Vance---Can't tell from here whether your vacuum leak can be fixed by
rerouting, or restricting. I can offer this:
Peformance cams, even the modest one you chose, like lots of fuel at
idle, and a good amount of timing advance. At least 8 deg. BTDC, tuned
dynamically. The need for a rich diet of fuel means it will not be
tolerate idling with any unmetered air entering the engine, as you
already know.
A vacuum gauge on the intake manifold should show a steady reading of 12
inches or better.
Since you have replaced the stock cam and increased the CR, we know it
will never be as "clean" as a stocker. You should now consider doing
away with the factory emissions recovery system. If you wish, you can
still route the fuel tank breather hose and the engine gasses into the
air intake. While it probably won't be as efficient as when operating
under the factory vacuum system, you can still dump these fumes back
into a running engine without upsetting the air/fuel mix.
This is better than letting it go to atmosphere, environmentally
speaking.
A quick way to tell if an engine isn't getting enough fuel, (or too much
air) is to restrict the carburetor air intake, by hand. If the engine
speeds up, or at least gets happier, the mix was too lean.
The same test can be made by partially opening or removing a working
vacuum line. In this case, if the engine speeds up, chances are the mix
was too rich.
Sounds like you're having fun, so carry on. Don't forget about the
thermo switch test!
Dick
Vance concluded,
.......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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