Topic: Flathead turns over slow on starter


ole_Bill    -- 04-14-2011 @ 5:47 PM
  I had the all the plugs removed from my newly rebuilt flathead and spun it up on the starter to ensure I had good oil pressure. No problem. Now I have the engine reassembled and ready to run but the starter turns it too slow to start. It has a new 6V Optima battery, fully charged. I think this means I have a ground problem somewhere.....right? Where should I look? Any other posibilities?


supereal    -- 04-14-2011 @ 7:01 PM
  If the engine turned over without problems until the plugs were installed, the battery may have been depleted. Put a voltmeter across the battery and see what the voltage reads when the starter is tried. If the reading is below 4-4.5 volts, either the battery is low, or there is a big voltage drop between the battery and the starter. Put the voltmeter between the starter input terminal and the solenoid end of the cable and push the starter button. The reading on the meter will tell you if ther ia a loss, and how much. Do this to each leg of the circuit, and also be teen the engine block and the ground side of the battery. When checking, always put the probe directly on the battery terminal and not the cable clamp. If this test doesn't show where the power is being lost, i' d suspect the starter, itself.

This message was edited by supereal on 4-14-11 @ 7:04 PM


TomO    -- 04-15-2011 @ 4:45 PM
  Check that the oil pan mounting surface for the starter is not painted and that the starter is not painted on its mounting surface.

Tom


Norm    -- 04-15-2011 @ 5:22 PM
  Make sure that the battery cables are large enough. The last time I saw this behavior the car had 12V battery cables - not enough copper.


trjford8    -- 04-15-2011 @ 8:24 PM
  Make sure the battery is fully charged and follow the advice others have given you. The size of the battery cables is critical along with good grounding.


ole_Bill    -- 04-16-2011 @ 7:14 AM
  The cables are all new and they are the correct size for a 6V system. I'm checking grounds today. Lord, I hope I don't have to pull that starter (again).


TomO    -- 04-16-2011 @ 9:09 AM
  Bill, if you are sure that the starter mounting surfaces do not have paint, you can check out the grounding circuit using the same procedure that Supereal gave you to check out the NEG (supply) side of the circuit.

I would check out the NEG circuit first as defective cables or solenoid will drop considerable voltage. Even new cables can drop 1/2 Volt or more.


Tom


drkbp    -- 04-16-2011 @ 6:47 PM
  ole_Bill,

What model? Or did I miss it?

Ken in Texas


Dipper005    -- 04-20-2011 @ 7:50 AM
  Hi. Does your starter make a clicking noise when it's trying to turn the engine over?


ole_Bill    -- 04-25-2011 @ 6:06 PM
  Today I pulled the starter and took it to Chattanooga Alternator & Generator to be checked. They confirmed that nothing is wrong with the starter. Before I reinstalled it I thoroughly wirebrushed all mating surfaces so there is no paint, no rust. I think I detected a slight improvement, but the motor still turns too slow to start. I'm thinkung about trying a 12V battery. Can I hook it directly to the battery without damaging anything else on the car or do I have to isolate the starter before spinning it on 12V? Before I do anything else I'm gonna check out the voltage drop issue. Tomorrow.

This message was edited by ole_Bill on 4-25-11 @ 6:08 PM


deuce_roadster    -- 04-25-2011 @ 7:10 PM
  Bill, since you have checked out the ground side of your circuit, my guess is that the solenoid isn't passing through enough current. Inside that round part of the solenoid is a disk that comes up and makes contact with the 2 posts the heavy cables attach to. Over the years, the arcing that occurs each time it is engaged takes its toll on the contact surface of both the disk and the threaded post. I would try a new solenoid. Also, ALL the cables including the one that goes from the solenoid to the starter need to be 6v heavy ones, all 3, not just the battery cables.
Keep us posted when you find the demon...Good luck


ford38v8    -- 04-25-2011 @ 7:32 PM
  Bill, Your "newly rebuilt flathead" is tight. Once you get it started, it will loosen up quickly as the rings and bearings break in. A 6v battery will crank it fast enough if you have it set up properly, just use a short burst of ether down the carburetor to give it the initial desire.

You may also just crank with no plugs for a while longer: Henry Ford did just exactly that to "break in" these old flatmotors when they were new. It was done with an eye on a ampmeter, and when the amp draw indicated that the motor was free enough to to install in a car, it was released from the motor building with its transmission receiving a serial number.

Alan


TomO    -- 04-26-2011 @ 8:46 AM
  Bill,

While you are checking out your starter, make sure that the bracket from the starter mounting bolt to the oil pan is installed and tight.

The voltage drop check will check out your cables, connections and solenoid.

You should have less than 3/10ths Volt drop from the NEG battery post to the starter motor post with the starter engaged and the ignition off.

You should have less than 1/10 volt reading from the POS battery terminal to the starter mounting bolt with the starter engaged and the ignition off.

Any readings higher than this should be investigated by moving the probe that was connected to the starter back towards the battery.

Tom


supereal    -- 04-26-2011 @ 10:31 AM
  Does the engine turn better with the ignition turned off than it does with it on? If it does, chances are that, for some reason, the initial advance is too great. A "tight" engine that cranks OK with the plugs out says that it was probably set up correctly. A tight engine will be very hard to crank when hot due to expansion of pistons, etc, and run hot if you get it going. We have seen some flatheads that were set up with modern clearances instead of the correct specs that were very hard to crank, hot or cold. In most cases, a connection that blocks the high starter current will reveal itself, eventually, by smoking.


37RAGTOPMAN    -- 04-26-2011 @ 10:55 AM
  olebill
I think you might want to try turning the engine over,[ with ign turned OFF ]
do this with a rachet wrench and see how stiff or tight it is,
this is why the maybe starter cannot do its job,
you can jump the system with 12 volts just to get it running,
be prepared once you get it running to leave it run for a while, monitor the oil pressure and the temp it is running at, if it starts to heat up, shut it down and let it cool.
make sure you have enough gas in the tank, also
I Would put a house cooling fan in front of the radiator to aid in the break in period,maybe on a ladder or high stool,
if you can get it to run for a hour without overheating, shut and let it cool,
the next day try it again, breaking it in a little at a time, the next day it should start on its own power,
hopefully the engine rebuilder did a good job,
I have also pulled them to ge the first start.
use 2nd gear, and release the clutch slowly, and use a stout rope. let hear how you made out,,,,
my 3 cents 37RAGTOPMAN

This message was edited by 37RAGTOPMAN on 4-26-11 @ 4:49 PM


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