Stupid question about 'leaded' gas

[Renthorin]

So I told a buddy I will be replacing my spark plugs and he asked how many miles on them. Said 30k and he said "nah..they are good for 100k these days".

I told him I run leaded fuel and the seem to foul quicker.

That lead to the discussion of what makes high-octane fuel high-octane.

He said the reason they put the 'lead' into the fuel is for the octane. I thought it was to protect the valve parts.

Is it both? Is it one or the other?

I didn't think lead had anything to do with octane and then I read this:

Tetra-ethyl lead - Wikipedia, the free encyclopedia

Help a confused boy out here....


will

 

[pacecarta]

its for octane but it did lube the valve seats , on cars built before leaded fuel the seats werent hardened like they are today

and with high ppm leaded fuel like c16 i'd change them after every race , some do them after every run
for lower ppm fuel like 100LL (which has lead)you could drive an NA motor a few thousand miles before you'd notice a problem from the lead fouling but i would put fresh plugs in before i got on it with a turbocharged engine

 

[davidf]

Can't be good for the 02 sensor either. I believe they make unleaded race fuel but I could be wrong. Just heard that somewhere.

 

[Renthorin]

they make 100 and 104 though I can never find them. I get about 4k miles to an o2 sensor (Denso) but as easy and inexpensive as they are....that's ok

I'm just bummed that he was right about the lead being the high octane part though I did say it was for valve train protection...so...we are both right.

 

[Dynaflow]

Tetraethyl lead was added primarily as an anti-knock compound...slowed the burn rate.

 

[DJJM]

VP has unleaded race 109...good stuff

 

[Renthorin]

oh sure....no dealers in Michigan :-(

I like my turbo blue 110...just didn't think the lead was the reason it was high octane.