Talk Morgan Forums Morgan Sports Cars Maintenance & Servicing Fuel Vaporisation

I am just back from a 4,000 mile drive to Sicily and Malta from the UK in the 1980 +8. It was very hot in Southern Europe, 36-40C in the shade. Both me and my friends in other carb cars, 3 E Types and XK150 all suffered from fuel vaporisation. We filled up at separate garages and we have all driven in hotter temperatures albeit before there was bioethanol in fuel. I wondered if anyone else in warmer climes has struggled with fuel vaporisation since ethanol added.
Note: the Super fuel in Italy was 95 Octane and E5. Q8 sold 100 octane that was E10.

Not this particular issue but 15 years ago, when my MGB V8 was idling a long time at the MoT it would get hot, run rough and stall. It always restarted and only did it there. I added a woven heat resistant blanket under the float chambers which helped, but had it got worse, I was contemplating fixing up a fuel return pipe to the tank with a higher pressure pump.

A flow of fuel will cool down lines so it doesn't happen so much on injected engines. Having said that I had to operate the fuel primer to get a hot aircraft engine running sometimes as the mechanically injected engine did suffer from vaporisation on hot days. Operating it on full lean didn't flood the engine too much.

It's known to happen on Cosworth Duratecs, with the location of the fuel rail at the top of the engine it can get hot. It happened to a friends Caterham CSR260 on a not too hot day.
It happened to my old 323i BMW way back in the 80s, after a blast up the motorway from southern Holland to Schipol i got to the car park barrier and the engine died, pushing the car to one side and sitting for 15 minutes sorted it. Luckily there was a Dutch AA man there who put me wise.

Heat proofing fuel rails will help. Image below of Cyclone 3.7 V6 showing Ford's heat protecting material around rails in centre of V.

That is a very trick looking Roadster Richard. Dry dump etc. Is that the AR one?

If its the one I think it is, it has been meticulously prepared - verging on a full rebuild.

Here in Massachusetts it can get very hot and I have vapor lock from time to time. I've insulated the fuel lines and fitted a heat shield between carburetors and block (not sure if that actually helps). Also bypassed the mechanical fuel pump and fitted and electric pump to push fuel to the carbs. I try to avoid driving in high heat and dread the heat/traffic combo.

The later trads have the fuel lines running under the offside wing, within a few mm of the cat & exhaust, so I've added heat reflective weave to both lines, out and return. It's a fiddly job because access is tight unless you drop the exhaust, but a lot of heat gets contained under the wing on hot days.