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Starter Bench Testing


Tom Skinner

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Gents,

I recently purchased a Starter for my 1948 Chrysler Royal. It is a Auto-Lite MAX4050 6 Volt (correct for the car) and came with the Selenoid. I was fortunate enough to get a clean one in good shape. I can see how to change out the brushes and have read "how to do them" in my Service Manual. I live in Hunterville N.C.. My question is: What kind of equipment is required to Bench Test a Starter? The several places I have called in nearby Charlotte N.C. do not do it anymore. When I first moved here back in 1979 with my first 1948 Chrysler Royal two places did them, but unfortunately the old timers that did them are gone now, and so is one of the shops. The remaining one is run by the grandchildren that have no knowledge of how to bench test a Starter. I am also ignorant as to how to do this. Any suggestions would be appreciated. I have already searched the Technical and Resources Sections of our Site. Beyond googling a place to send it to, I would rather carry it to someone to watch them do it and learn, or learn how to do it myself with any necessary equipment I may need to build or purchase. Let's face it these skills are going away, and we need to "carry them on" to the next generation. Any help is appreciated. Thank you in advance.

Tom

 

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I "bench test" mine by clamping a jumper cable to the hot post and then use the other jumper cable to touch the mounting plate area. If the starter drive moves smartly and spins vigorously,it's "bench tested".

There are load testers you can buy to get specific numbers,but I never bothered with them. If the starter drive travels back to the rear and spins fast with enough torque to want to spin the starter body around on the floor,it will start the car.

If that isn't want you want to know,do a web search for "starter test equipment". AFAIK,all the test are the Amp draw and the RPM's,so it using one can't be any more complicated than my floor test. One cable goes to the hot stud and one goes to the ground.

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the book has all the specifics for testing the starter motor free of the engine and on the bench...free run speed, current draw and voltage drop..unfortunately not many folks have the resistor, torque gauge or amp gauge laying about that will handle up to 500 amps. nor a direct read rpm gauge for verifying rotational speed at free run.  Quick tests as knuckle points out are mainly used at home and can point out some problems.  Usually worn brushes but more common is the elongated rear bushing.  The bush wear will cause the armature to drag on the field and cause excessive amperage drain on the battery and in car test can usually indicate this problem by rapid heating of the battery cable and slow turning of the engine...a amp draw test with a clip on meter would be good test here, these inductive meter wee not available back in the days these book were written.  Don't rule out the voltage drop that could be in the cables itself indicating starter problems, this test is easily performed at home also.

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As noted above its doesn't need to be rocket science to test the starter. I use the jumper cable method with a good battery of proper size and rating and judge the effect when connected. 6v starters are a little slower to respond than 12v. As long as the starter spins quickly and the bendix extends its probably good to go . The best test in installed on the car. Just my 2 cents. Good luck. Neil

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Many of the parts houses offer free starter and alternator testing so you could try them and most are going to do the same kind of testing knuckleharley has described.  Try an implement dealer if you can find one.  Some of those will still rebuild starters and generators for the older equipment and will still have the equipment and tools to do so.

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4 minutes ago, Tom Skinner said:

Thanks!

I will try the Knuckleharley test as soon as I finish cleaning the Starter up and change out the Brushes. I'll get back with the results. I am not going to do much today. Happy Father's Day to all.

Tom

Plymouthy Adams pointed out something often overlooked when it comes to starter problems,namely the battery cables. This can be a huge problem for these old 6 volt cars if a previous owner has replaced an original cable with a auto parts store cable typical for a 12 VOLT system. 6 Volt systems draw a LOT more amps than 12 volt systems,and the thinner cables can quickly become brittle. Brittle wires just get hot,they don't transfer any amperage Check both of your battery cables after you are done cleaning and installing your starter. IF the cable going to your starter from the battery seems very stiff,cut a little insulation from either end and check to see if the wire is corroded/discolored. If it is,don't waste any time fooling with it. Take both cables off,throw them away,and buy very thick gauge cables made for 6 volt positive ground systems.  I say positive ground systems because the positive cable end will be smaller than typical for a positive battery cable,and the ground cable battery end will be much larger because it goes to the positive battery post.

I can't remember what gauge cables are recommended right off the top of my head,but I am sure someone else will pop up and tell us both.

Also,while your starter is apart do NOT neglect the bushings in each end. They wear out and when they do,you are only getting part of the amps you need to spin the starter. If it were me,I would only buy these from a NAPA store because that way you can be almost certain to get a oilite bushing and not some cheap,thin crap made in china out of brass-coated tin.

Also,don't forget to put a thin coat of wheel bearing grease on the starter shaft while you have the starter off the car..

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I'd be interested in what the AB starter repair kit consists of  for the 1942-48 Chrysler and Desoto starters .

Most all of the wear/ trouble with those style starters is in the solenoid area..

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   I’ve done the same process as knuckleharley—put the hot lead from a good battery to the post, and the other lead from the battery to the case. If it spins, it’s good. I also do the same procedure when checking solenoids to make sure it “kicks”. This is especially done “back in the day”, when I used Chevy solenoids in doors as openers when the outside handles were removed.

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Well I have it back together. The rebuilt Kit Andy B. Sells has Bronze Bushings, Washers Leather Washer, Brushes (4), Brush Spring Clips (4), and thats all I can recall.

I even Painted the Tag Red with a Sable Brush, then waited 5 minutes and took Thinner on a Rag and Burnished the Raised Parts to bring back the silver Letters etc.

I have yet to remove my 6 Volt Battery and Test it, using the Knuckleharley method.

20170621_185833.jpg

20170621_192641.jpg

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Looks good,but if it had been me,I would have tested it before I painted it.

 

BTW,you can test it with a 12 volt battery. Won't hurt a thing as long as you don't keep it connected long enough for it to get hot.

It will spin up some serious RPM's with 12 volts.

Edited by knuckleharley
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Results of the Knuckleharley Test - nothing. I am dumbfounded. I have read the Points have to be adjusted within Limits in the Selenoid. But I do not see why it would not be spinning other than the Selenoid is not working. Crap. I now have about $200 in this project with zero results. Any Ideas from the Pros? I have a friend here in NC that may have a spare Selenoid, I will call him tonight. Feeling like Mr. Bad Wrench right about right now.

Tom

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Does the solenoid make any click sound?

Negative (-) Battery cable hooked to the large stud opposite the inner strap stud?..........Positive (+) cable to case ground...

And you are grounding the top inner small stud then hot wiring the top outer small stud?

Have you directly powered the starter motor by passing the solenoid to see that the starter motor itself runs?

 

 

 

 

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16 minutes ago, Tom Skinner said:

I did hook Neg (-) Battery Cable to the Large Stud opposite the Inner Strap Stud..... and The Positive (+) Cable to the Case Ground. Nothing.

How do I directly power the starter motor by passing the selenoid?

My mistake...negative cable goes to the inner stud with the strap to directly power the starter... just to test the starter portion.

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Dodgeb4ya,

With Negative Cable going to Inner Stud with Strap to directly power the Starter - for the Starter portion only. Sparks flew everywhere. Note had I left it this way I would have shorted my Battery. I re-examined my soldered Brushes. everything is in order inside the starter. I tried the other post again as before nothing. No sound out of the Selenoid with a host of hook ups.

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Remove  the copper  strap from the starter stud to solenoid stud and once again connect the positive ground cable to the starter case...

Then the negative cable to a nut on the starter motor stud... starter should spin up to bout 4300 RPM.

All this just to be sure the starter works by passing the solenoid...then on to the solenoid issue.

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5 minutes ago, Tom Skinner said:

OK, now I am getting somewhere. The Sparks fly when I remove the Strap and hook the Neg to the nut and the Positive to the Pinion Housing. Something is wrong in the Starter itself?

Sounds like it. Did you replace the field coils also,or just the brushes and bushings?

Sounds to me like it  is grounding out.

BTW,PLEASE tell me you didn't wire wheel the armature to clean it up.

 

 

Edited by knuckleharley
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