VCCA Home Forums TECHNICAL - 1945 AND EARLIER 1929-1932 Help diagnosing starter problem

Tried to start my 31 sport coupe. Pressed the starter and it cranked a few times Sounded like it was working but not smoothly, almost as if I was pressing the starter button, and lifting and then pressing in quick succession, like it was not engaging smoothly. I lifted off, waited a few seconds and tried again, and nothing. No noise, no movement. Just a slight 'hot electrical smell.' Can anyone give me pointers on how to diagnose the problem? The repair manual has some suggestions starting on page 206. The book says to test armature with a growler, whatever that is, or examine the armature, or other things that sound like the starter must be disassembled. I would first like to see if I can find the problem before I remove the starter from the engine.
The battery is fully charged. The lights turn on. The gauges jump to life when I turn the ignition to on. It is still a 6 volt system and has worked well for the last nine or so years since the car was rebuilt. The starter was not rebuilt when the car was rebuilt as the starter worked well.

Thanks.

Jim.

First place to look is the connections to the battery. They need to be squeaky clean. Next is the starter switch. The battery to cables, cables to starter switch terminal and starter switch to starter are critical to proper starter performance.

I remember watching the shop at my grandfathers dealership use a growler. It was an electrical instrument with v shaped cradles that an armature would lay in. The mechanic would rotate the armature within it and the growler would emit a growling noise as it was rotating. I believe there was a gauge on it that would show defects in the armature as it was rotated past them.

Sounds like the starter drive may have a broken spring or spring attaching bolt. If the battery and electrical connections are good it's time to pull the starter and check it.

In my estimation there are five possibilities (in no particular order):

1. The "solenoid" is worn so power from the battery is not transferred to the starter.
2. Bearings in the starter are worn to the point where the armature contacts the field coils.
3. The starter brushes are worn out.
4. The armature is toast.
5. Battery terminals or cables are corroded.

With all due respect to Steve D, I don't buy the broken spring/bolt. I've had a bolt break twice and all that happened was that the starter spun but the engine didn't.

All of that said, read my sig.

There is no solenoid on a 31 starter. We are tied on starter spring bolt breakage. The first one did as you posted =spin and no engagement. On the second the bolt backed out partially and was catching the drive end housing intermittently. It acted like a bad battery-would turn over slightly then stop . Both a friend and James Peterson (I had recently installed his regulator) thought it was a bad sulfated battery even though it was only three years old. I put in a new battery and it worked fine the first try then did the same as previous. I removed the starter and found the rear spring retaining bolt loose and the head worn as it had been rubbing the inside of the drive end housing.

I will work from least onerous to most difficult. Something tells me I will need to remove the starter. What is the best way to check when the starter is off the engine?

If it was not rebuilt when the restoration was done and that was nine years ago I would just remove it and take it to a GOOD rebuild shop.

I had a "slow starter" problem with my two 31 chevs that I restored. I did take them off and took them to repair shop. They went threw them and they were fine, They did take off ALL paint on any castings that butt up against each other, the barrel and both ends and even bolts,. They also told me to sand or buff the flywheel housing where the starter bolts on. I did not have much faith in it working, but they spin over about like a 12 volt system now.

That's why I put it in quotes. Not sure what else to call it.

At any rate, it's pretty easy to remove the starter, probably 10-15 minutes. Taking it apart is pretty quick too. Putting it back together is quick. The only trick is to make sure that the brushes are pulled back so that the armature goes all the way in.

They are pretty simple DC motors. Clean up the years of gunk. Clean the armature using emory cloth, replace the brushes. Check the bearings for wear. Check the "bendix" (again I don't know what it's really called) to make sure that the spring isn't broken and the bolts are tight.

If the bearings are worn, you should (obviously) replace them and take the armature to a motor shop and have them turn it and undercut it. If you have a lathe, you can do it yourself. Take just enough off to make it round, then undercut the epoxy (or whatever it is between the blades of the armature) a tiny bit. I've used a hack saw blade to do the undercutting.

You don't undercut starter armatures. Turn only.

Why? My autoshop teacher in the 1800's had us undercut both.

Some manufactures recommend cutting and others do not. I think those that do not recommend do so to eliminate improper cutting. It needs to be cut away clean with no raised edges on the sides which will break off . Also you should not use emery cloth for polishing the commutator as the emery can lodge into the soft copper and cause rapid brush and commutator wear . As written by William H. Crouse published by Webster Publishing Division of McGraw-Hill Book Company Fifth Edition 1963.

I've seen exactly that on a few starters. There is supposed to be a washer with bend tabs on it to prevent the bolt from coming loose but most are lost the first time the drive is serviced and who knows how many times our starter have been serviced in 85+ years.

On the undercut issue; I have a small electric motor that mounts on my lathe with a small cutting wheel. It is designed to cut the mica and does so perfectly. You set the depth, rotate the armature, then simply roll the carriage down the ways of the lathe. It was made by Atlas for Atlas brand lathes but does the same job on my logan lathe.

The brushes in a starter are typically copper, and if you undercut the armature, the slots will fill up with copper and short the commutator out. The starter will draw way too much current and barely turn. Then you will have to disassemble the starter and clean the grooves out. On a daily driver, it lasts about 2 weeks to a month. Not recommended.

Generators should be undercut.

Yes, don't undercut the starters. I'm thinking generators when I use my motorized cutter.