> Having restored the car to running and driving status with the help of
> the list (thank you) I now find that the car runs on and knocks roughly
> after turning off the ignition. I remember this being called "dieseling"
> and attributed it to carbon buildup in the heads causing ignition
> without a spark. Is this correct? What can or should be done about it? I
> stop this by engaging the clutch with the car in gear but worry about
> the long tern effects. Any suggestions?
Richard, all of my TR3As have run-on occasionally, so I've made a habit of
always killing the engine with the clutch just as it dies. It doesn't seem
to have had any long-term ill effects, except some occasional surprised
looks from my passengers.
To me, it seems like modern fuel, plus higher under-hood temperatures, are
the reason it's more of a problem today than it was in the 50s. Making sure
the idle rpm is down to factory specs (using an accurate tachometer, the one
in the dash is likely no longer accurate); and setting the mixture just
slightly to the lean side (1/2 to 1 flat leaner than the "ideal" position
given by the lift the piston test) will help too, but in my experience will
not completely eliminate the problem.
I've not tried it yet, but I would guess that the combustion chamber
modifications outlined by Kas Kastner in the factory competition preparation
manual, would help too. He mentions getting rid of all the sharp edges in
the combustion chamber.
Another way to look at it ... these engines just love to run. Given the
slightest excuse, they will continue doing so even without the ignition !
Randall
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