1. The vent relieves pressure in the head from gasses in the combustion chamber. It helps to keep oil from blowing by the valve cover gasket.

2. You also have a PCV (Positive Crankcase Ventillation) system. That is the hose going from the drivers side of the engine over to an inlet on the intake manifold. It is supposed to allow negative pressure (vacuum) in the intake manifold to draw volitile gasses out of the crank case. If gasses are to come out of the crank case, then something must replace it to avoid making a vacuum. Filtered air is supposed to come in via the hose attached to the oil cap.

I had a problem with condensation collecting in the hose fitting below the air filter. I tried taking off the intermediate piece (the plenum between the air filter and carburetor) and just using a little PCV filter directly on top of the valve cover cap. The filter allowed oil to spray out under heavy loads. It was great for saturating the engine compartment and anywhere I parked with a nice coat of hot oil.

Now that the weather is warmer condensation isn't a concern. The factory set up was reinstalled and all is well. Hopefully a solution to the condensation problem will present itself before next winter.

You really should not defeat the purpose of the vented oil filler cap. Please explain about your hose not staying on. Is the hose long enough? Are there hose clamps securing it in place?

Best regards,

Joe M