Model A starter clunk then no electrical
 

Hi everyone. First post here and I'm not an expert. Thanks in advance for your advice and patience.

I've a 1930 Model A. Has 12V conversion.Worked perfect for 2 years. Last week went to start and likely pulled up too early on the starter, heard the "clunk" I've read about here, then no electricity (starter, lights, nothing). Battery indicates 12V. Fuse between starter and junction is intact. Per posts here, tried pushing backwards in 3rd gear. No clunk after full rotation of the engine. Testing voltage where battery cable connects to starter, no voltage.

I removed starter switch (taking starter out of the circuit) and connect battery cable to wire to junction box through fuse), I have lights again. What does that indicate? Is my starter toast and has a short? Get a new starter? If so, do I get a rebuilt? Do I need a special starter because I have 12v? Thanks again all. Tom

Re: Model A starter clunk then no electrical
 

Measure voltage at battery terminals. Then measure from +12v battery post to the frame. Should be 12 v, if not bad cable, loose battery cable connection, or terminal on cable , and the connections on frame for the cable need to be cleaned.


Then measure from - battery post to starter cable connection, should measure 12v, if not same as above - bad cable, loose connection, connections need cleaning.


Do you have a Master cutoff switch - perhaps bad switch, bad connections.

Re: Model A starter clunk then no electrical
 

Tom,
You say no voltage at starter end of cable. I would check the cable for corrosion in the lug connections, that can be a problem with the heavy current draw from the starter.
If the starter is bad then you may need to find a local shop that rebuilds them, you are not likely going to find a 12v Model A starter at your local auto parts store. Also do you have a local Model A club that could help.
Ed

Re: Model A starter clunk then no electrical
 

X2 what Ed said, dirty of bad cable.


Bob

Re: Model A starter clunk then no electrical
 

Hi all. Thanks much for the speedy help! The battery definitely has 12V (I tested w cables detached.) The cables are fine and the cutoff switch is fine. I've confirmed all.

The starter end of the cable is 0 _only_ when its connected to the starter switch. If I disconnect the cable from starter, I have 12v at the starter end of the battery cable.

With the starter removed from the circuit (connect starter end of bat. cable to the line to the junction box ) I have 12V. Lights, horn, etc all work.

But if the starter is IN the circuit, I get 0 at and beyond the starter. That seems to indicate the problem (a short?) in the starter. And if you agree, and I need a replacement starter, do I have to get a special one for 12V?

Re: Model A starter clunk then no electrical
 

Here's a photo showing how I've removed the starter from the circuit, and connected the starter-side battery cable directly to the wire to the junction box. In this state, I've got 12V through and all electrical is restored. So battery terms, cutoff, cables and fuse are all OK. That's why I think the problem is the starter...

Re: Model A starter clunk then no electrical
 

If you're getting 0 volts when the cable is connected to the starter you have either:

A.) A cable that is somehow failed open circuit - but may be sensitive to "position."
B.) A short in your starter switch or in the winding of the starter motor which is pulling down the voltage to zero. A condition which SHOULD cause blue flash, smoke, heat, and a whole lot of damage and possibly a fire. There is a lot of energy in a lead-acid battery which you are short-circuiting.

Try jumper cable going directly from the battery post to the starter switch attachment. Next try the jumper cable between the battery post and the "knob" underneath the starter switch (remove the two screws and take off the starter switch.)

If you get a HUMONGOUS spark and the jumper cables start to catch on fire you know your starter motor is toast.

Or you get a medium spark and the starter motor starts and you are among the lucky and only have to diagnose a problem with the switch or cable.

Joe K

Re: Model A starter clunk then no electrical
 

If you have a short in the starter that brings you down to zero volts, something must be getting hot, tap that end of the cable to ground and see if you get a very big spark. You should. If not, it could be the crimp of the end fitting to the cable wires.

Re: Model A starter clunk then no electrical
 

Can't believe how helpful everyone is even on July 4th. I wish I could buy you all a burger and a beer. :)

I just did what Joe K suggested: "try the jumper cable between the battery post and the "knob" underneath the starter switch (remove the two screws and take off the starter switch.)"

Tapping the knob with the cable produced a medium spark but when I held it on for a sec, the starter turned! So it appears to be working.

Re the starter switch, using a voltmeter there doesn't appear to be a short. I get no continuity between any part of the casing or rod and the copper flap. They seem to be correctly electrically isolated. See pic.

But if the starter turned, it seems to imply the switch. But it's pretty simple. I don't know what could be actually wrong with it.

Re: Model A starter clunk then no electrical
 

It may be the traditional "restorers dilemma" - no starter motor ground - as in the path from the starter BACK to the battery is somehow "painted" or otherwise made non-conductive.

VERY common among restored cars - the mounting flange for the starter is painted and the bolts are not a great current path.

Re-establish a correct current path on the mounting flange of the starter motor and you may be fine. This might be tested as a malady by landing one connection of a single jumper cable TO the starter somehow (the frame bolts MAY work) and the other on the ground post of your battery. (I have not identified either as plus or minus as it does not matter to the issue at hand and you might or might not be "positive ground.")

Note that you're having current to "accessories" via the yellow wire and this works is a sign THEY have their own separate ground paths - and those are OK.

Joe K

Re: Model A starter clunk then no electrical
 

I would still try a different cable.


Bob

Re: Model A starter clunk then no electrical
 

Use a jumper cable to make sure the engine is grounded. Most of us have a second ground cable between the frame and bell hsg. Sometimes that engine does not have a good ground.

Re: Model A starter clunk then no electrical
 

Thank you Joe. Per your advice, I confirmed a good current path between starter and battery. (By the way, battery positive post goes to the starter, neg to the frame (through cutoff switch), so negative ground).

I took the starter switch apart and confirmed everything was electrically isolated as it should be. The little rubber "T" pin that pushes the copper flap seemed fine.

Put the switch back on the starter and dang: No electricity to anything again. Voltmeter testing showed elec. continuity between the switch casing (or any ground) and the brackets that hold the starter switch fuse. So something's shorting.

I took the fuse out. I tested continuity again between ground and the _starter_ side of the fuse and there was none--it was correctly isolated. So now it seems to be something on the junction box side of the switch fuse.

So
1) If i connect the starter battery cable directly to the wire to the fuse setup, without the starter, I get lights, horn, etc.
2) If I connect the starter back in with the fuse in, I get (bad) continuity between ground and anything positive (e.g. starter post or fuse brackets).
3) Remove the fuse and what should be electrically isolated is again, at least on the starter side of the fuse.

So I think this means the problem is in the junction box or coil?

(And as nice as you guys have been helping me today, please know this can wait for after your July 4th parties). Tom

Re: Model A starter clunk then no electrical
 

Just a note re adequate grounding and such. I think all that's OK. The car has been incredibly reliable and started every time for the last two years. This all started a few days ago when I think I let my foot off the starter too soon and heard that unusual clunk.

Re: Model A starter clunk then no electrical
 

Check and see if the bendix is jammed.(Strange Clunk noise)
Clean and file the copper button and the strap in the switch.
carefully inspect the post coming through the switch housing to ensure it is not grounding on the cover.
Check the starter motor mounting for rust preventing a ground path.
I still find it odd that with a short to ground you see no smoke or heat build up on any components of the system. Possible the cable to the switch from battery or battery is bad.

Re: Model A starter clunk then no electrical
 

Thanks for all those points, Farrell. Re your suggestions:
- cleaned the switch and starter post
- checked the switch every which way for short. all ok. Post for battery cable has 3 insulated washers between cable and the switch housing.
- No rust on the mounting.

I actually started this whole thing thinking it was the Bendix. I pushed the car backwards and forwards in 3rd gear and ensured I made a whole engine rotation (watched the fan blades). No clunk.

And when I connected the starter directly to the battery positive, it did turn. Don't know if that means the Bendix is not jammed.

One thing I don't get is why would a jammed Bendix cause the electrical issue I'm seeing?

Re: Model A starter clunk then no electrical
 

Sorry, but I get lost trying to wade thru this discussion. One problem is I suspect that the terms "short" and what might be called a "bad connection" or "open connection" are being used interchangeably. A short means there's an electrical "short-cut" or path around the intended load (lights, horn, etc.) from one battery terminal to the other. As others have suggested, a short is unmistakable--smoke, sparks, heat, fire!!! or a blown fuse. WHile it's true that certain voltage readings may drop to zero during a short, that will usually be the least of your concerns!

Re: Model A starter clunk then no electrical
 

Building on what steve s wrote, to me the connector on that battery cable in the picture in post 6 looks kinda crusty. Bright and tight is the way to go on electrical connections. Wire brush that connector and the stud on the starter switch. Corrosion is like insulation.

Re: Model A starter clunk then no electrical
 

Steve, Will (and everyone else) I appreciate your taking the time to wade through all I wrote. I was trying things as you fine people were providing advice.

You and others are right in that when I see no voltage I'm calling it a short yet there is no heat, smoke, etc. (which is good news). So I agree it's just a zero voltage and likely a bad or open connection. I did wire brush the copper switch bolt and the connector after the photo but I'll do it again when I'm done earning the pay I might need to fix this. Tom

Re: Model A starter clunk then no electrical
 

A trick that works very well for me on making up battery connections is "conductive grease" that electricians use for aluminum wire.

No-Al-Ox is the name and its basically a grease with fine particles of graphite - and is used normally for aluminum wire landings in copper binding screwpads.

Available at the big-box stores and they may have other names/sources for basically the same product.

Don't get it on your clothes. And wipe clean around the fitting when you've tightened it lest it provide a start for a conductive ground path.

Joe K