Jet hot and rev limiting rotor arms.

[gnt@nhm.ac.uk (Graham Thackrah)]

Dear List,

What is Jet Hot and why do exhaust manifolds and downpipes benefit from
treatment with it?

Secondly, the replacement rotor arm for my 80 sport is going to cost me £16.
It is a roundish looking one and apparrently acts as a rev limiter. I have a
rotor arm from Halfords (£2.75 odd and rectangular in plan view) which will
fit as well but doesn't limit revs. has anyone else come across this and
replaced with either the rev limiting arm or alternative? I have already
decided to replace with the limiting one but would be interested to know how
it works. You can rotate the present arm backwards opposing its usual
direction of rotation, this I assume is to alter the timing at high revs
(actuated by a vacuum tube) but is it anything to do with limiting the revs?

I had planned to tackle some rust spots this weekend but as the UK listers
are aware the climatic conditions prevailing are far from suitable, any smug
comments from California ungratefully received.

Cheers 

Graham.
'85 80 sport.