Delco starter overhaul.


Just keep it clean please....

Golden Jubilee
Golden Jubilee

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Location: Lyman, IA

Post Thu Dec 08, 2022 7:35 pm

Delco starter overhaul.

I had a starter "rebuilt" by a company that was known and recommended. The starter never really worked well. Since the truck mostly sits, it was not a pressing problem.
I don't generally do electric motor overhaul as I don't own a growler or armature lathe. At one time I had access to these but it was long ago. So I send them out. I don't send out alternators, I do those myself.
In the last few days it wouldn't crank, so I found another starter on the net and have it coming.
I pulled the defective unit and opened it up. The rebuild was complete trash. The cut the commutator right into where the windings attach, then tried to solder repair the joint! The bushings in both ends were worn beyond serviceable but not replaced. This caused the armature to rub on the pole shoes. To top it off, one of the brushes was put at an angle and only making 1/3rd contact, reducing the current to the armature.
So, I bought a new drive end bushing, a NOS rear cover and bushing, a new set of brushes and debated between a NOS armature and a new aftermarket one, and in the end went with aftermarket at 1/3rd the cost of NOS.
Even if I bought the NOS armature (a little over $100), the total cost is about the same as a rebuilt that was junk.
My advice, for what it is worth, rebuild your own, forget cutting and undercutting armature, just replace it! NOS and aftermarket replacements are available because most of the older starters shared a lot of common parts. Armatures for my K-7 unit were used in GM products, tractors and other makes. The bushings and brushes are still in use
I just looked up the part numbers, both IHC and Delco, and found everything is available NOS and some are in the aftermarket.
The rear cover/brush holder assembly I am getting is still sealed in a Delco box, likely 70 years old.
The skill in motor rebuild comes in evaluating and repairing the commutator/armature, the rest is simple disassembly and re assembly, easy for anyone and just takes common hand tools. Most can judge if a bushing has slop, and can change it if it does.
Given that, I makes even less sense that a paid shop could screw it up that badly!

Rusty Driver
Rusty Driver

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Post Fri Dec 09, 2022 11:57 am

Re: Delco starter overhaul.

Good advice and you don't have to take it apart to see what they've done to it.

Golden Jubilee
Golden Jubilee

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Joined: Thu Nov 29, 2012 9:28 pm

Location: Lyman, IA

Post Fri Dec 09, 2022 12:50 pm

Re: Delco starter overhaul.

You can spend well over $500 for the tooling to service armatures, or you can just replace it if suspect. Depending on how many starters you do, you will likely be better off just buying a new armature.
I don't know how many others do, but for me it is one or two in a decade, that need armature work.
You might be pleasantly surprised by what is available for these old Delco stuff.

Golden Jubilee
Golden Jubilee

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Joined: Thu Nov 29, 2012 9:28 pm

Location: Lyman, IA

Post Mon Dec 12, 2022 3:56 pm

Re: Delco starter overhaul.

Replacement parts are starting to trickle in. Got the armature and brushes, really waiting for the bushings and reamer to size the bushing to finish the starter. I have another used? rebuilt? starter coming tomorrow in case this one doesn't pan out for some reason.
Initial impression of the aftermarket armature is: If I had it to do over again, I'd go with OEM NOS at 2 1/2 times the price. Nothing I can really point to and say it is bad, just the overall appearance and machining is not up to Delco standard, three guesses as to the "country of origin.
If it works and holds up, the appearance will not matter.
The CE frame doesn't use a bushing, steel on steel with an oil wick. I think I'll save the old frame, ream oversize (5/8") and install a DE bushing in that location also.
Tomorrow is supposed to be a "wash-out" rain all day, so I hope I can get one together and in today.
edit: steel on steel in the CE frame really points home the need to keep the "oil cup" on the back of the starter serviced at all times. With the steel shaft riding in the cast iron frame, lubrication is paramount.
The DE has an oilite bushing that holds some lube in the bushing itself.

Golden Jubilee
Golden Jubilee

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Location: Lyman, IA

Post Mon Dec 12, 2022 6:33 pm

Re: Delco starter overhaul.

Got the parts, got the bushing installed, only to find the reamer in the 9/16" box was 7/16"! Not going to happen today.

Golden Jubilee
Golden Jubilee

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Post Wed Dec 14, 2022 8:05 pm

Re: Delco starter overhaul.

Replacement starter came but I need to go through it. Putting a battery on it, it didn't spin. I swapped the nose off the new starter with a good DE bushing, onto the one I was rebuilding. End result is the truck starts better than it ever has. 4 ought cable may have something to do with that.
I will go though the starter that came and put it on my other truck.
So far the aftermarket armature seams to be fine.

Golden Jubilee
Golden Jubilee

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Post Sun Dec 18, 2022 4:58 pm

Re: Delco starter overhaul.

A week or so later:
Starter I bought had several problems, the worse one being the solder joint between the input stud and the field coils. It was hard to find because it would Ohm out ok, but wouldn't carry high current. Long and short it is done and also works. SO that is two starters down.
It was 3 deg F this AM it has warmed into the low 20's and the '42 hasn't been run in a week. Cranked on its own and fired off just fine. I don't remember how old the battery is but at least 5 years I think. Not bad for the old gal.
I have a pair of starters to give away, see the classified section for details. One is a rather rare gear reduction starter for the FBC engines. It is a core and needs work.
I'm getting fairly good at these old Delco's.

Golden Jubilee
Golden Jubilee

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Location: Custer, Washington

Post Mon Dec 19, 2022 9:49 am

Re: Delco starter overhaul.

I have the starter out of my K1 and I tore it apart. Everything looks really good including the brushes. Is there a given set of steps you take with a meter to test the armature and fields out? I have watched a few videos and most are very similar but wanted to know if there a more thorough top to bottom check?

It ends up that this starter used to work fine but I had not tinkered with the truck in awhile. The last thing I did is put the front rubber engine mount piece in. I did not think about the fact that I think I disrupted the ground. The ground from the batter is going directly to the frame but the ground from the frame to the engine I believe was the strap at that front mount. Did a lot of reading on the benefits of having the main battery ground go to the starter due to the huge current load it requires. What are your thoughts on that? I think I may have seen a few comments from you in an older thread. Was also reading some other forums about 6v systems and grounding issues.

I would still like to go through the tests on the starter since I have it out if you have any tips.

Thanks

Golden Jubilee
Golden Jubilee

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Joined: Thu Nov 29, 2012 9:28 pm

Location: Lyman, IA

Post Mon Dec 19, 2022 1:32 pm

Re: Delco starter overhaul.

I am one if not the 1st one, to recommend running the battery direct to the starter/engine and then grounding the frame and body from there.
It is hard to check a starter with an Ohm meter because the resistance of the coils are all less than 1 ohm.
You can check the armature/commutator for shorts to ground, each bar must be infinite Ohms between the bars and the armature shaft.
There are mica separators between the bars on the armature. They must not come up to the surface the brushes ride on. As the commutator wears, the copper bars wear and/or are turned on a lathe to true up. Once that is done, the mica is "under cut" with a thin blade to about 1/8"-1/16" below the level of the bars.
The correct way to check a armature is on a devise called a growler. If you don't have that, it is hard to check out an armature.
The field coils can be checked be checked for continuity and for shorts to ground. power enters at a contact or stud, on the inside of the motor, it splits into two paths, each path go though a det of two field coils (four field coils in all) a north and south coil on each leg. The brushes are in the "outlet" of the field coils. In other words the armature and brushes are in series with each leg of the field.
When you take the brush band off the motor, you can separate the field coils from the brushes The brush wires are screwed to the end of the field coil. Once the brushes are separated, the through bolts can be removed and the rear cover with the brushes can slide off the commutator. WHen that happens they will snap in (springloaded) and you will have to hold them out to re install.
WHen the brushes and rear cover are off you can look over the brushes and brush holder. The "hot" brush holders are insulated from the motor case. The earth brush holders are grounded to the case.
When the through bolts are removed, the starter will come apart in to is component parts. The rear cover, with the brushes and rear bearing and thrust washer, the main case with the field coils and pole shoes, the nose cone and front shaft bushing and the armature, which will come out toward the front or drive end, it will not come out the brush end. (edit: should say the main case will come off the brush end, not the armature. You can't install the armature in the brushes and slip the main case down over it. Don't know why my mind muddled that up).
The three external pieces go together in only one orientation, there are locating pins in the mating faces The through bolts must not come in contact with the field windings or the wires from the brushes.
There are thrust washers on both ends of the commutator shaft, At leat one on each end are a close fit to the shaft while others are a looser fit. Take note of what order and placement on the shaft when you disassemble and put them back in the same order.
This is a lot to try and explain in words. over the .net. If what you want to know is: Is the starter motor good? The easy way is to hook to a battery and make sure it spins when energized. If it does that, don't disassemble but lube the front bushing with light machine oil, and fill the oil cup at the rear. If there is a lot of play in the nose cone, remove the through bolts and slide the nose cone off, but leave the main body and the rear cover together, and replace the nose bushing.
The rear of the armature rides directly cast iron rear cover. For this reason the oil cup and oil wick inside is the only source of lube for the shaft. If it is dry it will drag, and wear the shaft and housing. In my view neglecting to keep it full of oil is the source of much of the problems.
WHen doing the spin test, the motor should kick hard when power is applied, if it doesn't almost kicj out of your hand, then there are problems. There are many internal problems that can happen, but it is hard to walk you through all the test.
That being said. The same armatures were used in a lot of starters and is available NOS or aftermarket. The Aftermarket are cheap enough, that if your armature needs work just buy a $45 replacement armature and change it.
Last edited by cornbinder89 on Fri Dec 30, 2022 10:53 am, edited 1 time in total.

Golden Jubilee
Golden Jubilee

Posts: 432

Joined: Thu Jul 25, 2013 4:16 pm

Location: Custer, Washington

Post Mon Dec 19, 2022 3:34 pm

Re: Delco starter overhaul.

Thanks Cornbinder for all that information. Also of what you explained is what I had read as far as testing dead open or shorts and opens. I also saw a 180 degree ohms test as well on the armature. I did the battery test and it does kick pretty hard. It looks honestly like someone had gone through this starter and then not run it much after that. It came with a GRD 233 I got that had been rebuilt so they may have went through the starter at the same time. Like I said I kind of kick myself for not tying the front rubber engine mount install and the starter not engaging very well after that. I am usually more aware of things like that. Makes sense to run the ground directly to the starter and if not at least to the trans or engine and then have the ground straps going to the frame be there to support the smaller accessories.

I do have a question though. How much end play should the armature have with both end caps on and everything tight? Mine has one single thrust washer but it seems like the armature has a little more end play than you would think it should have but could be fine. So i did read that just light oil on the end caps and like you said the one end has an oiler. Do you oil or grease the shaft and drive gear at all? I know lightly would probably not hurt but just wanted to know what others think.

What size wires do like to run? 2/0 good? I had a negative to starter cable made but just kept the original positive to frame strap. I think Jacob says if you are going to the lower starter bolt the negative should be 36". That is on a KB series. Sure be nice if they made a double threaded bolt/stud if that makes sense. The bolts have a 3/4" head so they are pretty large bolts. 1/2" or bigger I think. I need to measure.

Thanks Again for your help. I know you and I do not agree politically but it is nice to know we can still help each other.

Take Care.
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