hot starting issue. Fuel Boiling????

Hi Guys, question for yinz engine gurus. So my newly rebuilt 350 has been giving me a bit of trouble since the rebuild, never had this issue with the stock motor. if I give the car a good run, getting all systems up to full operating temperature, then park her for more than 10-15 minutes, up to about an hour or so, she will not restart. Cranks fine but no fire. I have to crank until my battery is going down before she will light.....

Now if I shut her down hot and restart within 5 minutes or so it fires right up. or if I let it sit for a few hours fires right up. sits for a week or two, fires right up. Its definitely an issue with heat, I have heard of fuel boiling in the fuel bowls, could this be my issue??? if so what can I do to correct it???

the motor is a 72 350. custom pistons with 9.5:1 compression. heads ported and polished. stock exhaust manifolds. carb set up by Ken at Everyday Performance. TA 284 cam 475"-223'/.475"-230',110'. 2800 stall converter, TA stage 1 dual plane aluminum intake. Crane cams points eliminator. power timed with lighter advance springs and set at 34 degrees all in.

 

What carb are you running? Do you have the fuel return line to the fuel pump connected? This was originally installed to prevent vapor lock, which may be your problem.

 

yes the ports are blocked off. temp gauge is reading 185-195 maybe, when I go to restart after sitting its reading around 212 degrees.

any way to stop this evaporating fuel??? you think the aluminum intake is creating this issue Larry?

 

I am running a factory Quadrajet built by Ken. I have only two lines at the fuel pump, one feed from the tank, and one from the pump to the carb.

 

Should probably also check to see if you are getting a spark when it is hot. Coil may be worn out and getting too hot.

 

a carb spacer may also help some, if you can fit it.

 

Same on my GS.. I pop the hood, wait two minutes, remove the air cleaner lid, and it starts right up. Like yours it’s only cranky after a good run on a hot day and sitting for a few minutes. Even then it’s pretty random. Will be interested in what you find out.

 

coil is only a year old, spark does not seem to be the issue because if I give it a shot of starting fluid she lights right up.

 

Yes Larry, my engine builder blocked the exhaust passages in the head that used to heat the choke stove.

 

Thanks, yes I thought about that but my air cleaner is hitting the hood now, I could use a drop base I guess, if I knew this would work I would surely give it a try.

 

where do you get the Cam2 fuel?

 

do you have the aluminum intake on yours? I never had a problem with the stock engine but it had a cast iron intake...

 

Stock iron, it stays hot in there for a good amount of time. Funny that our situations are swapped as I never had the issue with a aluminum intake.

What’s your initial timing and what kind of air cleaner are you running?

 

you think the air cleaner could have something to do with it? I did change from just a standard chrome exposed element air filter for a fancy dancy covered Cadillac style metal air filter cover. Looks cool but maybe holding heat?????

 

Not sure bud, I was just curious as to what air cleaner you were running. Popping the hood and removing the lid works for me on those rare occasions, but I’ve been to busy to investigate further.

So I’m really excited to see what fixes yours