leaded/unleaded

[Lang]

Michael,

I did quite a lot of research on this for our club a few years ago and the conclusions I reached were:

The original leaded fuel definitely contained products (not only lead) that "cushioned" and lubricated the stems of the valves.

Long term use of unleaded fuel and continuous high speed running sped up valve recession ie wear. Catastrophic failure was not a feature of any of the studies I looked at.

The generally higher octane of modern unleaded fuel has compensated somewhat for the loss of lead with its slower burn rate and avoidance of detonation or pinging on the longevity of the valves.

Quite a number of early 40's and 50's vehicles had hardened valve seats and unleaded fuel is not a factor. You can also get hardened replacement valve seats for almost any type of older engine.

Upper cylinder/lead replacement does an excellent job in covering all the lost benefits of lead.

Bottom line was, with the number of miles and slower speeds 99.9% of our old vehicles travel at it does not matter a damn if you replace the lead or not.

To be fully happy use lead replacement but the chances of you being much better off (with our type of vehicle, not high performance classic cars) than non users is slight.

Lang