khinton

My 68 gto starts and runs great but after a 30 minute or so run it turns over very slowly when trying to start again like stopping and turning the engine off to get gas. When It's cold it turns over normally.

 

Rukee

Welcome to the forums.
I`d say your starter is heat soaked, bad battery cables or you may have too much ignition timing.

khinton

Thanks, timming was checked and is right on--new battery and cables show no corriosion. What is starter "heat soaked" and how do i fix it?

05GTO

Heat soak is when your wires and/or starter are overheated causing excessive resistance and does not allow enough current to start the engine. Best way to fix would be to inspect all wiring and route away from exhaust manifolds. May also be a starter in the early stages of failure.

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Randy

VettenGoat

I used to have the same problem with my 68. Its fairly common particularly if you are running headers. A heat sheild between the solinoid and exhaust will help some, but my guess is you'll be replacing your starter soon. Mine got so bad I had to wet it down with cool water just to get to start, replaced it shortly thereafter and fabricated a tin shield for the solinoid. Worked fine after that.

Mike

MPR6679

I had the same thing happen a few years ago with my '66. At at cold crank, the starter pulled around 250 amps. On a hot start, it was around 650 amps and was very slow to crank.

The battery was quite weak, and the cable ends had quite a bit of corrosion. A new battery was installed as well as heavier gauge cables. These repairs did NOT fix it, though it did crank marginally faster when hot. The starter was removed and inspected, and found that a combination of heat and excessive resistance caused the contacts inside the solenoid to become severely pitted.

The starter was rebuilt, and it fixed the problem. I added a heat shield afterwards to try to prevent future heat-related failure.

Rukee

^^ Good job ! Welcome to the forums.

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Restoration pictures password is 'GTO'

ppurfield001

Rukee, your car looks sweet and surely will turn heads this summer. Glad to see that you recovered from the rains. Regards, Paul.

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70455goat

Funny!!! I have the exact same problem on my 70. I am pretty sure I know what it is. In fact, I already have a new starter soloniod sitting on the work bench.

Had the exact same thing happen to my son's chevelle and it was the starter solonoid. Replaced it and the problem was gone. He has headers that was heating up the solonoid. One of these days, I want to put shorty headers on it.

I still wouldn't rule out some of the other ideas: timing, wore out &/or loose wiring, headers heating up the starter/solonoid.

Good luck,
Dale

binaryartisan

I used to have the same "heat soak" issue, but replaced starter core with a bar-wound armature. Solved the problem. Costs more though, check with a rebuilder.