How full is your tank ?

[richkaz]

I've read various idea's regarding how much petrol should be left in the tank of
any older classic / vintage car that's not used regularly. I experienced problems starting my Flaminia ( with Bendix mechanical pump )
if it hadn't been started for more than a couple of weeks in the winter. In the summer it seems fine.

The argument in favour of keeping the tank well topped up appear to be.

1. Little chance of condensation from the tank dripping into the petrol. causing starting and possible serious engine problems
2. Less pressure required for a mechanical pump to suck up gas if the carbs are completely dry and need some help ?
3. No need to hunt around for quality petrol if the mood takes you to take the car for a quick spin
4. Less chance of sucking up debris from the bottom of an older tank
5. If gas prices are rising, you filled up at a better price.

Against.

1. Petrol not quite as fresh as filling up every journey
2. Carrying unnecessary weight and reducing MPG
3. Greater fire hazard in the garage or in an accident
4. If gas prices are falling -----------

Any thoughts ?

Thanks

Richard

[Randy Adams]

Richard, I confess that all three of my Flaminias were converted to electric fuel pumps. For the two which currently run (1961 GT convertible & 1958 berlina) I try to make sure each is driven every single week, with no more than a two week lapse if that's not possible. I fill the tank with a brand of gas known in California for being comparatively stable. Most of the time I will refill the tank in about two months' time though I also never let the level go very low. Usually there are 4 or 5 U.S. gallons remaining in the tank when I refill it. That is not by design so much as a consequence of the wildly unreliable fuel gauges on each of the cars, thanks to the sticky sender and saturated cork float. Two of my cars have the reserve tank feature and the tap on the floor. I do not trust it and never touch it. It's an awfully old valve which can be counted on to leak dangerously if it fails.

With terrible U.S. gasoline laced with ethanol, I have found that the jets in the carburetors will become clogged if I am lazy about driving the cars. When that happens there's nothing for it but to remove, disassemble and soak the carburetor components in cleaning solvent. When it's back together and reinstalled the car runs beautifully! But that's an awful lot of work rendered unnecessary if I just keep driving the beasts.

If you haven't done so you will ultimately find it profitable to remove the fuel tank and have it cleaned out and any corrosion repaired. Garbage at the bottom of old fuel tanks is a notorious source of old car reliability problems.