Just wondering what fuel & additive, if any, the Aussie guys are using.
I have a series 3 4.2l with twin su's.

 

Rick in my S2 4.2 with SU's I use premium 98.....no issues so far.

 

ALL my Jags have used 98 ever since its been around, no special thoughts from me.

They all ran Super back in the day.

 

Thanks guys.
It apparently had an exchange engine in 2000 so one would hope that it was built for unleaded.
Premium is good, the Harley & the Chev both drink it.

 

98 here too, 95 from the servo's that don't sell 98.

I ran Flashlube Valve saver up until I got my new engine not requiring leaded fuel. Nobody could tell me if I should run it or not,and many people told me it wouldn't do any harm.
Enough to treat 1000 ltr's of fuel is available at Supercheap Auto for $17.

Flashlube Valve Saver Fluid: Flashlube fuel additives Synthetic lubricants for the automotive industry - Genuine Flashlube?

 

The 4.2 doesn't care if the fuel is leaded or not. And,
a lot others tolerate it. Machine shops made a lot of
money with that tale.


As I understand it, the fear was that steel valves on iron seats
needed the lead to lube and soften the impact??? Consequence
was beat out seats and valves buried.


Install steel seat inserts! Oh, gee the alloy heads already have them...


Carl

 

Pretty close. The lead in the fuel acted more like a non-stick compound between the exhaust valve and it's seat. Under extreme conditions (wide open throttle going up steep grades) the valve and seat could get hot enough to momentarily spot weld themselves together as the valve closed. When the valve opened again, this micro-weld would be broken and a tiny piece of material would lost.

Over thousands of cycles, the valve and seat, usually the seat would be destroyed.

There was great panic when unleaded fuel was introduced fearing the above and as stated many machine shops made a fortune by installing hardened seats. In most cases it was not required as the engine rarely or never got pushed hard enough to cause a problem.