Trevor Jordan wrote:
>Can anyone explain the operation of the thermostatic vacuum switch on post
>1972 TR6s? I have heard it described as an anti-run on valve, but there is
>no connection to the ignition, so how would that work?
The anti run-on valve is to the right of the radiator beneath the vapor
canister. And, as far as the anti run-on valve goes, I can tell you
(although you didn't ask!) that it doesn't work very well! (he, he!)
>As far as I can tell, the valve switches the vacuum to the distributor (TRF
>vol 1, page 99). Presumably this disables (or perhaps enables) the vacuum
>advance until the engine is hot. This looks like a method of improving the
>exhaust gases from a cold engine and should have no effect when a hot
>engine is shut down. It may also be there to improve cold starting.
Yes, I know you're on to something here, but remember that it is the vacuum
RETARD, not ADVANCE. There is no vacuum advance on a post '72 TR6. I'm
not clear on whether it switches vacuum to the retard unit ON when cold, or
OFF when cold. Someone else will have to field that one, 'cuz I just don't
know.
>In the case of the post 1974 TR6s (TRF vol 1, page 100), there are even
>more vacuum lines from the valve. They connect to the top of the carbs; I
>have no idea what they do.
Can't explain why there would be MORE vacuum lines here either. But that's
what they do... carry "vacuum." ;^)
OK, so I'm a smart-ass!!
Pete Chadwell
1973 TR6
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