Re: Jet hot and rev limiting rotor arms.

[paul.heneghan@bbc.co.uk (Paul Heneghan)]

From: gnt@nhm.ac.uk (Graham Thackrah)

> the replacement rotor arm for my 80 sport is going to cost me =A31=6.
>It is a roundish looking one and apparrently acts as a rev limiter. I have 
a
>rotor arm from Halfords (=A32.75 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?

Hello Graham.  Could you use GBP (or UKP) instead of whatever symbol is 
causing =A3?

The rev limiters in my Audis are in the rotor arm (some Audis cut off the 
fuel pump using a clever relay or ECU).  The rotor arm has a weight on a 
spring.  When the revs exceed a certain value (6800?), the centrifugal force 
on the weight overcomes the spring and the weight moves and shorts out the 
EHT, killing the spark.  Result - instant limiting of speed.

>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.

I've also got some rust spots that need treatment - they seem to be surface 
only, except for a deep one underneath the rubber surround to the 
windscreen.

Paul
paul.heneghan@bbc.co.uk
1984 Audi 80 quattro
1989 Audi 100 Avant