Pat,
>Mk1 2L Vitesse. I chose to use the regular unleaded (91
octane) fuel, but
>now need some advice on what adjustments I need to
make (preferably not
>involving a syphon tube!) to make the engine run
satisfactorily.
>Presumably the iginition will need retarding (currently at
12 btdc static,
>with the UK spec 9:1? head). Can anyone estimate
roughly by how much?
>Will the mixture need readjusting? Is there anything
else? Once the
>ignition is retarded is the engine more likely to overheat
in traffic?
I converted my 13/60 to unleaded about 5 years ago by
fitting a head that had been fitted with hardened exhaust
valves and seats. At the time, it only cost about 30 UK
pounds (100 as opposed to 70) more than a reconditioned
unmodified head so I went for it.
The ignition certainly had to be retarded which I did by
experiment i.e. retard until it doesn't 'pink'. The setting
was around 6 compared to the standard 9 BTDC. Apart
from that I've had no problems caused directly by the
change. Annual mileage is only around 3 - 4000 but there is
no sign of an valve seat recession. Performance seems
about the same as before (which isn't a lot, I grant you).
The general wisdom seems that there is no point doing
major things to the head unless it needs reconditioning
anyway, as in my case.
Resetting the mixture is probably not necessary but there
is no harm in having a tune-up while you're at it. A reading
of about 3.5 to 4% CO should be achievable on a normal
engine assuming you haven't got all that U.S. type
emissions gear on it.
The earliest experiment I remember in Triumph circles
was a 2000/2.5 Register member who, apparently as an
experiment for the benefit of the rest of us, fuelled up with
the low octane unleaded, made no other alterations, not
even to the timing, and ran his car intensively. As a
consequence one of the pistons melted and, on the basis
of this one experiment (obviously a good scientist),
proclaimed that we should not use unleaded fuel at any
price!
Phil
TSSC 13/60 Secretary
Phil Willson
Electronic Engineering Dept
Queen Mary and Westfield College
Mile End Road
London E1 4NS
UK
Tel: +44 (0)171 975 5338
Fax: +44 (0)181 981 0259
email: p.j.willson@qmw.ac.uk
|