Posted by Bob
on 8/26/2008, 8:50 am, in reply to "Re: Crankcase Ventilation Problem"
74.74.77.70
I'm using the same carburetor. You are correct to say that the PCV valve is a controlled vacuum leak. When you first hook it up and start the motor, the engine will idle 50 or 100 rpm faster, just like if you had an open vacuum line. Readjusting the idle speed closes the throttle plate a little and reduces the volume of air going into the engine to the original amount. I didn't have to make a significant change to the idle mixture.
--Previous Message--
: Bob:
:
: I don't have an answer to your
: question, but I have a question for
: you: did you use the same carb, or
: did you change the carb to a later
: one that was designed for use with a
: PCV? The reason I ask - the PCV is
: really a "controlled vacuum
: leak", and I always assumed
: that if you added a PCV and tried to
: run it with a non-PCV carb, it would
: run lean.
:
: I was contemplating doing the same
: thing you did. Maybe you can fill me
: in on that detail.
:
: Thanks,
:
: Jim
:
: --Previous Message--
: I have a 1962 Falcon station wagon
: with the 170 motor. It has about
: 134,000 miles on it. It has a draft
: tube to ventilate the crankcase.
: When the engine is idling, the fumes
: from the crankcase vapors drift out
: from under the car and are picked up
: by the heater in the cooler weather.
: When it is parked in the garage, the
: convection flow of air up through
: the draft tube and out the oil
: filler cap fills the garage with
: noxious gas odors. In an attempt to
: eliminate both of these problems, I
: decided to install a PCV valve. I
: purchased a valve cover with a PCV
: hole from Auto Krafters and
: installed it this weekend. I
: purchased a Mr. Gasket oil filler
: cap with a foam filter insert, and a
: new PCV valve from Carquest. I
: attached a 3/8 inch hose to the PCV
: valve and connected it to manifold
: vacuum through the aluminum adapter
: under the carburetor. I also plugged
: the draft tube to prevent outside
: air from flowing into it. With the
: engine idling, there is a slight
: vacuum at the oil filler cap and no
: vapors escape. However, if I put the
: car in Drive with the emergency
: brake set and then briefly rev the
: motor, crankcase vapors begin to
: flow out from the oil filler cap, so
: the PCV valve apparently cannot pass
: enough of the vapors to keep them
: from escaping. Looks like there is a
: lot of blow-by from the piston
: rings. I thought that I might be
: able to use a PCV valve from a 200
: or 240 cube engine, thinking that
: they might pass more vapor. However,
: the parts catalogs indicate that all
: of the six cylinder motors use the
: same PCV valve. Short of an
: overhaul, is there any way that I
: can solve this problem? Thanks for
: any and all ideas.
:
: Bob
:
:
:
Message Thread:
« Back to thread