Roger Bolick sent me valuable information on tuning ZS carburetors, and I
was able to seal several vacuum leaks and dramatically improve the
performance of my TR6 with the fresh motor. Thanks, Roger!
But, the quieter, smoother running condition has allowed me to detect
another problem. There is syncopated "pht pht pht pht" under the hood
and corresponding stumble in the exhaust at idle. This sounds to me
like a leaky intake manifold gasket. That's not surprising, because I
made it myself.
I have a set of Weber carbs that I'll be installing after the motor is
run in, and I enlarged the intake head ports to give a better match with
the Weber manifold. This made the stock gasket worthless, so I bought
some gasket material from the local machine shop and made my own. The
material is copper mesh, clad with some tough black stuff. This
material was very difficult to work with. After experimenting with some
small bits of it, I settled on cutting it with a sharp chisel against a
wood board. This method gave fairly good accuracy in cutting out the
ports, but it left the copper wavy and, in some places, knotted. I
cleaned it up the best I could, but apparently not well enough. So now
I assume there are leaks.
Can anyone recommend some other types of material for creating a
suitable gasket? The gasket is shared by the intake manifold and
exhaust header, so it must be quite tough and durable. Ideally,
however, I'd like a material that is easier to cut accurately than the
copper mesh I have.
Alternatively, can anyone recommend a better method of cutting the
material I have?
Also, cast-iron brackets are used on this car to clamp both the intake
manifold and the exhaust header with a single bolt. With the stock
intake and exhaust manifolds, this system worked adequately. But I
currently have a header, and the mounting flange is not the same
thickness as the intake manifold---soon I'll have yet a different intake
manifold, as well---so I'm looking for a more positive method of
securing the two flanges, using a common stud, but with something other
than the stock cast-iron bracket. Do any of you have experience with
this, or do you care to offer creative suggestions?
To finish the story, though, the car is really beginning to run well,
now. It's faster than it's ever been before. And I still have not
rediscovered the klunk in the rear :^)!
Kevin Riggs
(205) 730-3074
work@riggs.b30.ingr.com
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