New battery didn't help

[Gold Digger]

Posted sometime back about starter drawing fire off coil and some thought it was a weak battery. Well the bat was 8 years old but still whirled the engine real good. I bought a new optima bat and that didn't change a thing. So I bought a spark tester, already had a polarity tester. The polarity was right but no spark what so every until I let off the starter and while it is still whirling it sparks but not 10,000 volts more like 5,000. I have a new coil and tried it and had the same results. Just recently rebuilt the starter and done a complete tune up. Got any ideas. It will start with a 1/4 turn with the crank and runs perfect at any speed.

[Kurt in NJ]

Take a voltmeter and measure between ground and each side of the coil both with the points open, then move the engine so they are closed and measure again

also measure the voltage between the fixed point bracket and the battery ground post with the ignition on and points closed

do you have original stock ignition system ---and mention any other modifications you have from stock in the electric system

[Bob C]

What Kurt said and also measure primary voltage while cranking engine.

Bob

[Tom Endy]

Suggestion:

Remove the back floor board, remove the battery. Unbolt the ground strap from the frame. Take some rough sand paper or a sanding disk in a drill motor and clean all the paint, rust, and crud off the raised boss on the frame where the strap bolts until it is bright shiny metal. Wire wheel the strap, the bolt and the nut. While at it clean the other end of the strap and do the same to the power cable.

Tom Endy

[Gold Digger]

I'm still 6-volts and the only modification from the way Henry made it is a Nurex 6-volt alternator that has been on it for 4 years and has always performed perfect. I have already cleaned the battery terminals and the positive is bolted to the transmission. How do I measure the primary voltage while cranking the engine. This problem just started all at once.

[Mike V. Florida]

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Originally Posted by Gold Digger

How do I measure the primary voltage while cranking the engine. This problem just started all at once.

Get a set of alligator clip leads for the meter. Clip a lead on the coil and a lead to ground and hit the starter.

[Gold Digger]

The ground to the frame may be the problem. I don't know if there's a good ground to the frame and body. I've been told I was slipping a cog. I'll go run a jumper tomorrow and see if that fixes it.

[Tom Wesenberg]

My car did the same thing a few years ago. I got the hand crank out and it started on the first pull. After letting it run a few minutes, I shut it off and tried the starter, and all was well. Give your hand crank a try.

[katy]

Have you checked/cleaned all the Connections? Coil? Alternator? Terminal box? Ammeter? Distributor?

[Jeff/Illinois]

Seems like guys have more trouble than it's worth when they go to the NuRex alternator setup instead of the original

I'm not totally sold on that mod.

[Doug Linden]

I would suspect that you have frayed wires in the ignition cable that are shorting to ground. When the starter is drawing high current the voltage to the ignition drops so low the frayed wires make the loss even worse and the plugs won't fire. When you let up on the starter the ignition voltage shoots back up to normal, the flywheel keeps the engine turning and walla the engine starts. Hand cranking doesn't draw current like the starter which explains why the engine starts up.

[jmeckel]

I have posted this before. Use a good meter, hook one lead to the post of the battery that has the ground strap attached. Noe hook the other side to the grounded side of the points. Run the starter, if the meter shows much voltage at all you have a ground problem. Clean and polish each and every place there is a connection. Also run a heavy battery cable type of wire from the same frame bolt that the battery ground uses to one of the bolts that hold the starter on. Remember the return path is just as important as the supply path.

[mshmodela]

Originally Posted by Tom Wesenberg

My car did the same thing a few years ago. I got the hand crank out and it started on the first pull. After letting it run a few minutes, I shut it off and tried the starter, and all was well. Give your hand crank a try.

I've been wanting to try this and as best I can tell this video appears to me to be the best on hand cranking (or Model T) but the idea and note the arms with which he used appears to be the safest to me.....

https://www.youtube.com/watch?v=zCWnmPrxKo0

[Tom Wesenberg]

He did it the right way. Never spin the crank and never push down on it to start the engine. Only pull up.

With the right side hood open, I can pull the choke closed and pull up with my right hand. It should start on the first or second pull.

[Gold Digger]

Didn't find my trouble but it got alright all of a sudden. I seem to think it was in the distributor. I took it out and gave it the once over and put it back in. To my surprise I've got fire that will jump 3/4 inches long. I found that the rub block is worn off till the rivet is almost making contact with the cam lobes. Trying to put my finger on the problem, I haven't changed the points yet. I'm going to run it like this for a while around close to home till I find the real culprit. I might go ahead and change the points. This was a new set of points and was greased but the plastic rub block just went away. I don't remember where I bought them but from now on I want points with phenolic for a rub block.

[marc hildebrant]

Originally Posted by Jim Mason

Weak ground between the head and distributor body. hand cranking works so well because you pull the full 80amps through the points...HOT spark.

Current is limited by the resistance of the coil and the voltage of the battery (ohms law).

Thus, you wouldn't have 80 amps, but you would have more than when the starter drops the battery voltage during cranking.

Marc

[Gold Digger]

I sort of think that the upper plate wasn't getting a good ground to the distributor housing. I cleaned the spring and plate up and that was when I started getting fire when cranking.

[theHIGHLANDER]

Quick engine/start ground issue check. Run a jumper cable lead to the positive post on the battery. Turn it over and clamp the ground on the chassis or engine while cranking and see if it speeds up or makes a weak spark as you connect. Saves a pantload of time...

[BILL WILLIAMSON]

Originally Posted by Gold Digger

Didn't find my trouble but it got alright all of a sudden. I seem to think it was in the distributor. I took it out and gave it the once over and put it back in. To my surprise I've got fire that will jump 3/4 inches long. I found that the rub block is worn off till the rivet is almost making contact with the cam lobes. Trying to put my finger on the problem, I haven't changed the points yet. I'm going to run it like this for a while around close to home till I find the real culprit. I might go ahead and change the points. This was a new set of points and was greased but the plastic rub block just went away. I don't remember where I bought them but from now on I want points with phenolic for a rub block.

Excessive rubbing block wear can be caused by a loose/wobbly point arm pivot post, you can tighten it, by staking it tighter, UNDER the UPPER plate.
Bill W.

[Gold Digger]

Thanks everyone for your help and advice. It starts and runs perfect for now and I'm keeping an eye out for the real problem to reoccur as I don't think I got to the bottom of it and it fixed it self for now.