It all says "use them more" to me. If you can't, drain them. I've just fired up the 4CV after a 2-month gap, unusually long for me, and it went first time, perfectly. I use 91 fuel and tend to keep it full if there's more than a couple of weeks unused. I try to do 20 km minimum when I do start it.
At the other end of the scale, the exciting fuel MB used in their prewar GP cars had to be drained after every use because it was so damaging if left in the system. The interesting Hemmings website (https://www.hemmings.com/stories/20...omplexity-of-starting-a-prewar-grand-prix-car) says this about one of these remarkable cars that is located in Florida:
Consisting of 85-percent methanol, 10-pecent nitromethane and five-percent acetone, the fuel must be custom-blended in advance by supplier VP Racing Fuels. Its rarity makes it expensive, and it’s also corrosive to the magnesium components used in the car’s engine and fuel system; upon the car’s return home to Naples, Florida, the fuel system is drained, “pickled” to remove traces of the 85-10-5, then flushed with gasoline as a preservative.
Wow.
At the other end of the scale, the exciting fuel MB used in their prewar GP cars had to be drained after every use because it was so damaging if left in the system. The interesting Hemmings website (https://www.hemmings.com/stories/20...omplexity-of-starting-a-prewar-grand-prix-car) says this about one of these remarkable cars that is located in Florida:
Consisting of 85-percent methanol, 10-pecent nitromethane and five-percent acetone, the fuel must be custom-blended in advance by supplier VP Racing Fuels. Its rarity makes it expensive, and it’s also corrosive to the magnesium components used in the car’s engine and fuel system; upon the car’s return home to Naples, Florida, the fuel system is drained, “pickled” to remove traces of the 85-10-5, then flushed with gasoline as a preservative.
Wow.
