's too late. Have the battery tested. Might be sulfated. You really want 13.8 to 14.8 volts. 14.2 is ideal. Find out what amperage you're getting out of the generator too. Might be the generator is frying your regulator.Steve Link to comment Share on other sites More sharing options...
Mrbuick714 Posted May 17, 2004 Share Posted May 17, 2004 The one time I has a hot battery problem it was regulator.Putting on a Delco fixed it. Delco regulators use bi-metallic arms which actually lower the voltage when hot,this to prevent the situation you describe Link to comment Share on other sites More sharing options...
rocketraider Posted May 17, 2004 Author Share Posted May 17, 2004 Took the car on a 140 mile run Saturday with no problems. Only change was we had installed the NOS Delco VR. Thanks all for advice! Link to comment Share on other sites More sharing options...
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