Starter on 8BA won't turn when HOT. What gives?

[Flathead Guy]

I have a recently acquired '48 Coupe with a '50 8BA installed. When the starter (and engine) are cold, the starter cranks no problem. But when I try to start it when its hot, the starter is practically seized. I let it sit for 10-15 minutes and it cranks without issue. It's got a brand new 6 volt battery, new cables.

Do I need to place shims between the starter and motor? Or is the Starter bushings/bearings too tight?
Suggestions appreciated.

[flatheadmurre]

No need for shims...
If you don´t know your way around a starter bring it to a starter shop....also bring the solenoid.

[41ford1]

Starter bushings/bearings may be worn out. That causes the armature to drag on the fields when hot. I'll second flatheadmurre, take it to a good electric motor rebuild shop.

[joe 1950]

you say it has new cables but what size wire the small 12 volt cables don’t work good on these old 6 volt systems but as 41ford said bushings are a big problem i worked for a cadillac dealer for 20 years we rebuilt all starters and generators and when those big caddy motors where hot they won’t turn over with a bad starter.

[Flathead Guy]

Thanks guys for the quick responses! I wanted to make sure I wasn't missing something simple. I'll pull it out and go thru it. I'll double check the battery cable size, but I recall it being very thick gauge.

[19Fordy]

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Here's an informative thread.
https://www.fordbarn.com/forum/showt...racket+oil+pan

[Kurt in NJ]

crank for 15 seconds with ignition off ----then feel all wires and connections, if you get burned look there
when you put the cables on what condition were the nuts and washers ---the power coming out a stud has to conduct through the threads to the sides of the nut, through the washer---i have fixed many problems with new nuts and washers

worn bushings---loose field pole pieces can cause armature dragging

many of the pre made cables have steel terminals that don't connect to the wire well, I use copper/brass terminal ends crimped and soldered

another thing I have found is that the solder connections between the windings and commutator can fatigue

[Thomas911-76]

Originally Posted by Flathead Guy

I have a recently acquired '48 Coupe with a '50 8BA installed. When the starter (and engine) are cold, the starter cranks no problem. But when I try to start it when its hot, the starter is practically seized. I let it sit for 10-15 minutes and it cranks without issue. It's got a brand new 6 volt battery, new cables.

Do I need to place shims between the starter and motor? Or is the Starter bushings/bearings too tight?
Suggestions appreciated.

One year ago I had the same problem with my starter. I renew all cables and connections. But the same problem. The cables getting hot when try to start a few seconds. But the starter turned only very slow when motor is hot.
After this I checked the starter him selve.
There was bad oxidation between the aluminum head and the iron body. Also the two long bolts through the starter. So the starter have had bad ground problems.
After cleaning everything the starter runs as new.
Maybe this is also your problem?
Sorry for my bad English. I am from Germany [emoji16].

Gesendet von meinem ANE-LX1 mit Tapatalk

[PeteVS]

Resistance to current flow increases when the conductor is heated. The starter is mounted on the engine and engine heat causes the starter to be warmed. I'd say this is a portion of your problem. There might also be a mechanical problem causing binding. Look for dry bushings or worn bushings allowing the armature to drag on the field poles.

[JM 35 Sedan]

Originally Posted by Flathead Guy

I have a recently acquired '48 Coupe with a '50 8BA installed. When the starter (and engine) are cold, the starter cranks no problem. But when I try to start it when its hot, the starter is practically seized. I let it sit for 10-15 minutes and it cranks without issue. It's got a brand new 6 volt battery, new cables.

Do I need to place shims between the starter and motor? Or is the Starter bushings/bearings too tight?
Suggestions appreciated.

All great ideas have been given here! Check each one carefully and make sure ALL electrical connections in your starting system have a "bright and shinny" interface, including any of the hardware used in making those connections.
I once had a similar problem as yours, so, I bought my first Optima 6V Red Top battery, thinking those extra cranking amps would be the "fix"....it was slightly better, but still not what I was hoping for.....so, I cleaned every electrical connection, including the interface of many components critical for good current flow, and after doing all of that, the standard 6V system spun the engine as if it was a fully charged 12V system.

[1931 flamingo]

I had similar problems on a 59AB in my 40. Found that the NEW starter's armature was not concentric to the armature shaft. Re-installed the original starter after having it checked out, cleaned all the connections and now spins nicely. FWIW
Paul in CT


KUDO's to Ronnie Roadster for finding this.

[Floyd]

Starter bushings never get the fame or attention that they deserve. Although starter brushes almost never wear out, bushings always do. This is a classic case of an "electrical" problem being mechanical in nature. The rear bushing is pressed into a blind cavity and difficult to remove, tap, thread and pull is best method. Also NOS rear endplates are available and the best deal. You get the plate, brush springs and correct bushing. The front one is easier as it can be pulled, pushed or cut out.
A starter without new bushings is NOT a rebuilt or even a repaired starter. Try it, you will be amazed. Of course armatures, field windings and shaft must be checked also.
My opinion and experience

[tubman]

I bought a couple of dozen flathead starter bushings from Rock Auto a while ago for next to nothing. The probably still have a bunch left.

[Kerk]

I am a firm believer in checking all groung connctions. The one that gets overlooked many times is the Mounting surfaces Remove and clean up the surface on the pan and the end plate of the starter and reinstall after checking the starter out completely. Kerk

[Old Redneck]

I bought a 38 coupe that had the same problem. Check that the plug wires are on correct. I had two cross. It ran ok but a lot more smooth when corected.

[JM 35 Sedan]

Reference similar post with same basic problem...click on URL below for additional information on same basic subject....

https://www.fordbarn.com/forum/showthread.php?t=244430

[Flathead Guy]

I solved this issue by cleaning the contacts on the two heavy gauge Starter wires on the Starter Solenoid among other things.

I put a video of it on my YouTube Channel that shows more details of the whole adventure!


Here's the link--> https://youtu.be/p0qgVhu8wGc


Thanks for everyone's replies!

[Mart]

Good video Terry. I also watched the Model a kingpin one and subbed ya.

Mart.

[Black Fifty]

Nice little video, Terry.

I liked that you included the first attempt after reinstalling the cleaned up starter. All of us know that feeling when you're sure you have it licked and then it does the same damn thing.

Glad that you got her running. I see you have the rare air conditioned model.

Mike

[PeteVS]

Another way of checking out your connections is to connect a volt meter to the "hot" post of the battery, preferably on the battery post itself, not the clamp. Then, while someone cranks the engine, check the voltage at the battery clamp, the cable at the clamp, the post on the solenoid, the other post on the solenoid and finally the post on the starter. There shouldn't be more than 2 or so volts showing at any point along the line. With the engine being cranked, also check the opposite battery post. That shouldn't drop appreciably. Repeat the operation on the ground side from the battery post through all the connections to the end plate of the starter.