10MT Starters keep working too long

Matt Colie

Well-known member
Aug 15, 2008
11,101
807
113
South East Michigan near DTW
I wrote a bit about this once before, but I think it merits another and more complete post.

Executive summary: If you are going into the hinterlands and are not carrying a spare starter, think about it.

The 10MT starter that the 425 uses is a brute. It is also the only essential small part for which there is no "work around".

The big issue you should be aware of (and I am now) is that they will keep turning a 455 long after they should have packed up and gone home.

I had what I believed was a bad connection to the main engine battery. That is exactly the way it was behaving. Then it stopped. A tap got just one
more crank. When I was a ship's electrician (before licensing), I did a lot with big old DC motors. So, I blocked up the coach enough to get over
the tire and get the starter out. "I can probably make it work again." (He says to hisself). There on the dirt of the fairground. I undid the three
essential fasteners and popped the back plate off. My only option then was to say "Good Lord" and put the plate back on. There was not any mount of
jury rig that was going to make that happen.

This was Sunday afternoon in Evart Michigan (the Dulcimer Festival).
Do you know what Evart Michigan is near??? NOTHING (It is about half way between Midland and Ludingon and as far north of Mt. Pleasant.

I started working the phone. The local parts store is closed on Sunday, the next nearest (40 miles) thought that they could have one Monday. (Mary
had to be back at work by then.) I kept calling in ever widening circles and even the NAPA wearhouse (closer to home that Evart) said that they could
not have one for three days.

There were two on the Black List that could not help, then Don Hart (about 100 miles away) said he could have one off a parts coach and bring it to
me. (This is the community at our side again.) He did, would not even take gas money and stayed by until I got the coach started. I got him a fresh
rebuild with a lifetime warranty.

Ours is unique in the Delco line only for the nose casting. Yes, they can be rebuilt, and I have now done a few. The synopsis of the problem is that
the bushes can wear until they are GONE. When that happens, there is no simple way to recover. At that time, parts have to be replaced.

So, we have a 23' coach with no pod. I carry a starter in the spares locker. The only heavy spare I carry.

Matt

--
Matt & Mary Colie - '73 Glacier 23 - Members GMCMI, GMCGL, GMCES
Electronically Controlled Quiet Engine Cooling Fan
OE Rear Drum Brakes with Applied Control Arms
SE Michigan - Twixt A2 and Detroit
 
I collected cores for a long time until I had a 1/2 dozen good ones with a
bunch of spare pieces. I took 6 to my local rebuilder, and had 3 standard
duty done, and 3 high torque. So, if someone has a giant killer high
compression engine, I have a starter that will spin it, in stock.
I usually have alternators in stock also, but currently am out. I
have some good cores, before too long, i will wander down to my rebuilder
and have him fix them up. Handy stuff to have on hand for those Sunday
phone calls.
Jim Hupy
Salem, Or

> I wrote a bit about this once before, but I think it merits another and
> more complete post.
>
> Executive summary: If you are going into the hinterlands and are not
> carrying a spare starter, think about it.
>
> The 10MT starter that the 425 uses is a brute. It is also the only
> essential small part for which there is no "work around".
>
> The big issue you should be aware of (and I am now) is that they will keep
> turning a 455 long after they should have packed up and gone home.
>
> I had what I believed was a bad connection to the main engine battery.
> That is exactly the way it was behaving. Then it stopped. A tap got just
> one
> more crank. When I was a ship's electrician (before licensing), I did a
> lot with big old DC motors. So, I blocked up the coach enough to get over
> the tire and get the starter out. "I can probably make it work again."
> (He says to hisself). There on the dirt of the fairground. I undid the
> three
> essential fasteners and popped the back plate off. My only option then
> was to say "Good Lord" and put the plate back on. There was not any mount
> of
> jury rig that was going to make that happen.
>
> This was Sunday afternoon in Evart Michigan (the Dulcimer Festival).
> Do you know what Evart Michigan is near??? NOTHING (It is about half
> way between Midland and Ludingon and as far north of Mt. Pleasant.
>
> I started working the phone. The local parts store is closed on Sunday,
> the next nearest (40 miles) thought that they could have one Monday. (Mary
> had to be back at work by then.) I kept calling in ever widening circles
> and even the NAPA wearhouse (closer to home that Evart) said that they could
> not have one for three days.
>
> There were two on the Black List that could not help, then Don Hart (about
> 100 miles away) said he could have one off a parts coach and bring it to
> me. (This is the community at our side again.) He did, would not even
> take gas money and stayed by until I got the coach started. I got him a
> fresh
> rebuild with a lifetime warranty.
>
> Ours is unique in the Delco line only for the nose casting. Yes, they can
> be rebuilt, and I have now done a few. The synopsis of the problem is that
> the bushes can wear until they are GONE. When that happens, there is no
> simple way to recover. At that time, parts have to be replaced.
>
> So, we have a 23' coach with no pod. I carry a starter in the spares
> locker. The only heavy spare I carry.
>
> Matt
>
> --
> Matt & Mary Colie - '73 Glacier 23 - Members GMCMI, GMCGL, GMCES
> Electronically Controlled Quiet Engine Cooling Fan
> OE Rear Drum Brakes with Applied Control Arms
> SE Michigan - Twixt A2 and Detroit
>
> _______________________________________________
> GMCnet mailing list
> Unsubscribe or Change List Options:
> http://list.gmcnet.org/mailman/listinfo/gmclist_list.gmcnet.org
>
 
Matt, If I remember right, didn't you do a presentation at one of the ES rallies, maybe at Milan, on the rebuilding of the starter motor? If you did,
is that published anywhere? Might help some of the newbies and maybe refresh some of us other owners...
Thanks,
Shot
--
John Shotwell
Ridgeville Corners, OH
78 Royale Center Kitchen
Web Site: GMCmhRegistry.com
Email: john at gmcmhregistry dot com
 
> Matt, If I remember right, didn't you do a presentation at one of the ES rallies, maybe at Milan, on the rebuilding of the starter motor? If you
> did, is that published anywhere? Might help some of the newbies and maybe refresh some of us other owners...
> Thanks,
> Shot
> or maybe it was just the solenoid???

John,

It was the whole starter..

I have done that show a couple of times and still have it in my files. I gave a few people copies and I though it got posted somewhere, but right off
hand, I don't know where it might be.

When I come up for air (when the Chaumière comes out of the barn), maybe I will pursue making sure it is posted somewhere.

Matt

--
Matt & Mary Colie - '73 Glacier 23 - Members GMCMI, GMCGL, GMCES
Electronically Controlled Quiet Engine Cooling Fan
OE Rear Drum Brakes with Applied Control Arms
SE Michigan - Twixt A2 and Detroit
 
> Executive summary: If you are going into the hinterlands and are not carrying a spare starter, think about it.
>
> ....
>
> So, we have a 23' coach with no pod. I carry a starter in the spares locker. The only heavy spare I carry.
>
> Matt

Matt,
I also carry a spare starter because as you suggest there is no work around if it quits. Even if there is an auto parts store close by with a
starter, it might be a long walk to and from since we don't currently have a towed. I suppose we could try to hire an Uber but I'd rather do the R&R
on site (camp ground etc.) and be on our way. Replacing a starter is pretty simple on these beasts if you have one. My spare is a known good one. It
lives in our pod along with a spare air compressor and a complete computer controlled HEI distributor. The smaller spares (fuel pump, modules etc.)
occupy space inside.

--
Richard
76 Palm Beach
SE Michigan
www.PalmBeachGMC.com


Coop Roller Cam 455, Howell TBI + EBL, 3.42 FD, Quadra Bag, Macerator, Manny Tranny etc.
 
Read here

http://www.gmcmhphotos.com/photos/gmc-cranking-improve-for-free/p34367-hot-start-problem-2c-battery-2f-starter.html

> > Executive summary: If you are going into the hinterlands and are not
> carrying a spare starter, think about it.
> >
> > ....
> >
> > So, we have a 23' coach with no pod. I carry a starter in the spares
> locker. The only heavy spare I carry.
> >
> > Matt
>
> Matt,
> I also carry a spare starter because as you suggest there is no work
> around if it quits. Even if there is an auto parts store close by with a
> starter, it might be a long walk to and from since we don't currently have
> a towed. I suppose we could try to hire an Uber but I'd rather do the R&R
> on site (camp ground etc.) and be on our way. Replacing a starter is
> pretty simple on these beasts if you have one. My spare is a known good
> one. It
> lives in our pod along with a spare air compressor and a complete computer
> controlled HEI distributor. The smaller spares (fuel pump, modules etc.)
> occupy space inside.
>
>
> --
> Richard
> 76 Palm Beach
> SE Michigan
> www.PalmBeachGMC.com
>
>
> Coop Roller Cam 455, Howell TBI + EBL, 3.42 FD, Quadra Bag, Macerator,
> Manny Tranny etc.
>
>
> _______________________________________________
> GMCnet mailing list
> Unsubscribe or Change List Options:
> http://list.gmcnet.org/mailman/listinfo/gmclist_list.gmcnet.org
>
--
Gene Fisher -- 74-23,77PB/ore/ca
“Give a man a fish; you have fed him for today --- give him a URL and
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