Here's a good one. My #2 64 Valiant V-200 225 6 w/ BBS carb is all orig. BUT the "Super 225" air inlet has me bewildered.

Besides the PCV valve (going to the carb), the oil fill cap also has a vent tube going to the air filter. Two negatives make a positive in math I know, but this seems like PCV over-kill. I shall swap, but has anyone else seen this gettup?

I believe the car was made in late 63, but it still seems weird.

cole020@yahoo.com

My first Valiant had the same set up on its 225 and if I remember the pvc goes to the base of the carb. and gets clean manifold vacuum while the oil vent line that goes to the air cleaner gets less of a vacuum since the butterfly is between the two of them in the Carb.
It does look the same but there's a fine line of difference in vacuum I believe.
Good luck...

You didn't mention the your Valiant's vintage.

I understand there would be a difference in vacuum due to the pressure drop across the b-fly; thereby giving one side preeminence depending on the choke & throttle position. But was this vehicle designed to have a "closed" PCV system? Should I worry about sludge, since there is no fresh air induction.

I have never seen another 63-65 Valiant with this setup and both the Owner's Manual & 64 Service Manual show the "open" PCV system, so I wonder how original it really is.

I can't speak for all cars but most have this set-up. The PCV causes a vacuum in the crank case so air is allowed to enter back in to the crank case through a vent (sometimes the filler cap serves double duty). The reason for the hose being connected to air cleaner is so the make up air is filtered. Some setups take the air from the down stream side of the filter (ie. connected to the base), others from inside the housing with it's own little filter. Nothing magical,just the manufacturers trying to keep the engine internals a little cleaner.

Mine was a 65 4 door with a 225 and 3 speed that I
rebuilt the engine on in 1978 and later in 1981 sold. My current 65 valiant has a 273 in it.
I remember the PCV valve piped to the base of the carb. and the vent hose from the oil filler cap going to the housing on the air filter. This might have been done this way for pollution control since the car was in California.
I would from time to time clean out the PCV valve and then make sure it works proper before putting it back in.
Boy do I miss that old slant six and the good time's it gave me...
Best of Luck...

Merganser: Your '64 has the "fully-closed" setup first used in '64 on California cars and expanded to nationwide usage in '68. The solution to your "negative/positive" puzzle is that there is suction only via the actual PCV hose that runs from the PCV valve to the base of the carburetor. But, under conditions of low or no manifold vacuum (wide open throttle) crankcase fumes don't get sucked into the manifold through the PCV valve. Instead, they force their way out of the crankcase vent. On the '61-'63 (California) '62-'67 (New York) '63-'67 (Nationwide) "semi-closed" system, the oil cap was bottom-vented directly to the outside atmosphere. Under these low-vacuum conditions, crankcase fumes went sailing out into the air. California wanted that NOT to happen, so they closed-off the bottom vents on the oil cap and instead ducted the crankcase vent to the *DIRTY* side of the air cleaner (OUTSIDE the element). That way, under high-vacuum normal conditions, air is taken in through that upper vent hose, cleaned of any dirt by the oil-wetted metal mesh inside the oil cap (just like the earlier system), swept through the crankcase, metered through the PCV valve, and sucked into the manifold. But under those low-vacuum conditions, crankcase fumes travel back UP the vent pipe, and get sucked through the air filter into the engine anyhow. This minimizes the escape of crankcase gases to the outside atmosphere.

It's really up to you whether to keep it or discard it. When engines with closed crankcase vents get old and worn, the volume of crankcase gases can quickly wet-down a paper air filter element with oil, clogging it. There are ways around this. Right, Doug?

DS

Good summary.

If the issue is that your "worn" engine / system promotes rapid oil "wetting" of the air filter, then you can either rebuild the engine, change to an "open" type system or make-up a "trap" to separate the oil mist from the vapor prior to it getting into the air cleaner. I have "cobbled up" many of these "oil separators" over the years, here's how:

I used a sealable can and have large hose fitting on the top and bottom. (I come in from the side.) I also have a "drain cock" or a hose barb fitting positioned at the lowest point of the can. I stuff the can full of coarse steel wool, seal it up and hook up the hoses. On some really worn engines, I run a small "drain back hose" from the bottom of the "separator" back into the engine, (to the dipstick or at the fuel pump, the ones with the vapor fitting on them). This setup collects the oil mist and automatically drains it back into the engine while you drive. It keeps the air filter dry and the "California air" clean(er?)
DD