Engine won't restart when hot

[gpzrider]

New to the website, glad I found it! Got a free 1973 Centurion convertible from my brother in law when he moved to Wyoming. Tried to buy it from him numerous times but instead he left it out in the wind and rain for 10 years, so now I have my work cut out for me. This is probably a really easy question but I'm not a mechanic so here goes. Car runs perfectly but then when gets hot and try to restart, it won't. If I wait around 30 minutes it starts fine. Any idea what I need to replace to fix that?

[centurion 455 ragtop]

If it spins freely and not sluggish I would check ignition first.

First off look at the distributor is it an HEI replacement? An HEI distributor is larger than a points distributor. If you have the smaller points style cap. Open it up (4 screws) Take a look to see if it was converted to electronics (there will be no points just a round pick up on the shaft and a black module) Electronic ignitions are better but when they crap out your stuck unless you have a spare tucked away in the glovebox. They are not expensive to replace.

Reason being is with electronic ignition if the module is bad sometimes when it heats up from a running engine it can fail. And once the engine cools down it will start again.

Next: If you try to crank it when hot and it's sluggish turning over and not quite doing it. Check your battery if it does it with a good battery check the engine timing, it is way too advanced and should be backed down. A safe timing on a Buick is about 32 degrees.

[gpzrider]

Thanks for the fast reply. Small clarification, when it gets hot and I try to restart it, I get NOTHING. No sluggish turn over, no clicking, nothing. 30 min later just fine. I'll check the distributor as suggested and then maybe I'll have more info.

[centurion 455 ragtop]

OK

Skip the distributor part. First check the battery cables. Remove the battery and just check the cables to make sure they did not corrode or split open.

If that checks out good and the battery is not old I would bet the starter is the problem. The solenoid must be shot that when the windings get heated up it will not spin the starter motor.

It cannot be the ignition system as you cannot even turn the engine over. If it was the ignition switch or fusable link or neutral safety switch it would not start at all any time. Only think left is the battery, cables and connection or the starter. Start with the cheapest and easiest. Inspect the wires and connection. If you have a voltage guage check the battery when the car is running to make sure its charging enough. When the car is very hot hook a voltage guage to the battery and have someone crank it over. If it doesn't crank over and there is no draw or severe voltage draw it's the starter.

The starter is fairly easy to change and a rebuilt goes about 70 bucks or so.

[EEE]

How hot is hot?

[gpzrider]

Thanks Rick. Will try out all suggested remedies. In response to EEE's question, normal operating temperature. I'll drive it for about 45 minutes from LA to Malibu. Engine light never comes on or even elevated temp guage. Then after stopping for ice and beverages...nothing. I even tried hooking up a portable jumper battery pack to it thinking it needed the extra juice to start but that didn't work either. But sure enough after 20 minutes of cooling down starts without hesitation.

[Robroy]

Welcome to the board GPZRIDER,

In the starter the two coals get worn by time which makes them jam in the wrong position and the starter wont work.
What you could try is to give the starter a good hit with a hammer which will make the coal(s) jump back in correct position again, IF that is the problem.
If this works you need to replace the coals in the starter which fairly cheap and simple, but very often the axle /collector inside the starter has got overheated and is damaged too.

I hope this translates correctly, good luck!

[MichelHaak]

Maybe a new high torq starter is a good idea..:laugh:

[gashog]

Any chance the car has headers?
If it does there is a chance the heat off the headers is heating up the starter.
You may want to insulate the starter if this is the case.
Otherwise replace the starter and solenoid.

[Smartin]

I had a problem with headers and my starter getting too hot, but it would click when I tried starting it. I'm lost with your situation, not having any sound at all.

I ended up installing a heat shield on my starter.

[centurion 455 ragtop]

I had a problem with headers and my starter getting too hot, but it would click when I tried starting it. I'm lost with your situation, not having any sound at all.

I ended up installing a heat shield on my starter.


Its so true Adam. That small metal factory heat shield that most people throw away when they install headers is still very important to have on the engine. Years back with my GS I kept on burning out starters until I re-installed that small metal factory heat shield. After having it installed I had no more starter problems. It also acts like a protective shield for the starter wiring keeping the wires clear of the headers.