Hey, all. In a small discussion on the Bird board, I realized that neither Brad Anders nor I were sure how the PCV system on the 75-76 cars worked. I know that in at least some cases the hose from the oil filler hooked directly to the air cleaner, as opposed to the manifold like in the 70-74 cars. I think that there may not have been a valve in those cases. I also think those were the same cars that did not have the vents into the rocker boxes.

I would like to get confirmation on the setups for the late cars. There originally would have been a booklet that came with the car describing the smog systems (the one for my 74 talks about the PCV, complete with a diagram of how the air "should" flow) that came with the car. Owner experience would be a good guide as well--were there CA vs. 49-state differences? The "year-to-year changes" factory document would also come in handy.

I think I have some of these resources at home, but I am not sure where they all are.

Anyway, can someone shed some light on this for us?

--DD

I'm looking forward to this. My '75 does not have a PCV valve. A vent hose next to the oil filler connects to the intake above the butterfly.

I don't know if that's stock or not, but I've been unable to get solid facts on whether it should have a PCV valve or not.

1.) No rocker box vents

2.) No PCV valve....Oil filler vent hooked to air cleaner (vent is a straight hole).

3.) Can't tell you if they are CA only or Federal (49 State). I just have the engines. (Oh sorry, they are 2.0L)

My late model is the same setup. I had searched here and the PP forums trying to determine if this is correct of if a PO left off the PCV valve. I came to the conclusion this is correct. What's a rocker box vent? My car was originally from Cali.

70-74 cars had head/valve cover area vents, right by the intake manifolds.

I believe that's just a vent in the valve cover (with hose that Ts into the oil vent to intake line).

As far as I know none of the late model cars had these, but some people have added them. Another area of debate and confusion, but I don't think it helps enough to be worth adding if they didn't come with it.

The rocker box vents in the heads (rocker box = where the rockers are encased not the rocker box cover) are connected by hoses to an "anti-flashback valve" which is connected to the air cleaner.

The anti-flashback valve sits on the driver's side, attached to the impeller housing by a cheese-head screw.

Dave,
EGR's were only on the CA cars for '75/'76 according to the workshop manual. Section 2 (my supplements) All other states did not have it. Same with the CAT.

Don

Hi Dave,

Just to add to statistics. 1976 2.0L Cali car :

* No rocker box (valve cover) vents.
* Hose from Oel filler area to intake mf, before butterfly, no PCV valve
* Used to have smog pump system