[Fot] Distributor Retard

[Larry Young]

If they only wanted it retarded at idle, there would be simpler ways to 
do it. My TR250 had a little valve which activated the vacuum retard 
with the throttle linkage.  Why make it vacuum dependent? Are we saying 
Triumph made these cars unnecessarily complicated, i.e. like a German 
car?   - Larry

On 1/12/2014 4:20 PM, Randall wrote:
>> This is not a racing question.  I'm sure the ignition retard is often
>> disabled on 6 cylinder Triumphs.  Does anyone know why it was used in
>> the first place?  I have always thought it was strictly for
>> emissions,
>> which became more restrictive in 1968.
> Supposedly it raises cylinder pressure at idle (by allowing the throttle to be open farther at idle), and hence promotes more
> complete combustion, reducing HC emissions.
>
>>   Perhaps it improves
>> combustion
>> at low throttle such as when decelerating or when descending a hill.
> That would be the throttle bypass valve, which effectively opens the throttle even further (for the same reason).  Other cars used a
> gulp valve, I'm not sure why the difference.
>
> Randall