Hot petrol

[Tony Griffiths]

Many of us seem bothered by petrol pipes, pump and carb getting too warm, and I can remember this being a problem nearly fifty years ago. This made me think -  why do the vast majority of cars blow the air heated by the radiator straight onto the engine?

Cold air hits the radiator, then the warmed air is flowing over the carb, pump and petrol pipes. No wonder it vaporises in hot weather. And hot weather leads to more traffic, so stationary traffic has a lot of hot air heating up the petrol.

And to make things worse, the hot exhaust pipe is usually along the same side of the car as the petrol pipe!

Old minis and 1100s seemed rare, in directing the hot air away from the engine, exiting under a front wing. that makes more sense.


Your thoughts?

A wise saying: "Inside a carburettor, it's always winter". In other words, in the UK colder weather is the norm and carb icing can be a real problem (even today some motorcycles have heating elements around the intake manifold to cure the problem). Remember those air cleaners of old with an intake pipe that could be swivelled around to collect hot air from above the exhaust manifold and then turned around for warmer conditions? However, why fuel pipes were not better protected on older cars is, indeed, a mystery.
I had a car once where the previous owner had taken some considerable trouble to shield the carb and fuel pipes from exhaust heat. Even so, in hot weather the car still stumbled badly; on checking the engine when this happened I discovered that the inlet manifold was covered in condensed water and freezing cold; arranging for the manifold to be heated solved the problem. Edit. Just remembered: I rigged up a temperature senor and drove the car. The outside of the manifold read between 1 and 2C when the outside temperarture was 17C.