Jack Drews wrote:
>My newly purchased TR6 diesels after being shut off. I know this is
>because something in the combustion chamber is too hot and glowing and
>shouldn't be. Before I remove the head and decoke it, is there any
>chronic cause for this in TR6's?
>
>Additional info: The engine has 46,000 miles on it, compression 150 on
>all cylinders, plugs look normal, car has never had the head off to my
>knowledge, and since it doesn't have hard seats the previous owner added
>a lead supplement to the gas (maybe this formed some deposits).
>
>If I can fix it without removing the head I'd like to, but if I remove
>the head I'll have hard seats installed.
There are definitely more qualified people on this list than me, and
hopefully they'll chime it too. But, my understanding is that although
build-up of carbon in the combustion chambers COULD cause the run-on, it is
by no means the only cause possible. Ignition timing and idle speed have a
big influence on this, and if I can reach a little bit, I suppose if the
cooling system were running a little too hot that may encourage it a bit as
well. Someone correct me on this.
My TR6 deisels a bit from time to time... not real frequently, though. And
I rebuilt the engine about 35-40000 miles ago. I use the clutch to prevent
the odd run-on by letting the pedal out (in gear) as the engine shuts down.
Keep in mind that I don't DUMP the clutch to KILL the motor... I let the
switch do that... but just when the motor stops turning I "put the brakes"
on any deiseling by engaging the clutch.
Anyway, if your idle speed is too high, (as mine is) then this is a big
influence on deiseling as I understand it.
Good luck,
Pete Chadwell
1973 TR6
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