VCCA Home Forums TECHNICAL - 1945 AND EARLIER 1933-1936 36 Chevy Master will not start

Vehicle purchased a year ago with 8 volt positive ground battery and 12-volt coil. Car was able to start and run. Car would not start one month ago … don’t know why. Have done several things: Replaced spark plugs gapped at .032”, Installed new distributor cap, rotor, condenser, and spark plug wires. Points appeared to be almost new with no pitting, etc. Point gap was verified to be .018”
Changed vehicle to negative ground. Installed new 6v coil (wired from ignition switch to (+) primary post on coil with (-) post on coil going to points), Cleaned both vehicle ground straps (starter to frame & negative battery post to frame)

Engine would turn over very slowly with old 6v battery. Started using a new, fully charged 8v battery. Engine turned over somewhat better, but still not great. We supplemented both the 6v & 8v batteries with a jump from a Tahoe 12v battery without the Tahoe running (jump applied only when engine cranking and immediately removed). Engine would turn over better, but we succeeded in discharging 6v, 8v, and 12v batteries! Voltage to coil dropped to <2 volts when cranking engine with 8v battery only, but voltage was about 6v at coil when jumping 8v battery from 12v battery. Engine briefly tried to start twice, but no luck.

When disconnecting the wire from the secondary output of the coil to the distributor cap and holding it ¼” from ground, we sometimes get no spark and sometimes get a marginal orange spark (not a strong blue spark). Intermittent spark does not make sense. We also jumped around ignition switch by supplying 6v straight to the positive primary post on coil.

It seems that starter is pulling a lot of current??? Simply do not understand intermittent spark from coil secondary. This is fundamentally simple, but something is causing engine not to start.

If I read your post correctly it appears you need to take a look at the starter. 12-volts on a 6-cylinder engine should send it spinning. Perhaps the starter is dragging on the field posts or other current drawing problem. If you have a good starter to make a test I suggest you do so. After you get a good spin on the motor you can start checking other causes or reasons it will not start consistently.

Make sure that the outer condenser case is grounded. You should get a blue "snappy" spark from the center coil wire when held 1/4+" from grounded surface and points are opened and closed (or points are shorted). Also when points are open and a short is made across them the spark should be the same as when the points are opened and closed. If not the point contacts need cleaning. If you can't get a proper spark when not being cranked then you don't have any hope to have one when starter draws down the voltage/current.

You haven't said anything about fuel. Have you tried starting fluid or adding a small amount directly to the carb? Gas in the carb will evaporate over time and getting fuel from the pump to the carb will take a lot of cranking.
Is there gas to the fuel pump? Pump to the carb? If no, then either the pump diaphragm is bad or the check valve (wafer) in the pump is stuck.

What size is your positive battery cable? For maximum cranking power on a 6 volt system you should have either a "00" or a "0000" 6 volt cable and your 6 volt battery should be a minimum of 600 cold cranking amps.

I think your starter is the culprit. It is drawing too much current and not leaving enough to properly fire the ignition system. As Chipper says above, remove the cap and short across the points or open and close them by hand to see if a good spark results. If so, it's a good bet your starter is dragging. Good luck. Let us know what you find.

Mike

First thanks for all the help so far. When we direct wire from battery and do the tests mentioned we get a nice blue yellow spark. I took my starter to a repair shop and sure enough at 6 volts it would not work but with 12v it spun. I will know more about the condition later this week. Hopefully with the starter repaired I can drive this thing soon before winter sets it "grrrrrrrr" Again thanks for the help and will post if the starter fix worked. Bill