Won't start when hot!

[chevy72pu]

Ok, so the rebuilt 350 runs like a top, no overheating, no leaks. All is well till I shut it off after more than 7-8 miles of driving. It will not restart until it sits for 30 mins or so. The battery turns her over fine when she is cold, but can't manage to do so when the engine is hot. Swapped the battery out of Lil' Red and the same thing happened. We put double hump heads on the 350, so I'm wondering, do I need a new stronger battery or a high torque starter? BTW it will crank with a jump start even when it is hot. I had Advance Auto Parts check it and the print out showed a 25 amp drop on the battery and the alternator is fine at idle.

[DT1]

Same thing happened with mine a while back. It would crank very sluggishly. I thought the timing was just too far advanced but It was just a tired starter. I changed it out and it cranks like crazy now.

[Gene]

Make sure all your connections are good, I had same problem but my hot wire from battery was hanging on by only a few strands. It looked ok but when I took starter loose the wire just broke in half.

[LockDoc]

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I would say it is one of two things.

Gas is boiling in the carb float bowl or the starter and solenoid are suffering from heat soak. When the starter and solenoid get hot it degrades performance.

I had the starter problem so I decided to get one of the mini starters so it would have more air space around the starter. I had no more hard starting problems after that.

Usually with the gas boiling in the float bowl problem it will show up after setting and idling for a period of time and the temp rises. When you accelerate after setting at idle for a while the engine will run fine for a minute or so then start running really crappy and will not accelerate. It acts like it is starving for fuel, which it is. You can usually cure this problem by installing a 3/4 or 1" phenolic spacer under the carb.

Just a couple of things to think about.

LockDoc

[oldgoalie]

I had a 69 c20 that did that. It was a bad battery cable. It was the pos cable. It looked good but it was coroded inside the sheathing about 10" from where it bolts to the starter. I think maybe, the heat from the exhaust. Replaced it, no more problem.

[cdowns]

in the edelbrock carb installation instructions they warn of this problem and suggest using a phenolic carb spacer

[Gene]

Originally Posted by cdowns

in the edelbrock carb installation instructions they warn of this problem and suggest using a phenolic carb spacer

I installed one under my edelbrock Carb and it did help some, but the problem is still there.
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[lil hoodlum]

Originally Posted by Gene

I installed one under my edelbrock Carb and it did help some, but the problem is still there.
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I did the same for mine as well. I also apperently had mine air/fuel ratio too lean. I guess that makes it run a little hotter.

Keith

[Andy4639]

Well mine is fuel injected so I know it wasn't the boiling. After swapping to the Orileays super mini starter mine has never had trouble again.

Here is the thread on the starter. Over a year now and it's never gave me a bit of trouble even after driving hours.




http://67-72chevytrucks.com/vboard/s....php?p=4151565

[chevy72pu]

Thanks for all the ideas, guys. I don't think fuel is an issue, 'cause the engine runs fine once I get it started. No starving or anything. The battery cable to the starter is short and needs to be replaced with a longer one anyway, so that will be a good place to start. The starter on the truck now appears to be new or recently rebuilt so it should be good. If that doesn't fix it then I'll prolly go with the mini starter in the thread. Will keep you posted.

[scrappy ron]

i think it could only be one of 2 thinks its ether the timeing or a bad Coil when coils get hot it wont start i would check that for sure

[50bomb]

My grandpa's 64 chevy truck does the same thing almost everytime he comes over here to my house. It happen again yesterday so it is on our driveway right now. How about the Distributor? do you think it could be the ignition rotor in there?maybe not tight enough or the lil chrome arm is not far/closed enough? No sure which one. He has a sbc350/th350. Grandpa made me laugh when he was walkin away from his truck. He said some choice words in spanish. I feel his pain. Put so much money in them and they want more attention haha.

[scrappy ron]

Originally Posted by 50bomb

My grandpa's 64 chevy truck does the same thing almost everytime he comes over here to my house. It happen again yesterday so it is on our driveway right now. How about the Distributor? do you think it could be the ignition rotor in there?maybe not tight enough or the lil chrome arm is not far/closed enough? No sure which one. He has a sbc350/th350. Grandpa made me laugh when he was walkin away from his truck. He said some choice words in spanish. I feel his pain. Put so much money in them and they want more attention haha.

i bet you any thing its the coil i would check it. its a vary comin proble

[bbadfred]

No matter what you do find get a mini starter anyway! You will never regret it!!

[gcburdic]

check this thread for a mini starter that weighs just 7lbs and is $60...http://67-72chevytrucks.com/vboard/s...d.php?t=521843.....This will be the route I go next time I need tho change out the starter.....better than laying on my back trying to get that 20lb starter in place Let us know what works for ya!!!

[jchav62]

The timing may just be a little too advanced. When I first saw your pic and saw the Edelbrock carb, I was going to blame it (heat soak) but after reading your post, I realized that's not your case.

Also, like the other's said, check your positive cable from the start... and make sure the terminals are clean and tight.

Good luck... JC62

[coop34]

Originally Posted by gcburdic

check this thread for a mini starter that weighs just 7lbs and is $60...http://67-72chevytrucks.com/vboard/s...d.php?t=521843.....This will be the route I go next time I need tho change out the starter.....better than laying on my back trying to get that 20lb starter in place Let us know what works for ya!!!

I had the same problem, and switched to this mini starter. Has started up every time since. $60 to my door.

[bowtiecharlie]

I had a 72 short bed that would not "crank over when hot"! You could jump the starter with a screwdriver and it would start, but not with the key!! After weeks of new parts ,battery,starter,ns switch, ground wires to the frame and fire wall ,I found that the wire that runs from the Positive batt terminal to the fender (black junction block) was shot!! I cut and soldered a new wire terminal on it and it was good as new!! You should also have one from the Negitive cable to the fender direct,with no junction block!!

[fastwillie 696969]

good thing its not a blower engine

[chevy72pu]

The timing thing could be it. We advanced it to the limit and then backed it down a hair. I didn't mention this earlier, but it does "diesel" for a few seconds when you shut it off. I usually just ease out on the clutch to stop it. I'm not gonna change too many things at once so I can tell what corrects the problem.

[doubleb's69]

Nice looking engine bay. Is your lower radiator hose resting against your fuel line. If so that would really aid in the transfer of heat to your fuel and like LockDoc said it would boil while idleing. My truck would run fine once started as well but it would eventually just shut off with the factory cast iron intake and then I would have to let it sit and cool down to get it going again. I put a new aluminum intake on and put on a set of cross over block off intake gaskets on and it seems to be ok now.

[70cst]

Originally Posted by LockDoc

-
I would say it is one of two things.

Gas is boiling in the carb float bowl or the starter and solenoid are suffering from heat soak. When the starter and solenoid get hot it degrades performance.

I had the starter problem so I decided to get one of the mini starters so it would have more air space around the starter. I had no more hard starting problems after that.

Usually with the gas boiling in the float bowl problem it will show up after setting and idling for a period of time and the temp rises. When you accelerate after setting at idle for a while the engine will run fine for a minute or so then start running really crappy and will not accelerate. It acts like it is starving for fuel, which it is. You can usually cure this problem by installing a 3/4 or 1" phenolic spacer under the carb.

Just a couple of things to think about.

LockDoc

I had the exact symptoms and it was the starter with Heat Soak problems.

[71swb4x4]

Originally Posted by chevy72pu

The timing thing could be it. We advanced it to the limit and then backed it down a hair. I didn't mention this earlier, but it does "diesel" for a few seconds when you shut it off. I usually just ease out on the clutch to stop it. I'm not gonna change too many things at once so I can tell what corrects the problem.

Before I even read this post I was going to suggest timing as a couple of others have. I had a 72 that did exactly what you describe, and it was the timing, I had advanced it too far. It would also diesel sometimes when shutting it down.

[Boog]

If the engine spins over fine cold but grunts when fully warmed up it's most generally the starter heat soak problem. If the engine spins over normally when cold or fully warmed up but won't start up it's generally a fuel issue.

[502ms]

Originally Posted by Boog

If the engine spins over fine cold, but grunts when fully warmed up it's most generally the starter heat soak problem.

Agreed
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