Dick et al,
The only emissions systems remaining on my 74 TR6 are
the crankcase vapor, fuel tank vapor, and anti-run-on
valve systems. The original owner removed everything
associated with the thermostatic vacuum switch as well
as the EGR valve.
The vacuum retard on my distributor is now directly
connected to the lower manifold connection by the
front carb. The small hoses from the top right of each
carb that would connect to the thermostatic switch (I
think) are connected to each other.
My question: without the thermostatic vacuum switch,
is the vacuum retard really "doing" anything at all,
or should I completely disconnect/plug it and then set
the dynamic idle timing to 12 (or 10?) BTDC?
Thanks,
William
'74 TR6
--- Sally or Dick Taylor <tr6taylor@webtv.net> wrote:
> William---Let's do the easy things first, here. We
> know that running
> with the ignition timing set at 4 deg. at idle will
> make the engine run
> hot when idling. However, there should be a
> temperature compensator in
> the radiator hose that interrupts the vacuum to the
> distributor retard
> line. This should kick in and advance the timing,
> which also raises the
> idle speed to about 1300 rpm. If your car is not
> equipped with this
> feature, it is better to set the idle timing to 12
> deg. B-TDC.
>
> It does sound like you also have a lean mix.
> Possibly the carb you
> suspect as having a "stuck" float needle valve is
> the culprit.
>
> It's been too long ago since all of my vacuum lines
> were connected, but
> I do recall if the engine were to slow down too far,
> the (red) ignition
> light would glow. This, coupled with low oil
> pressure might send a
> signal to the anti-run-on valve to apply vacuum to
> the carbs, and finish
> shutting down the engine.
>
> I'd retest the car after checking the routing of the
> emission control
> vacuum lines for your '74 and resetting the ign.
> timing, if necessary.
> Process of elimination.
>
> It doesn't sound as if the Pertronics is involved.
>
> Dick
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