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Smooth idle and vacuum leaks (long)

To: <6pack@autox.team.net>
Subject: Smooth idle and vacuum leaks (long)
From: "Navarrette, Vance" <vance.navarrette@intel.com>
Date: Wed, 12 May 2004 08:29:53 -0700
    Folks:

        Spent some additional time this weekend working on the 6, my
favorite thing to do =:-).

        I got the speedometer working, and discovered yet another brain
lapse on my part.
After I installed the OD, the speedo never worked. Verified the speedo
was good, the
cable wasn't broken, and finally concluded that the output on the OD
either was not
turning, or it was not engaging the cable.
        Well, to make a long story short, when I had installed the OD, I
had removed the
speedo drive gear from the OD speedo output shaft, and pressed it onto
my 4 speed
speedo output shaft. The shaft was too long to fit the J-type OD, so I
took my
trusty dremel and shortened it. It looked very professional. Just one
problem;
the internal splines that engage the speedo cable only extend about
1/4", so when
I shortened the shaft, I cut off the splines. The shaft would turn, but
there was
nothing gripping the end of the cable. Doh!
    A quick trip to my LBC mechanic's shop yielded a new shaft of the
appropriate
length which got the correct gear pressed onto it in my vise. Voila!
problem
solved.
    Ahem. Now to the matter in the subject line.
    After buttoning up the speedo work, I proceeded to install my new
vacuum retard
capsule and set the timing an idle. As I had noted previously, I seemed
to have
a vacuum leak coming in through my carbon canister, so I had blocked the
line
between the canister and the carb mixing chambers to obtain a smooth
idle (well,
as smooth as I can get with the new cam). I decided to locate and fix
that leak.
    I have verified that with that line blocked, I get a smooth idle,
and with the
line connected to the canister the car stumbles and eventually dies.
    Best I can tell, however, the canister is open to atmosphere by
virtue of the
anti-run-on valve, which vents the canister. So, it is *SUPPOSED* to
leak. Hmm.
So what do I do now?
    Am I missing something? Perhaps there is supposed to be a
restrictor, or maybe
this is the wrong canister (not the original). It has the three nipples
on
top, and one on the bottom side. It says COOPERS on it. Looks OK. But
the large
nipple is 5/16" or so in size, and so represents an unrestricted leak
from the
canister to the carbs via the vent hose. My car is a 74-1/2, with all
emissions
stuff in place. 9.6:1 CR, 270 degree cam, stock exhaust and carbs.
Timing is
12 BTDC static.
    Perhaps with the new cam, the car will not tolerate that much air
flow into
the carbs? Wrong canister? Missing restrictor? *WHAT*?
    Any insights out there, oh grand poobahs of TR6-dom? I await your
wise
counsel.

        Thanks,

        Vance





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