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Discussion Topic:
1936 starting problems
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voced |
07-25-2022 @ 5:50 PM
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Member
Posts: 86
Joined: Oct 2009
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What should the voltage be at the starter when trying to start the car? I took all the grounds off made sure the paint is gone. Even took the starter off and cleaned all the areas. What about going to a 8 volt battery? It is a shame that I have such a nice car and can't enjoy it, because it might not turn over good enough when I get there. Embarrassing.
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carcrazy |
07-25-2022 @ 8:20 PM
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Senior
Posts: 1587
Joined: Oct 2009
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The results from a Google search for hard starting when hot follow: Bad cell or internal connection inside the battery. Bad connection to a battery terminal, the starter solenoid (either side) or the starter. Starter internally shorted when hot. Here are some other possible causes: Clearances within the engine are too tight when hot reducing cranking RPM. - was the engine recently overhauled? Valve clearances are too tight so valves don't fully close when hot which reduces compression to the point where the engine won't start. Failing coil when hot does not provide sufficient spark to start engine. Vapor lock due to gasoline boiling in the fuel line impeding the flow of fuel to the carburetor. Faulty fuel pump or vacuum leak at top gasket of fuel pump. Leak in fuel line between fuel tank and fuel pump. Fuel line located too close to exhaust pipe allowing fuel to overheat. Two backup items you can carry in the car at all times are starting fluid and jumper cables. Use of these will usually allow you to start the engine unless it has no spark.
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carcrazy |
07-25-2022 @ 8:23 PM
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Senior
Posts: 1587
Joined: Oct 2009
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Do not go to an 8V battery. This is a band aid that causes many more problems than it can possibly remedy.
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voced |
07-26-2022 @ 4:57 AM
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Member
Posts: 86
Joined: Oct 2009
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Thanks Carcrazy: It happens even if not hot. It also happened before I rebuilt the motor. It runs like a clock. Sometimes it turns over perfectly and 3 out of 4 times it just grunts like a low battery. It has been frustrating considering that I have added grounds, and replaced every item that could cause this. Thanks again for your ideas. Jerry
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carcrazy |
07-26-2022 @ 10:52 AM
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Senior
Posts: 1587
Joined: Oct 2009
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What has not been changed? You have changed almost everything that could possibly be causing your starting problem. When you crank the engine with the starter, does the RPM vary like the flywheel ring gear could be out-of-round? If the engine cranks slowly when trying to start and all of the electrical system checks out as being good, the problem could be caused by excess friction somewhere. When you go to start the engine, do you have the clutch pedal depressed so the engine does not have to rotate the transmission input shaft and gears? If the transmission gears are being rotated while you try to start the engine and you are using a high viscosity oil, the engine will turn over more slowly. You might want to use SAE 90 weight gear oil in the transmission.
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37RAGTOPMAN |
07-26-2022 @ 2:40 PM
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Senior
Posts: 1941
Joined: Oct 2009
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SLOW TURNING ENGINE, did you try turning the engine over with a hand crank , cold then hot ???? let us know, thanks 1937 Ragtopman
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carcrazy |
07-26-2022 @ 5:27 PM
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Senior
Posts: 1587
Joined: Oct 2009
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One way to check to see if the valves are closing all the way is to do a compression test. Good sealing of the valves is required to provide adequate compression to start the engine. Warm the engine up to operating temperature before removing all of the spark plugs (if you have cast iron heads) and do a compression check while the engine is hot.
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JayChicago |
07-27-2022 @ 8:14 AM
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Member
Posts: 471
Joined: Jan 2016
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A reminder: As I understood the posts here, problem is not hard starting, problem is intermittent slow cranking.
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carcrazy |
07-27-2022 @ 12:04 PM
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Senior
Posts: 1587
Joined: Oct 2009
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Slow cranking could be caused by excessive friction in the engine. Does your engine have the poured Babbitt bearings or the later type of insert bearings on the crankshaft? Because your slow cranking problem is intermittent, suspect something is changing within the engine from time to time. Is the oil clean and free of contaminants like dirt, metallic particles, anti-freeze and water? Contaminants getting onto the bearing surfaces will increase the friction and slow the cranking speeds. If you have the poured Babbitt bearings, the contaminant particles will get impregnated into these "soft" bearings and allow a reduction of the friction to temporarily restore proper cranking speed.
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TomO |
07-27-2022 @ 4:57 PM
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Senior
Posts: 7243
Joined: Oct 2009
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A rare cause of your problem could be a bad distributor rotor. Remove the inner caps and see if you can rotate the rotor. If you can have the distributor serviced. Worn or bad points can also cause changes in timing that cause the the engine to buck the starter. Do a search for Voltage Drop , all topics and ALL in the past box. Basically you should not see more than 0.6V drop from the NEG post to the starter when cranking the engine with the ignition off. The POS post to the starter mounting bolt should not exceed 0.1V If the grounded voltage is high, your starter is drawing too much current. You can make these tests on a warm engine and should get results even if the starter cranks normally.
Tom
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