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Several Burned up Starters


rob.webb

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This is a problem that is not strictly a Franklin problem I suspect, but it is happening on a Franklin, so I'll start here and see if anyone has any thoughts.

My Dad and I sold a 135 Coupe that has a 145 engine in it to Eric Berg a couple months ago. He has needed us to replace the starter 3 times since then.

The first time the moving starter gear had moved all the way to the other side of the ring gear and gotten stuck. The other two times the starter had burned out internally after a week or so of normal use. All of these starters had been taken to Vogel Electric in Bakersfield, which is a very good shop and does all the electric motor work for the Nethercutt collection and many other HCCA and CCCA clients, and certified to be in good shape. When we got the broken starters back from Eric, we took it back to Doug at Vogel, and he indicated the wires inside had completely burned out and the entire starter needed to be re-wired. $600!

When I look at the wiring diagram, the starter, starter button, and battery seem to be the only thing in the circuit. The car has a standard 6 volt battery and new high gauge cables from the battery to the button, button to starter, and from the battery to the transmission for ground. I'm totally at a loss for why 3 starters seem to have been destroyed by this fool-proof system. These results are what I would expect from running the starters at 12 volts for a long time or 6 volts for a VERY long time. I need to figure this out before we run out of starters and need to start rewiring them...

Could it be that we put in wires that are too big and even at 6 volts there is too much current? Any thoughts are appreciated. Thanks!

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Just got this from Paul Fitz, reposting here with his permission. I'm pretty sure the problem is that the spark is too advanced now that I hear his explanation. Will post what I find out when Eric retards the spark.

Rob hi.

Starter motors that draw too much current and burn up are usually being over loaded as far as too much strain on them from load. It has nothing to do with cables being too big. Electric motors naturally draw more current when they get more load put on them. Load them enough and they burn out with all the current they will draw to deal with any higher then normal loads.

If you put an amp meter on the starter cable it should only be drawing about 120-130 amps for a motor that is broken-in. A newly rebuilt motor will draw a bit more, but no where near what a Franklin starter motor can’t handle.

The Series 14 motor is higher compression, but not so high that it’s going to affect the starter. They do fine until you get well over 7:1. I rebuilt Dale Balderson’s 30 Pirate to exactly a measured 7:1 compression ratio and there’s no problems starting it.

How easily does that Ser 14 motor turn over with a hand crank ? If you can turn the motor over using one hand on the crank, it’s not a mechanical problem with the motor putting too much strain on the starter.

Is the ignition timing way too advanced ? Some guys try to get more power out by bumping the advance way up. That doesn’t work on Franklins. It just beats up on the connection rods, and if too far advanced, can beat up on the starter motor because the spark is going off too soon as the pistons are coming up on compression. Too early a spark makes the motor want to turn backwards against the starter motor and the current draw of fighting against goes way up.

With the spark plugs out and the throttle open, how easily does the starter turn the motor over ? If it’s still struggling and pulling a lot of current, the starter drive may be binding, the armature shaft may be bent, or there’s still circuit problems inside the starter motor.

The foot switch contacts may be badly burned up and may not be allowing proper voltage and current flow, or other connections are bad. Do a voltage drop test (you can Google it) on each component and connection, from the battery terminals to starter motor ground at the engine mounting, and the battery ground cable too.

Let me know what you find out.

Paul Fitz

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Rob,

I think your problem is caused by the bushing, or lack of, in the crankcase. Like I said in my email, if you can send me some pictures of the bad starter and it's drive. If the bushing is missing, badly worn or you use a starter drive without the pilot on the end, the shaft can move to the side and cause a terrible drag on the motor. The shaft doesn't have much support inside the starter case and can jam up the gears. This would be a good reason for the starter gear to be on the other side of the ring gear. This kind of condition could easily cause the starter to overload and burn up.

Bill

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  • 3 weeks later...

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