Mike,
I read Dick's reply and wonder if the vacuum lines to the thermo switch
could be hooked up "backwards?
----- Original Message -----
From: "Sally or Dick Taylor" <tr6taylor@webtv.net>
To: <DaCRANEz@aol.com>
Cc: <6pack@autox.team.net>
Sent: Monday, May 03, 2004 8:36 PM
Subject: Re: vacuum retard
> Mike C.----I can't tell you if or where you might have the vacuum leak
> that you suspect. There are a couple of points that have been offered to
> you that is open for debate.
> Meanwhile, you should have vacuum present at the retard capsule, at idle
> speeds only, IF the vacuum line is connected to a port on the carburetor
> downstream of a closed throttle plate.
> If you have no vacuum present at the distributor, follow this line back
> to its source. A functioning retard will change the timing by as much as
> 16 deg. (i.e.12 deg. BTDC to 4 deg. ATDC) and slow the engine down
> approx. 500 rpm.
> Conversely, if your engine speed has been set by carb adjustment only,
> with no vacuum retard in operation, there will be no change in speed if
> you pull this line off the retard capsule.
>
> I haven't ran with the thermostatic switch in the top hose for some time
> now, so I'm not up to speed on how this works, entirely. I do remember
> at when the coolant got to a certain temperature, the switch would
> interrupt this vacuum, and cancel the retard. We know this interruption
> of retard speeds up the engine by allowing the timing to increase by
> several hundred rpm.
> Here's what I'm not so sure about...If it is necessary for the coolant
> to get up to a certain (normal running) temperature before the switch
> opens up the retard line, this would cause the engine to idle much
> faster than normal, as the coolant is warming up. (Just as if the retard
> was canceled by coolant being too hot) I don't remember this ever
> happening. Once the Choke knob was pushed home, the engine speed would
> idle around 800 or so, even with the gauge reading about 120 deg.
>
> So, based on old memories and what I believe should happen, the only
> purpose of the thermostatic switch is to cancel the vacuum retard during
> times when the engine was idling, and too hot. I welcome discussion
> from those who find it differently.
>
> Dick
|