It was commented:
> When I removed the fuel bowl overflow tubes from the air cleaner and
> rerouted them to the ground, I redirected the PCV tube to where the fuel
> tubes used to go in the air cleaner.
On the '70 model year, for evaporative control reasons, the vents on
the fuel float bowls were routed into the air cleaner instead of venting
to atmosphere. A side benefit is that only filtered air is supplied to
the bowls.
The attach points on the air cleaner are neutral pressure - that is, they
provide no vacuum draw (assuming a clean air filter :-) ). IMHO, this
routing has no detrimental effect on performance, and possibly a
negligible improvement for the air we all breathe.
The PCV fitting in the middle is different. Assuming there's still
the rubber 'tee' inside the housing, this fitting does run at a vacuum.
There are venturi tubes in each internal airhorn, and the air flow
thru the carbs creates a slight draw to help keep the crankcase
ventilated.
Unfortunately, excessive oil thru the PCV line means excessive
blowby in the crankcase. Plugging or rerouting the line may hide
the symptom but it doesn't fix the problem.
-- John
John F Sandhoff sandhoff@csus.edu Sacramento, CA
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