Hot weather causes poor engine performance?

[TraeZ]

I recently was in stop and go traffic and I noticed that as I was coming to a stop, that all to uneasy feeling that the Z was about to die came on. It was running hot that day and the temps had been in the 80's for the first time this year.

Sure enough after a couple more stops I had to get off the hwy and let her rest for about 30 min. I was able to drive home after with no heat issues????

The car is a '73 240 with an after market A/C unit which includes the A/C radiator (which sets in front of the car's radiator). I have the original round tops and intake with Summer/Winter on it (set to Summer).

Does this sound familiar? Can it be corrected? This is my daily driver and I can't afford to have this issue with summer coming on !

Thanks!

Trae

[240znz]

Have you looked into the possibility that you have vapour lock?

[TraeZ]

No, I hadn't thought about that! I'll have my mech. look at it when he has a chance, unless you can give me a quick tutorial?!?!

It has had this problem before but only in hot weather

[240znz]

I haven't experienced it first hand but do a search using "vapour lock" and you'll find heaps on the subject.

Trace the fuel line from the fuel pump to the carbs then back and you'll see that it passes around the rocker cover. Fuel can vapourise in the lines therfore stopping the carbs from functioning (carbs like liquid fuel not as a gas). Fixes are various but maybe start by insulating the fuel rail. There are negatives to that though, such as once heat is in there it is harder to get out?

So do a search in the forums and you'll get to read all about it. Lots of opinions on why and how to rectify.

Good luck.

[240ZX]

Your first clue to your problem should be......you own a 32 year old car!!! Additionally, without anyone knowing the current condition and service history on your car, you might as well ask a rock for answers. If your car is prone to over heating, its definitely a cooling system problem. Let's see...you have a radiator, radiator cap, hoses, thermostat, temperature sensor/gauge, water pump, water pump drive belt, fan assy, coolant, a heater core/valves and an engine the coolant is supposed to cirulate through and draw heat from . This should give you enough information for a good starting point! Let us know how it turns out.