Technical Starter dead?

[Veloman518]

Just got the ‘70 500L. Had some serious fuel issues so I replaced the tank, fuel lines and rebuilt the carb. Ran like a champ for about 2 days. Then I started having electrical issues. #2 plug was arcing (cause the damn thing zapped me when I touched it). Sort of got that squared in anticipation of replacing a good bit of the dusty old parts. Then it left me sitting about 5 miles from home. Sputtering misfiring. I wrote it off to the electrical issue but then spent a day just trying to get it running well enough to cover the last 5 miles. I think I may have murdered my starter. Originally fired up fine but as I stubbornly kept working it sounded worse and worse until I got nothing. Towed it home and rolled it in the garage. Charged the battery and tried again, slow turning and lots of groaning. Battery was very old so got a new one. Put it on the charger for 2 days and worked on rebuilding the starter. Didn’t look too bad although the bromze bushings were suspect. All complete and benched it. It spun but sounded pretty awful. I remounted it anyway thinking if it fired up even once, I would know the starter/battery was likely the culprit. Same thing. Weak cranking and no start. I can turn the motor by hand so that seems ok. Should I just eat a new starter?

 

[F123C]

^^ No, too soon to buy another starter.

https://mrfiat.com/italian/fiat/fiat-500/electrical-and-ignition.html

^^ have reconditioned starters for the 500L ($388 - too dear imho)
but they also have starter motor parts.

When you stripped and reassembled your starter, it turned but groaned.
You reckoned the bronze bushings were suspect. As you probably know, worn bushings can allow the armature to make contact with the field coils, causing the starter to turn slowly and make a groaning noise.

I'd suggest:-

check there's no damage to the armature and field coils,

get new bushings ($12 pair) from the above supplier, (soak them in engine oil for 24 hrs before fitting if they're the porous/sintered type)

maybe fit new carbon brushes ($6 each)(as the brushes wear, the brush springs can hang up on the brush carriers, preventing good contact between the brushes and commutator segments - leads to commutator burning),

check the starter motor switch (on the body of the starter motor) for excessive resistance (it's contacts can get burnt),

ensure you've got a good ground connection between the engine and body,(iirc, it's a braided cable between the generator? and body)

then try the starter again.

There's a free download of the official Fiat shop manual (which includes how to check the armature and field coils/windings etc.) available in the Downloads section (see the blue band at the top of this page, click downloads, scroll down and click on 500 Classic).


Hth,

Tostal.

 

[Toshi 975]

Great advice you have had already . I would say get new bushes and new brushes even if the old brushes are not completely worn out but worth doing while the starter is apart. Also new brushes can sometimes be a little tight in the holders so make sure they slide easily under the pressure from the springs. They can be sanded down a little if not. I also tend to take a small strip of wet or dry and wrap it around the commutator holding it in position with one hand and turning with the other just to make sure the commutator is shiny clean.

 

[Veloman518]

Here's where I am so far



^^ have reconditioned starters for the 500L ($388 - too dear imho)
but they also have starter motor parts.

When you stripped and reassembled your starter, it turned but groaned.
You reckoned the bronze bushings were suspect. As you probably know, worn bushings can allow the armature to make contact with the field coils, causing the starter to turn slowly and make a groaning noise.

I'd suggest:-

check there's no damage to the armature and field coils, Did resistance tests and all seemed consistent. Not sure what actual values should be but .2 ohm (or .02? can't remember exactly) between bars was what i was getting on the commutator, full resistance between commutator and shaft. Cleaned between the bars and polished the face

get new bushings ($12 pair) from the above supplier, (soak them in engine oil for 24 hrs before fitting if they're the porous/sintered type)This is my focus I think. There is just the slightest play but it sure is noisy when it turns. Not a smooth whirring sound. I'm referring to bench testing in a vise. I can pull the starter switch and it makes good contact but it's more of a squealing that that nice smooth sound.

maybe fit new carbon brushes ($6 each)(as the brushes wear, the brush springs can hang up on the brush carriers, preventing good contact between the brushes and commutator segments - leads to commutator burning), Brushes didn't look too bad with plenty of material left.
polished the faces

check the starter motor switch (on the body of the starter motor) for excessive resistance (it's contacts can get burnt), Cleaned all the contacts on the switch and the body of the starter

ensure you've got a good ground connection between the engine and body,(iirc, it's a braided cable between the generator? and body) Need to find the ground cable. Nothing attached to the generator other than the 2 electrical connections. I'll find the ground strap although the starter was spinning fine while it was stuck until i ran the original battery down. New battery is showing 13.3v btw

then try the starter again.

There's a free download of the official Fiat shop manual (which includes how to check the armature and field coils/windings etc.) available in the Downloads section (see the blue band at the top of this page, click downloads, scroll down and click on 500 Classic).I have that and the Haynes


Hth,

Tostal.[/QUOTE]

 

[Veloman518]

Some pics. Trying to load a video of the bushing slop

 

[Veloman518]

https://1drv.ms/v/s!AmgL3NQJL4nj8ws8julX5rxpmOMt

 

[fiat500]

https://1drv.ms/v/s!AmgL3NQJL4nj8ws8julX5rxpmOMt

Obviously that's very bad. I think that when I was supplied new ones there were two different diameters of bush in the pack; could the wrong one have been fitted at some time or is that all down to wear and tear?

 

[Veloman518]

I just got the car but the starter was pretty beat up looking. I’ve already disassembled, cleaned and painted it once. It looked much worse.

 

[fiat500]

I just got the car but the starter was pretty beat up looking. I’ve already disassembled, cleaned and painted it once. It looked much worse.

You've done well to get stuck into that then. I bought a reconditioned starter a few years ago; it looked great, with fresh paint and a brand new cover on the brush-holders and rubber cover on the lever. Within a couple of months it went the same as yours...the brass bushes had obviously not been replaced. One of them was spinning in its housing as well as being worn. I fitted new ones using Loctite and replaced the dust-cover on the brushes with a genuine one from another motor as it wasn't big enough and let dust in.

The torgue of turning it gave once I had rebuilt it took me by surprise and the engine started immediately...it's a very worthwhile job to do.

 

[Veloman518]

Back in business. Bushes replaced, new armature and brushes. Replaced all of the ignition bits too. Fired up nicely. Pouring rain here so will get it on the road this weekend and see how it does.