1967 Battery drain after running 10 minutes

[Keith B.]

I started my car for the first time since the motor has been rebuilt. I am attempting to break in the cam properly so I set the RPMs and after 10 minutes the motor simply shut off. When I tried to restart the battery was completely dead. This happened to me twice and I had recharge the battery to full. I went and exchanged the battery after it failed. I got a brand new battery and it was fully charged when I started. It won’t even click the starter now that it has shut itself down.

Could this be the voltage regulator? It is original and was not restored. Do I have a short somewhere? The alternator also was rebuilt as a part of the restoration. I also have an original 264 coil that I am using. In a previous car when the car got warm after driving for a period of time the coil shut the motor down, but it didn’t have an impact on the battery.

Any suggestions on what could be causing such a draw of voltage away from the battery so quickly. I could tell that the battery was starting to go after about nine minutes of running as it started to have the RPMs vary by about 150 and then it simply just shut down. Any suggestions would be helpful at this point. I need to be able to test certain things if there are ways that I could do so.

[Leif A.]

Keith,
Have you checked the voltage output at the alternator and voltage regulator with the engine running? What is the voltage at the battery when the car is running? Certainly sounds like the alternator is not putting out enough volts or the voltage regulator is not regulating correctly. I'm going to hazard a guess and say it's the alternator. Once the car is started, the alternator takes over the voltage duties versus the battery (which is there basically to start the car). Battery shouldn't run down that quickly.

[Bill S.]

First start simple and go forward. 1st step: confirm the new battery is good. It must read at least 12.7V under load. Don't just put a Multi Meter on it, test it with a carbon pile tester that puts the battery under load and tests it. If the battery checks out as good and it won't start the car then you have a dead short somewhere. By the way most decent batteries have a 100 minute reserve capacity (100min RC) so even if you alternator was stone dead, if you started the car and ran it just on the battery it should last more than an hour. 10 minutes tells me you have a big drain on the battery.

[Keith B.]

Update- After I had the car running and it shut off I tried to start it again and it was a very sluggish try on the battery and the starter. Then it would only click. I recharged the battery overnight had 12.8 V at the battery went to the ignition to turn it on to test the alternator and didn’t even get a click at the starter. It was working fine yesterday. I checked the wires underneath and everything is tight and it’s not near the exhaust Manifold. I have an NOS solenoid and the starter was rebuilt. I am not even getting a click now. I want to be methodical about how I check this I really just wanted to see if the alternator was not functioning correctly but I think there is something else that is draining the power down.

[David H.]

Keith

Have you done a load test of that battery?

Dave

[Keith B.]

Brand new battery yesterday. Had it tested before I left Autozone

[Keith B.]

The amp meter in the car pegs left when I turn the key. I have blower motor function on that side of the harness. Thinking solenoid or starter. Thoughts?

[Keith B.]

I think I might have found it! What would cause the link to melt? Where can I buy the usable link to repair this?

[David M.]

Repair the melted wire harness. Use solder and shrink tube, not butt splices or scotch locks.
Do you have a decent VOM(volt/ohm meter)? If not get one before you do another thing.

If that melted wire harness was not caused by exhaust manifold/head pipe contact then something shorted, pinched or is not grounded.
You yanked the engine so something got disturbed or not assembled right.

Bench test the starter.

Are all the engines factory ground wires & braided straps intact and tight?
Is the engine block to frame ground strap on the passenger side engine mount present clean & tight?
Does the voltage regulator (VR) have a separate case ground down to the frame? It should. Are the VR connections clean and tight? Push in on the flat connector at the regulator to make sure its seated. Remove it look at the back side for burns. Remove the lid look at the contacts and coils for burns.

Whats the condition and age of secondary starting system cables(large battery cables)? Including the factory block to frame wire. Are they clean and tight on both ends?
If they are 58+ years old they likely need to be replaced. Check the resistance. They can visually look OK and not be. High resistance (Ohm) readings = bad cables.

Recheck connections at the battery/starter/alternator.
With the VOM connected across the battery posts start the engine. It should read a minimum of 13.8 VDC at idle. Max is ~14.2-14.4. If the readings are not between these two, then we can get into regulator/alternator trouble shooting. Its easy and I can walk you through it. Dont throw parts at it until you know whats wrong.

Safety note: Get a battery disconnect switch. Install it on the negative battery post. Disconnect when ever you get out of the car.
Its a good anti theft device and could save your car and life especially if you have a garage connected to your house. Get the 25 dollar one not the 8 dollar harborjunk offshore junk.

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[Keith B.]

I have the switch blade type of disconnect. Working on putting the wires back together. Had another wire harness an borrowed two wires that were damaged beyond repair. Starter and solenoid bench tested with good function. Will be putting back together tonight. I believe this was from a short I created by having the oil pressure line touch the ballast resistor. Hoping once harness is complete I will be back in good shape. Thanks

[David H.]

...Hoping once harness is complete I will be back in good shape. Thanks

Keith

If you've found and corrected short, please comment back on this thread. Closure, may help others in a similar situation.

Dave

[Keith B.]

Back to the original issue. I fixed the wires put the starter back in the car hooked the battery up. No starter no click. Looked down and the battery gauge went from strait up to peg to the left. Immediately disconnected the battery and the gauge returned to the middle. I did have interior lights and clock running. What am I missing?

[Keith B.]

Back to the original issue. I fixed the wires put the starter back in the car hooked the battery up. No starter no click. Looked down and the battery gauge went from strait up to peg to the left. Immediately disconnected the battery and the gauge returned to the middle. I did have interior lights and clock running.

Disconnected the starter and jumped from the battery and have the same results. Ruling out the starter and solenoid.

What am I missing?

[Don H.]

For continuity in helping resolve this electrical issue, I merged the two threads, and I deleted all the posts about battery cut off switches.. Mr. Burmeister said he has a cut off switch on his battery.. Something else is wrong.

[Mark F.]

Back to the original issue. I fixed the wires put the starter back in the car hooked the battery up. No starter no click. Looked down and the battery gauge went from strait up to peg to the left. Immediately disconnected the battery and the gauge returned to the middle. I did have interior lights and clock running.
Disconnected the starter and jumped from the battery and have the same results. Ruling out the starter and solenoid.
What am I missing?

Keith,

Does your ammeter peg to the left with the ignition in the accessory position (not full clockwise to the start position) ?