No Crank / No Start

[Schurkey]

that's crazy I've never seen that in my life

EVERY bigass direct-drive starter on a Chevy had a similar bracket when it left the factory. Since 1955. Lazy mechanics fail to reinstall them when the starter gets replaced.

Every Olds, Buick, Cadillac, Pontiac had a similar-purpose bracket--often bolted to the side of the starter; and most of them are missing now, too.

 

[Road Trip]

Its the old style/ factory bolts/ im not sure of the brace bracket its just two larger bolts and there never was a heat shield

Of course there was a heat shield. Someone took it off, and failed to replace it.

Hello hilly,

I get it. I'll bet the majority of used SBCs that had the starter replaced are missing the original heat shield.
But as Schurkey stated the factory heat shields have been installed since forever. To give you an idea of what's missing I
decided to look up your vehicle at a GM parts site:

You must be registered for see images attach

Googling starter heat shield 10068600 didn't come back with the exact same part being sold, *but*
it does show a lot of aftermarket heat shields available from the usual sources.

But if you are feeling creative, read this thread over in the jalopyjournal website. There's a thread where
hot rodders that were suffering hot start issues shared their home brewed heat shield fixes. It's a good read: (Starter Heat Shields)
NOTE: They also mentioned the benefits of upgrading old classic direct drive starters to the newer GM gear reduction units.

Re: Heat related intermittent no-crank to other components in the Ignition Circuit.

If you peruse the wiring diagrams, Circuit #6 is Hot only when the Ignition Key is in the START position,
and the Neutral Safety Switch is is either in Park or Neutral positions. (Or Clutch Depressed switch is
closed if you are driving a stick.) This circuit is protected by the 5A CRANK fuse.

On the other hand, the ECM / ESC / ICM are on a completely difference circuit (#439) which is fed by the 10A
ECM IGN fuse. (Hot in Start & Run)

In English, the ICM has no direct influence on the CRANK control circuit.

This is why troubleshooters want to know if the symptoms are 'No Crank/No Start' versus 'Crank/No Start'.
This small behavior detail completely changes which electrical circuit gets troubleshot.

One last possible workaround until you can get the heat shield either bought (or fabbed up) and installed.
If you drive your truck long enough that you think that it's going to heat soak the starter solenoid, simply pop
your hood & raise it fully when you first park the vehicle.

This way, instead of the underhood heat building up and causing the heat soak of the solenoid windings, you
instead get cooling air pulled in from underneath due to the chimney effect. May or may not make a difference,
depending upon the variables, but it's worth a try.

Who knows? You may find a heat shield in the treasure yard on a unicorn GMT400 where a detail-oriented
owner kept reinstalling the heat shield.

When you get the fix implemented, be sure to come back and share the solution with others researching
similar symptoms.

Happy Hunting --

 

[hilly101111111]

Hello hilly,

I get it. I'll bet the majority of used SBCs that had the starter replaced are missing the original heat shield.
But as Schurkey stated the factory heat shields have been installed since forever. To give you an idea of what's missing I
decided to look up your vehicle at a GM parts site:

You must be registered for see images attach

Googling starter heat shield 10068600 didn't come back with the exact same part being sold, *but*
it does show a lot of aftermarket heat shields available from the usual sources.

But if you are feeling creative, read this thread over in the jalopyjournal website. There's a thread where
hot rodders that were suffering hot start issues shared their home brewed heat shield fixes. It's a good read: (Starter Heat Shields)
NOTE: They also mentioned the benefits of upgrading old classic direct drive starters to the newer GM gear reduction units.

Re: Heat related intermittent no-crank to other components in the Ignition Circuit.

If you peruse the wiring diagrams, Circuit #6 is Hot only when the Ignition Key is in the START position,
and the Neutral Safety Switch is is either in Park or Neutral positions. (Or Clutch Depressed switch is
closed if you are driving a stick.) This circuit is protected by the 5A CRANK fuse.

On the other hand, the ECM / ESC / ICM are on a completely difference circuit (#439) which is fed by the 10A
ECM IGN fuse. (Hot in Start & Run)

In English, the ICM has no direct influence on the CRANK control circuit.

This is why troubleshooters want to know if the symptoms are 'No Crank/No Start' versus 'Crank/No Start'.
This small behavior detail completely changes which electrical circuit gets troubleshot.

One last possible workaround until you can get the heat shield either bought (or fabbed up) and installed.
If you drive your truck long enough that you think that it's going to heat soak the starter solenoid, simply pop
your hood & raise it fully when you first park the vehicle.

This way, instead of the underhood heat building up and causing the heat soak of the solenoid windings, you
instead get cooling air pulled in from underneath due to the chimney effect. May or may not make a difference,
depending upon the variables, but it's worth a try.

Who knows? You may find a heat shield in the treasure yard on a unicorn GMT400 where a detail-oriented
owner kept reinstalling the heat shield.

When you get the fix implemented, be sure to come back and share the solution with others researching
similar symptoms.

Happy Hunting --

Hey I really appreciate the information ! I managed to order a shield from amazon of all places and its a factory replacement from gm just didn't put it on yet. yeh if you let it sit for 20 min it doesn't do it. !

 

[Schurkey]

I'll bet the majority of used SBCs that had the starter replaced are missing the original heat shield.
But as Schurkey stated the factory heat shields have been installed since forever.

Well...ummm...what I said was that the bracket/brace from the front of the starter to the block has been used for the entire run of direct-drive, bigass starter motors.

Fairly sure the heat shields came along later. But one of the applications for the heat shields was the GMT400 with bigass starter motors.

 

[Road Trip]

Well...ummm...what I said was that the bracket/brace from the front of the starter to the block has been used for the entire run of direct-drive, bigass starter motors.

Apologies if I misquoted you. I do know that the 'struggles/won't start hot' lament was frequently heard
in my social circles back in the day. Of course we were all installing headers and throwing in additional base
timing on the dizzy, so on summer nights the extra-slow whaaa whaaa whaaa fire was frequently heard.
So it just seems that we've been putting on heat shields since forever. :0)

Along these lines, here's a nice photo a SBC with ram's head exhaust manifolds, big direct-drive starter
with front support bracket, all capped off with a retrofit starter heat shield:

You must be registered for see images attach

Nicer than brand new starter installation to improve hot starting on vintage high output SBC.

Fairly sure the heat shields came along later. But one of the applications for the heat shields was the GMT400 with bigass starter motors.

I'm trying to remember the first time I saw a factory heat shield...and alas, since all my buddies & I were
driving well-used vehicles, I can't remember seeing an original, but we certainly added a few where the
owners weren't willing to leave the hood up -or- wait until the engine bay temps dropped. :0)

And on that note, this conversation makes me want to check the chore truck to see if the big block's
starter has a heat shield or not. I haven't had any trouble with the starter while lumbering around
town lightly loaded...but I'd hate to discover that it's missing after building some heat while towing
all my precious possessions to my next abode.

Tip of the hat for making me think some more before towing...

 

[Schurkey]

You must be registered for see images attach

Same heat shield I have on the 'Camino engine. I like metal heat shields rather than fiber/fabric "blankets" because they allow the starter heat to escape while blocking exhaust heat from the starter/solenoid.

Photo from the "Trial Assembly" about a thousand years ago. There have been some changes since then...

You must be registered for see images attach

 

[scott2093]

Well...ummm...what I said was that the bracket/brace from the front of the starter to the block has been used for the entire run of direct-drive, bigass starter motors.

Fairly sure the heat shields came along later. But one of the applications for the heat shields was the GMT400 with bigass starter motors.

I have a heat shield but never knew I may be missing something.. Can definitely see how something would be useful for these too heavy starters..
Jeez...
I'm not seeing anything for my truck