Lead free gas?

[brokke]

Hi,

Here in the Netherlands there is an ongoing debate concerning the necessity of using lead substitute in older 911's. I have a 1972 2.4S american car. What is the opinion in the USA?

Peter
911 2.4S

[dvkk]

In western Canada leaded gasoline was banned in 1990. Not one car here has used leaded gas for 13 years. I have not heard of one failure of any make of any car in that entire time. This whole leaded gas fear is just like the Y2K fear 4 years ago. And you remember what happend then.

[sammyg2]

Tetra-ethyl lead served three purposes:
1) it increased the octane rating of the gasoline
2) It acted as a cushion on valve seats (very important on some older cars that did not have hardened valve seat inserts, 911s don't fit into this category)
3) it added a very small amount of lubrication to certain parts, like valve guides. (note, the lead made a very, very small difference in lubrication).

Porsche 911 valve seats are hardened and do not require lead to cusion them.
Most lead substitutes do not add any measurable lubrication of wetted parts and does not make much difference in valve seat wear, they only raise the octane rating a small amount.

So...... if the unleaded gasoline you are using is of a high enough octane rating to prevent pre-detonation and pinging (not necessarily the same thing) IMO you do not need a lead substitute in your 911.

If your gasoline is too low as far as octane, you might need it.

[Bill Verburg]

Porsche used the hardened seats that are necessary when unleaded gas is used at least as far back as 1966. Not to worry!

A seat w/ a Rockwell hardness of 45 - 50 is necessary for protection w/ unleaded fuels.

'66 911 used RA65
'69 911 used RA54
'76 911 used RA64

The hard seats along w/ the 911 valve rototors will prevent problems.