Carb Manifold Pipes

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500 Dino
Posts: 19
Joined: Thu Aug 03, 2017 1:41 pm
Dino: Fiat Dino 2.0 Coupe

Carb Manifold Pipes

Post by 500 Dino »

Evening chaps,

Just getting my 2 lt Coupe tuned up on a rolling road, seems I need my spindle bushes replacing on the DCNFs, as there is an air leak there. My mechanics are also confused about the 2 pipe connectors on the carb inlet manifolds. I do not have the original air filter assembly but a K&N style filter box for each carb. This has been working fine but the mechanics say that the 2 pipes should not just go into these air filter boxes; "surely the pipes are for a vacuum..etc"
Looking at the diagram attached, I would say not. It looks as if they are just supposed to join the oil filler vent pipes as they enter the standard air filter.
Is this correct?
My mechanisms have currently closed the 2 fittings off, so making them air tight. This does not seem right to me.

Can I have some advice please?

all the best
Graham
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Stefan2000
Posts: 167
Joined: Sat Feb 21, 2015 8:42 am
Dino: Fiat Dino 2.0 Coupe
Location: The Netherlands
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Re: Carb Manifold Pipes

Post by Stefan2000 »

Normally they are open and with a hose attached to the air filter.
The reason for these tubes are the following:
Blow by gasses enter the airfilter thru the oil filler vent pipes. Without these tubes the blow by gasses would go thru the carburettor into the engine. It would actually go thru the idle circuit of your carburettor and that is a circuit with some very fine and small holes. This is off course not ideal and that's why these tubes are there. They redirect the blow by gasses into the engine so that it will not go thru the carburettor.
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