Engine Won't Start when Hot. Help!

[Radiatta_71]

Here is the situation...

Starts fine when cold but after it warms up it acts as though the battery is dead.

'72 blazer 350 with newly installed HEI (although did the same thing with points but only occasionly) headers. Has a new battery, starter, Starter solenoid, plugs, cap and rotor, spark plug wires and a new cable going to the starter from the battery.

I also added a shroud to the starter sol. thinking it was heat related.

Could the timing cause this? I know the timing isn't perfect but I adjusted it a little and no effect on starting.

I am stumped on this... what else would be heat related?

Thanks all!

[chevy72402]

just an idea, but how close do your headers come to your starter? I had a problem with my starter absorbing the heat because the Big block and the exhaust running next to it. I am not sure how to insulate it but it's an idea

[ebbhightower]

I OWN A 71 SHORT BED STEPSIDE WITH A 350 CU IN ENGINE WITH HEADERS AND I THOUGHT IT WAS HEAT SOAK ON THE STARTER FROM THE HEADERS. IT COULD BE A TIMING ISSUE, BUT I ADDED A HEAVY DUTY RELAY ON THE VIOLET STARTER WIRE TO BOOST THE AMPERES COMING FROM THE KEYSWITCH AND IT FIXED MY PROBLEM.HOPE IT WILL HELP. ebbhightower

[Tx Firefighter]

If you think it's timing, do this simple test...

Unplug the 12 volt wire to the HEI and crank it. That removes the ignition from equation. If it still cranks hard, it's not ignition.

[kelsfine69]

If you turn the key and nothing, not even a click, and the headlights, Radio, wipers work then its a heat sink problem. You said you shielded the starter but that might not be enough. I had the same problem for years, just waited for the truck to cool enough to start, but that sucks. I went to a gear reduction Power master starter with zero heat sink. Problem solved forever, worth every penny. i have heard of guys using a GM gear reduction starter but then you get back into a heat sink problem with the solinoid and trying to cover the solenoid with some sort of heat shield only lasts for a while and a PITA. Thought Id share a been there done that.

[72armyswbtruck]

If you switched to HEI, then it probably is the egnition module in the distrubutor (it should have some die electric grease underneath the module that keeps it cool) you can take just this item out without harming timing or the truck (takeit to autozone or local parts store and have it tested) if it;s not good then theres the problem, if not move on to the others.

[shifty]

quick way to find out if it's heat soak on the starter is to get some heat shield wrap (it's cheap) and wrap your starter up with it when its cold. fire up, run till hot and see if it will start after. It's probably the cheapest easiest thing to isolate. Then proceed with the other stuff.

If you're running HEI, sometimes heat will caust it not to operate correctly.

If it won't turn over, I would think it's starter related - either too much heat or not enough power.

YOU *DID* REWIRE THE LINES AFTER INSTALLING HEI, RIGHT? You can't use the original cloth wires used for the coil when you upgrade to HEI.

[Huck]

Chevy's have had a heat related starter problem since their first V8 in 55'. Shielding usually takes care of it. Next time it does it, if home---unhook the battery ground and sprey a hose onto the starter or compressed air to cool it quick. Let it dry just a bit then rehook the battery. If it kicks right over, you know the problem. Many solutions available (shielding, different type starter, remote solenoid).
IF your engine was recently rebuilt or just nice and tight, you may have a grounding problem with the block. As it gets to normal operating temperature, all tollerences close up at the metal swells with the heat. Check the grounds that run from the valve covers to the firewall and the big ground from the battery to the block & radiator support. They all need to be there, clean and tight.
Let us know what you find.

[cdowns]

for electrical problems my first stop is disassembling and cleaning all ground wires // nothing works right without a proper ground and merely looking at them does nothing to assure a proper electrical circuit// alot of parts changers waste alot of money throwing parts at a problem when a simple piece of sandpaper can solve the problem

[MrGoodpliers]

I agree with Kelsfine69. With headers, the stock starter won't cut it. I had a '34 Ford with a 327 and blockhuggers and I went through about 5 new starters before putting a Tilton on. Never another problem. I've also used Powermaster starters and they are just as good and a little cheaper. But what I REALLY like is my stock starter and stock manifolds on my Burb.

[67chevemall]

Change the aspestos white ign wire to a 12g with good insulation from dizzy to the fuse box.

Buy a mini starter with zero heat sink.....

Done...

[Rdub]

Couldn't agree more with cdowns.... I had same exact problem & thought it was the starter.... happened to pull the side mount ground cable at the battery & noticed inside the rubber boot which surrounds the cable end, was corroded... cleaned it up and no problems since.