(Tim Renouf) Writes :
>
> At the weekend I bought a book called "Tuning the Rover V8" by
> David Hardcastle. This book claims that you can run any post-1970
> Rover V8 on unleaded, although to run the UK-spec 9.35:1 on the
> 95 octane stuff you get in the UK you would have to retard the
> timing by 3 degrees. Has anyone with a UK-spec engine tried this ?
> Does it affect performance much ? I have a TR7 with a pre-81 UK SD1
> engine in.
Now that's interesting. My SD1 owners manual (the Britain printed
one) says to only use "4 star leaded" 97 octane fuel. This is
referring to the 9.35:1 British spec and not the 8.13:1 Australian
spec. A friend has a 9.75:1 Vitesse engine and that ran fine on our
leaded super, 97 octane, until they lowered the octane to 96. I'd
expect the 9.35:1 car to run on 95 octane fuel.
For post '70 V8s it's the octane rating which is the problem. The
valve seats are the same on all models (bar vitesse) including the US
models which ran unleaded. The real problem with running unleaded in
a leaded car is not the knocking, which is easily fixed, but the
pollution.
Leaded fuel gives off lead in the exhaust which retards the growth of
young children and can lead to brain damage. Unleaded fuel,
especially high octane types, contain aromatics like benzene and
toluene to boost the octane rating. Without the catalytic converter a
significant amount of these are spewed into the air. Aromatic
compounds are carcinogens and cause lukemia. The technical adviser at
our club considers the aromatics more dangerous than the lead and
therefore won't use unleaded in any of his cars not equipped with a
catalytic converter.
I've recently switched back to the slightly more expensive leaded
fuel. In the future I hope to build a warm engine which will be
fitted with a generic catalyic converter.
--
_--_|\ -|- Gavin Walker
/ \ |
\_.--.*/ <- Canberra, gavin@csis.dit.csiro.au
v Australia Phone +61-6-2750964 Fax +61-6-2576325
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