just bear in mind that bp and mobil use the same refinery in melbourne (well they did when i worked for them in 1996) as the drivers told me.
Shell has more additives and "detergents" per particle in their 98 octane petrol.
i use valvemaster additive every 2nd tank... just incase. sometimes i forget and every 5th tank. doesnt do much.

I have been runnung my 73 sedan on std unleaded for a while with no side effects.
The engine and carby have been rebuilt.
I asked my engine guy would he need to do the valve seats for this fuel and he said it will run unleaded with no drama's and bear in mind "unleaded" only has a reduced percentage of lead.
cheers Ade

I switched to bp ultimate pretty much as soon as i got my 1200 ('73 A12) and it ran better straight away. I was thinking about red line lead substitute, but i don't know if its needed... but hey, i'm having problems with my balast resistor or something atm, and its running like ####, so who knows...


he he he, it automatically blurs profanity.. he he he

nah ive been told a hundred times you can run the a-series motors on premium as they came with hardened valve seats

i always use it, i prefer Synergy as it is more consistant than Optimax

the car HAS to be tuned for premium unleaded to see any benefits in using it

um i had a mate that worked at a shell servo and he said he would get batches of complaints from customers every now and then with huge mechanic bills, the mechanics blaming the fuel they used for expensive damage to there engines

plus i also here shell has a huge batch of fuel they made at the moment that is dodgey and they are trying to find a way to modify it so they can sell it

enough to keep me away from shell, stick to the synergy i reckon (has same octane as optimax)

optimax was the highest rating a while ago (like when the PRC rules changed), but since then both mobil (synergy 8000) and BP have brought out equivalents

i tried running Unlead in my A12 with some lead additive, it ran like a dog wouldnt idle well at all.

i have 1litre of MOREYS additive left. used like few drops

OK

so I've just been to www.shell.com and found out that if your using Optimax in an A series engine and it was manufactured prior to 1986 (most in OZ) then you will have to use an additive to stop the valve seats wearing!

Bugger!

More expense

Andrew

For everyones info the highest octane pump fuel in Australia is currently Shell Optimax. If I remember correctly it's 3 numbers better than it's closest rival (BP).
I have recently been through this exercise because they changed the rules for PRC rally cars and they must now run pump fuel so no more Avgas for me

So does this mean that Optimax (or any other PULP) has no side effect on the valves of the a12??

I'm more than ready for a change!!

i recomend mobil synergy 8000 or bp ultimate over optimax, less additives aparently and my car idles rougher even when tuned on optimax. bizare i tells ya

I'm not 100% sure i know the later a12 motors are fine on ULP. I run all my Leaded cars on Premium ULP cos it give a better octane match to the old Super Leaded fuel recommended for these motors. The alloy heads should be fine due to the valve seat inserts being hard enough to withstand the rigours of life with ULP. The question remains should a Catalytic converter be fitted????