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[me96jvb]

Does anyone know what the function is of the 3mm dia drillings that can be seen in each of the 'manifold' castings that bolt on top of the carbs on a 1.7 8v Cloverleaf.

Each drilling starts at the face of the casting where it attaches to the (rectangular) airbox and exits inside the runner, halfway down. There are 4 holes in total - one per runner (ie 2 per casting).

I can't think what function they possibly perform! Anyone know?

JB
(Alfa 33 1.7 8v - engine in bits!)

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[lesthegringo]

I think that the holes are there to allow the carburettor float chamber to 'see' the same atmospheric pressure as the carb chokes.

If the filter was blocked, or restrictive, then there would be lower pressure in the intake system above the throttle butterfly, and if the float chamber was at the higher ambient pressure, it would push fuel through the drillings in the carb to the choke, rather that the air rushing past sucking it - it would make the mixture richer than necessary. It could also result in the fuel level in the float chamber being wrong, so the emulsion tube would not work how it was supposed to.

Just some thoughts.... I may be wrong though!

Les