Fuel question

[JohnC]

Hi All,

Should I add lead additive to my fuel? and if yes should I use premium gas?

[Barry Wolk]

There is no reason at all to use a lead additive, unless you like unnecessary polluting the environment. They were needed for old cars for a very short period of time while fuel manufacturers figured out a way to use other means to prevent burned valves. By this time most Mark II engines have been fitted with hardened seats as a matter or rebuilding the heads.

If you burn up one tank of gas a summer there's no need for fuel stabilizers, either. Fill up in the fall and the gas will be fine in the spring.

There is something that I've found to be of benefit is to use oil with a zinc additive. I use it in my 28 year old Kohler 20kw stationary generator, too.

I suppose, if you really wanted to do something that will benefit the car, just drive it.

I burn premium in my ExMark zero turn. If it's good enough for my lawnmower, it's good enough for my car. In fact, since I got my 389-hp hybrid I've used more gas in my lawn equipment than my daily driver.

[Shelly Harris]

Unlike modern computerized engines of today which can handle any gasoline you give it. .including the lowest octane on the pump, our Mark II engine called for the highest octane rating gasoline commonly available which was 100 Octane or higher. I fill up with the highest octane on the pump and additionally dump in a bottle of octane booster. I also add a can of lead substitute as I don't agree with Barry... our original valves demanded lead.. If I'm wrong it's still cheap insurance.

I agree with Barry on making sure your oil changes are 6 qts (with filter) of oil designated for "older cars" which probably are spiked with zinc.

[Egenolf]

Here is a short excerpt from a test of the Mark II (Popular Mechanics, September 1956):



Otherwise I agree with Shelly: if the engine is original, the valve seats demand the lead.

The engine of 2503 got hardened valve seats due to the overhaul so that I can use unleaded fuel.

The ignition timing of 1966 is set to 12 btdc, no knocking because I refuel 100 Octane gas. Fuel economy is 13,4 mpg.