1960 XK 150 SE; 3.8. Live in Southwest Florida. Experience vapor lock after driving 15 or so miles on a warm day. Lots of those here. Does not affect car while driving. But it needs to cool down for about half hour before it will restart. Running temperature is fine. Cold start is very good. Any suggestions?

 

Modern petrol seems much more volatile than the old leaded stuff, and even here in cold and wet England, there have been articles in the classic car mags about fuel vaporisation and how to avoid it. Essentially, its all down to stopping a build up of heat in the engine compartment and making sure the fuel lines and carburettors are not exposed to heat. . The Jaguar engine is cross-flow, so the fuel side is not next to the exhaust manifolds like it is on so many old engines. Assuming the car has been rebuilt in the past, is the fuel installation stock ? The supply side is very simple with a pipe from tank to fuel pump, then from there to the carburettors. You need to check the fuel lines aren't near any heat source. When you stop the engine after a run, the air flow through the engine compartment ceases, and heat builds up until it convects and radiates away. Is everything stock in the engine compartment ?

 

Thanks for response. Pretty much what mechanic has said. Engine bay rebuilt/restored using stock although not sure about fuel pump. Mechanic does not think insulating fuel line will help much. Input and output on opposite sides of engine block and car frame so I assume exhaust heat is not affecting fuel lines. Read online that repositioning fuel pump closer to the fuel tank could help but not sure why that is true. Have electric fan for radiator. Wondering whether a properly positioned additional fan might dissipate heat faster. Again, thanks for the input.

 

The change of vapor lock on a XK150 is almost impossible.
All fuel lines, pump and carbs are opposite from the exhaust side.
looks more like a fuel pump issue.

Regards,
Peter Jan
(XK140, XK150 3.8, S-type 3.38 )