Starter too hot to touch!

[1970stringbean]

We've been having some electrical issues. PO had hacked the ignition circuit beyond recognition. Got that straightened out. Drove the truck (1970 K10) for the 1st time today, since engine rebuild. Got to work shut it off, went back out 30 minutes later and nothing. Crawled under it to make sure a wire hadn't come loose. The starter was so hot it actually burnt my hand! Luckily, I had another starter, swapped it out and made it home tonight. What in the world would have caused this? I am at a loss here, any advice would be greatly appreciated!

[VetteVet]

Originally Posted by 1970stringbean

We've been having some electrical issues. PO had hacked the ignition circuit beyond recognition. Got that straightened out. Drove the truck (1970 K10) for the 1st time today, since engine rebuild. Got to work shut it off, went back out 30 minutes later and nothing. Crawled under it to make sure a wire hadn't come loose. The starter was so hot it actually burnt my hand! Luckily, I had another starter, swapped it out and made it home tonight. What in the world would have caused this? I am at a loss here, any advice would be greatly appreciated!

Most likely it's heat soak on the solenoid caused by headers too close to the starter. Heat causes excessive resistance to current flow in the solenoid windings so it can't actuate the relay contacts to the starter windings.

You can:

1.clean all your cable connections and grounds.
2.buy a new heavy duty starter
3. buy a mini-torque starter
4. Re-wire the solenoid with a Ford solenoid
5. get a heat shield for the starter-probably too late for yours.

[1970stringbean]

Thanks so much! You really are the electrical guru, aren't you! We have all new cables and wiring going to the solenoid, even ran an extra ground cable from the block to the frame. It has stock exhaust manifolds on it. We did however switch to vortec heads with "towing" cam. Our goal was to build a good dependable daily driver, not a hot rod engine. So far, so good, we still have an oil leak to fix and the valves need adjusting a little more, but other than that, it's running better than it ever has since we've owned it. VV, again, Thank you!

[Dead Parrot]

Could have been simply that starter #1 was EOL and picked that moment to quit. If you have a 195 tstat, the normal operating temps will be around 210. Once you shut it off, the extra heat in those stock exhaust manifolds has to go somewhere and in summer, you won't get much cooling when the air temps are near 100. You can retest the 'too hot starter' by touching the new one 30 minutes after a similar drive. Just have a bucket of cold water handy to cool your hand.

VV's #1 suggestion is always a good first step.

One thing I discovered is that if your brushes are shot, you can sometimes get '1 more start' by tapping the bearing cup on the front facing end of the starter. The bump will sometimes get the worn brushes to contact and let it start.

[franken]

The starter should essentially be at the temperature of the block, since that's what it's bolted to. Did the block burn your fingers too?
The solenoid is not heat soaked if jumping it (same as adding another solenoid) makes it work. The difference is the amount of current the S is allowed to draw can be more due to the length of cable, ignition switch, connectors, and age of cables. All those need to work right and allow the needed current to pass.
The big ground should be from the battery to the block.

But people don't want the troubleshoot--they want the internet to do it for them.

[kyhillbilly]

The cable (wire) going to the S terminal was in bad shape, so we cut it off about 6 inches from the bulkhead and ran a new wire, 10 gauge, if I remember correctly. The extra ground cable that was installed was the same gauge as the cable from the negative post on the battery to the block. We still have some starting issues but they are due to the NSS. It's an automatic and there's a lot of slop in the shifter, so we have to pull up on the shifter handle so it will make contact. We may have damaged the NSS switch, have to get a little rough with it sometimes before it makes contact. Any advice is greatly appreciated. Thanks

[franken]

I think you should start a new thread since this seems to have nothing to do with the original. Replace the NSS and troubleshoot the slop--you seem to have it figured out already...