Starter motor

[Jens]

A weird issue is cropping up with my 12V electric starter which I am running at 24V. I crank the engine over, the starter releases as I stop cranking but the motor doesn't stop right away. It spins way up in speed (sounds like a jet engine winding up) and then eventually, after maybe 10 to 20 seconds, it slows and stops. Sort of as if the internal contacts that engage when the solenoid brings the drive gear out toward the ring gear is getting stuck.
Anybody ever encounter that ? Is this a precursor of a starter failure ?

FWIW, the solenoid is operated by 12V but the starter motor itself runs on 24V even though it is only a 12V starter.

[mobile_bob]

if the 12volt switch circuit is cutting off as designed the only other possibility is the solenoid contacts are sticking
and yes this is a common problem with starters that are asked to do things they were not meant to do.

in other words the current draw can be high and cause issues, or the voltage low, or i suppose possibly voltage high
to the starter.

was the starter a new one to start with?

you need to address this problem asap, the reason being the motor will overspeed on 24 volts (jet motor sound) and increase
the likelihood that it will thrown out windings from the armature of even commutator bars, basically a catastrophic failure.

we see stuck solenoids keeping the starters engaged on heavy truck with some regularity, usually in the winter months when the e
batteries are tired and the engine is very cold, the voltage dips low and the amps go way up which causes the conatacts in the solenoid to weld themselves together enough that they cannot release.

usually a couple of sharp blows to the starter body with a hammer will usually cause the contacts to break lose and the starter will then quit cranking a running engine, then we get a call and we go replace the starter because if it happens once it will happen again, and if the thing is allowed to stay engaged while they drive the truck then the starter gets it guts spun out of it and its toast
anyway.

bob g

[Crofter]

Jens, If that is a Delco Remy, I have seen a similar problem though it may not be in your case. There is a very light coil spring that opposes the contact disc. The plunger overcomes it in the process of making contact but it is entirely up to that little spring to part the contacts as the plunger withdraws. Occasionally they get left out if someone has had them apart. Barring that it may be as Bob says that the contacts are fusing a bit with the heavy current.

[Rob Windt]

May or may not be relevant but - Hopped up flatheads with 6v starters would be OK if engaged with 6v by the key start and then hit with 12v by a relayed push button while winding - it stopped them from banging themselves to death
Your mileage may vary
Rob
http://nakedmechanic.blogspot.com/

[Ronmar]

Had this happen in an old datsun I used to own way back when.  Cooked off a starter at a gas station, as it took me several minutes to get under the hood and get a battery terminal off.  It dosn't take many high speed/overspeed runs to severely damage the motor bearings and commutator...  I replaced the solenoid contactor on that starter, but the starter motor eventually siezed about 3 weeks later...  It was a mess when I completely disassembled it.

[Crofter]

Jens, you are starting to seem like the Hee Haw character that sang "if it weren't for bad luck, I'd have no luck at all"

When I picked up my starter and ring gear at the wrecking yard the fellow just said if its GM they are all the same teeth but that could be bunk. Are the non gear reduction starters cheaper and the same mount? I didnt know they now had the solenoids crimped together but it figures.

Occasionally a bearing will have the plastic ball cage disintegrate and the failure then is instant. Maybe sometimes one could happen to miss being greased in the process too I suppose.

[mobile_bob]

the gm drives are all the same pitch, however there are different sizes of flexplate/flywheel with more or less tooth counts

i think ford is the same within it product line, likely the same for chrysler products

save for the rebadged import car's which have any number of countries of origin

bob g

[AdeV]

I have a Ford starter meshed to my GM flex plate. An Austin Rover starter would have worked as well, had it turned the right way.

I think the ring gears are probably pretty standard the world over; of course, the location & size of the fitting bolts, well, open season on that one...

[Crofter]

That is a cute little starter Jens. The different size ring gears may be for the V8 VS the 4Cyls so should make no difference to the drive gear on the starter. You may be able to go back to 12 V and still be able to crank up without decompressor. I have the ring gear turning at motor speed (not at gen speed) and can get through with a grunt then off to the races so you should have no trouble getting through geared down from the gen. as long as belt doesnt slip.

[vdubnut62]

Jens there is a starter guy here in Cookeville TN. that sells the gear reduction starter for $79. He says it is a late model Chevy 454
cu in V-8 starter. He rebuilds and sells parts for them too. I'm pretty sure that with our sales tax - 9.75%  and shipping to the
Great White North you would be on the losing end on a complete starter, but I might be able to help you out on a bearing,
how does around $5 plus tax and shipping sound?
Ron

[AdeV]

Have you considered just using a normal starter? One from any older diesel motor should have plenty of torque to pull your engine around fast enough to light it off.

[bschwartz]

Would this 'up north' ebay unit work?

http://cgi.ebay.com/ebaymotors/chev-race-car-gear-reduction-starter-small-big-block-_W0QQcmdZViewItemQQhashZitem3363544db1QQitemZ220709801393QQptZMotorsQ5fCarQ5fTruckQ5fPartsQ5fAccessories#ht_500wt_958

......... I like finding stuff.......... 

[vdubnut62]

I think I would go with the new starter meself! You really need to stay away from 24 volts IF you can.
That's 2X the stress that starter was designed for.
Best of luck.
Ron

[SteveU.]

Hi Jens
I worked exclusively in the auto electric field for 16 years. As an interest I built up high torque/high horse power starters for high compression hot rods and diesel vehicle conversion units: e.g. a 6 cylinder Perkins in an auto trans Ford commutor van back in the fuel starved early 70's. Life and wear on the then standard sized Ford, GM and Chrysler units even with carefull hand selected parts matching was only at best 20-30% of normal (or the first 3+ minutes of contious overheating cranking). Thats hot-rodding.

Juicing any 12 volt based unit with 24 volts tends to mechanically break things internally due to the now slamming/hammering actuation. Drive teeth, drive overrunning clutch, shift forks, retainer/stop collars, etc, etc.

The Hitatchi GR unit you have pictured have VERY weak plastic based shift forks and/or pivot pieces - wanna bet it is broken/worn?

As AdeV said you would be much better off with one of the longer, heavier earlier 20MT (two pole shoe screws per pole) 12 volt direct drive GM Delco units OR one of the later, best in the world, hell for stout Nippon Denso based gear reduction units. These do both have replaceable round plate solenoid contacts and studs. The Hitatchi, Mitsubushi and Bosch units all have roll crimped sealed cap solenoids without the wear distributing round contact feature. Hot spot the same connecting place every time rectangular contacts in these brand/designs and then have to replace a whole new throw-a-way solenoid assembly.
Regards
SteveU.

[vdubnut62]

I just happen to have one of the Denso units off a 91 Cummins 5.9 also just happen to have the flex plate to match
And I have replaced the contacts in the starter solenoid off my pickup. My starter guy has them in stock. (same starter but different year = different bolt pattern) Only thing that's a problem is the brushes are welded in, but you can oxy acetylene
braze or spot weld new ones in.
Ron