Premium iso Leaded

[bigredddaddy]

We've got a 1963 Corvair for my step daughter and a couple of people say you don't need lead-ad if you use premium. Myself, I was told that the lead was for the valves. I've owned only one car that used leaded and I used the lead-ad so I'm in the dark on this one.

[73hurst]

The idea of using leaded gas, besides the added octane, was that the lead cushions the valves when they come in contact with the valve seats, and thus minimizes wear on the seats. The solution is to have hardened valve seats installed, like cars designed to run on no-lead gas. Some reports state that the wear from using no-lead gas and non hardened valve seats is negligable, and not worth worrying about. The idea of using premium over regular unleaded gas is more a factor of compression ratio, and the engines reaction in terms of knock and ping. Higher octane premium will resist knock and ping better than regular gas, more so in an engine with a high compression ratio. Basic thought, is that you can run a compression ratio of 9.5-1 to 10.0-1 on pump gas without additives. Modern engines are a different matter all together, and can run higher compression ratios on pump gas than the older engines of the '60's or '70's for instance.

Pete