"Peter Sheppard" <peter (AT) puffer-nutter (DOT) co.uk> wrote

The B series was a bit fussy about fuel it really preffered the much mourned
5 star, as for timing star at 10 deg BTDC and retard it a tiny bit at a time
untl it stops pinking -- pinking is usually associated with low to medium
rpm at full throttle to test for pinking warn the car up and ascend a hill
in a high gear with full throttle from low(ish) RPM. If you hear a tinkling
sound retard the ignition by degree increments until it just stops - then
retard by an extra degree for safety.

Aviod excessively retarding the ignition as excessively retarded ignition
can lead to over heating and running on due to the increase in heat rejected
to the cylinder walls. Ignition timing should always be before TDC if you
find the timing approaching TDC you may want to consider using an octane
booster or lowering the compresion.

In article <beo8ic$8sa$1 (AT) hercules (DOT) btinternet.com>,
AWM <nothere (AT) nowhere (DOT) freeserve.co.uk> wrote:
Strange considering that 5 star wasn't around when the 1500 saw the light
of day. Some of the various 1600 or 1800 models, perhaps.

FWIW, I've had several 1500 versions and never had any problems with
pinking on 4 star. Mind you, I usually blew them up long before they'd
have needed a de-coke. ;-)

I agree about your timing method, though. Modern fuels are so different
to the originals the makers timing figure can only now be regarded as a
rough guide.

--
*He who laughs last has just realised the joke.

Dave Plowman dave.sound (AT) argonet (DOT) co.uk London SW 12
RIP Acorn