Vapor lock? Running hot

[Gary1961]

Hello I am looking for some help. I have a 61 Hawk with a 289 2 barrel flightamatic. I can not keep it running once the temp gauge hits 180. I have triple flushed the rad water pump and fan is working. I also rebuilt the carb which still has a stumble in it. I thought it was vapor lock,so I eliminated the mechanical fuel pump and installed a Mr.gasket12s vane pump with s regulator and pressure gauge. I have been adjusting the pressure down starting at 4 psi. Car at any pressure will not start once temp gets to 180. It will start and run good around 135. Thanks

[Squatch]

I think a good look at your ignition system is in order. 180 isn't too hot for the engine, and vapor lock is a pretty common problem when starting a hot engine, not so likely to shut off a running engine.

A quick and dirty test that may prove an ignition problem is to use a timing light while the engine heats up. If a nice steady indication on your timing mark gets erratic as the engine starts to run poorly, you'll know where to focus. If it just stops when the engine dies, it's less helpful.

[pinehurstbob]

Try a return line. Did the trick on my 2 Larks that are 259 Auto trans, 2 barrel carbs. I used the mopar fuel filter and put a fitting in the gas filler neck.
Bob

[64studeavanti]

Check heat riser.

[jg61hawk]

I have a 61 Hawk as well. My thoughts...If it just dies as it heats up to 180 or less I would think the condenser is probably heating up and opening internally....as the car cools the little thing closes up and the car starts. They are little trouble makers. The radio "condenser" attached to the coil can give you a problem if it internally shorts out. Remove that or cut the wire. The car should at least fire with some gas poured down the carb if it really is "vapor lock". So let's step back....the car starts and runs (but has a stumble) it warms up and dies. Immediately pour some fuel down the carb and crank...fire up...ok a fuel issue....no fire spark. OR it dies....pull a wire and check for spark with the old screw driver up the wire ( or a finger if really old school). My car would vapor lock with the Ethanol fuel as it reached 210+..... I had the car over 46 years. It never had a problem in the old days with regular gas, but the corn fuel boils. Another fix is if in fact it is vapor lock, install an electric fan, and or block off the center of the intake manifold....that heats up the carb.... (at least that is a cure on a 4 bbl.) . It should run at 180 even with corn gas.

[BalkaRoo]

I have seen dodgy "coils" do similar things! they can become heat sensitive and erratic to the point of stopping, and then after a while start up and repeat the problem. At least it's an easy check to see and cross off the list. I agree with jg61hawk as well, condenser trouble can be hard to identify. Remember the old saying that 90 percent of carburettor problems turn out to be electrical!

[bensherb]

I agree with posts 5 and 6. Replace the condenser. Coil problems aren't usually so dramatic, but they can be. They're also more expensive than a condenser, start with the cheap stuff first. Also, if the condenser has gone bad the points may not be in great shape, take a good look at them and replace if needed. OR, replace the ignition with an electronic one and you shouldn't have to think about it for decades.

I have several points ignitions for my Stude V8, and the one that was in my car worked fine. I built a GM HEI (electronic ignition) to replace the points one. I gained a much hotter spark, more complete fuel burn, a smoother idle, more consistant spark at high rpm and zero maintainence; it's been working great for 9 years now. The one I built for my '72 Ford 390 has been working great for 35 years without ever being touched.

[Gary1961]

Thanks to everyone. I was thinking about switching to electronic ignition. So you guys made up my mind. I did replace points and the same problem was there. I never knew about the condenser. Thanks again

[jg61hawk]

Gary, thanks for the update..... please keep us updated on the situation as we all learn from each other. I prefer to stay old school, so I would be very interested if the situation was actually electric and not fuel. I also would like to gloat that I was right, being married I rarely get the chance!!! On the other hand you can just replace the condenser for the time being....? A conversion the electronic is a little more complicated than just pulling the distributor. The resistor wire or ballast resistor comes into play....I'm no expert on this....be sure you have the instructions or a good mentor. Old school works...it may be easier.

[bensherb]

I measured that pink resistor wire when I swapped to the HEI. It was insignificant, so I just connected it to the power input of the HEI. Works fine for me. I was just too lazy to remove the pink wire from the harness at the time. I could have just cut off that pink wire and laid a new wire along the harness and wrapped it to the harness, as I have done with several added wires since, but you know; too lazy, busy, whatever, at the time!

[Jeffry Cassel]

Another vote for coil. Very common for a coil to heat up and fail. A condenser could too. Check for spark when hot. Also NEVER use a vane type fuel pump. You can't hear them running and they are not self priming. If the car sits for more than a few days. you ain't gonna start it without a lot of suckin' and/ or blowin"! The fuel line from pump to carb runs pretty close to the front of the left exhaust manifold. I have a 1961 Hawk that I bought from my NCOIC in 1970. I drove it daily while living in Texas and never had any over-heating problems. Of course it was being fed Fina regular gas which probably has a vapor pressure a tad higher than today's crap -gas.