Hey everybody. New guy here after years of occasional browsing. Had my share of trucks and am perplexed by a few things on the 84 F250/460/C6 I just acquired. The rubber vac line the PCV valve uses also has whats looks like a small ball valve in line as well. It appears only partially open based off the handle if you will. Whats its purpose? is it supposed to be open 100% or?
Thanks all, hopefully I can offer something here and there based off the 35 years of wrenchin on old trucks and toys.

 

That ball is meant to take pressure away from valve covers and put it back into your intake or carb, or wherever it's hooked up to. If that ball were open all the way, I believe your valve covers would explode.

 

Ball valve? Can you get us a picture?
Sounds like something that has been added, there never was anything like that on my 86.

 

I say ball valve for lack of a better term. its in line, if I recall it has a squre or octagonal body,definatley factory and crust like the rest of the smog stuff ,has a lever like a ball valve and when the handle is in line with the pipe or hose its open, wne its 90% of the hose its closed. Ive had a few other Fords with this but never ask what the heck its intent was. I ask now cause Im curious and its runs poorly crusin on the freeway so im eliminating one item at a time. I'll take a pic and post up.
Thanks all.

 

I have never seen or heard of anything like this.

Subscribing just because I'm interested in what the heck it really is.

 

9B532 .. Compensator-Carburetor Hot Idle used on 1983/87 E/F250/350 460 (7.5L) only.

 

Heres what it is, Thank You NumberDummy, now I can sleep again .
When the ambient underhood temp increases to a certain point the bi-metalic strip on the hot idle compensator opens a rubber needle - brass seat metered orifice, causing what is essentially a vacuum leak of a predetermined amount into the intake system. This extra air will in turn cause the idle speed to increase, moving more air through the radiator and water through the cooling system due to increased fan and water pump speed the result being the motor will cool down to the point where the ambient underhood temp is lower, and the valve closes and the vacuum leak will stop, returning the engine to a normal idle speed. This cycle repeats itself over and over. Obviously this will only help during periods of engine idle . Remember, this was engineered in the early sixties and in theory is workable. What normally happened is that IF the little rubber needle valve did lift from the brass seat and cause the idle to increase, it sometimes would not seat properly when cooler, and caused an eratic idle. Most were tossed in the garbage back in the day. In the real word this little device probably caused more problems than it solved! It had a somewhat short life, was kind of a band-aid fix, and was replaced with a bigger and better cooling system as more and more Fords products were sold with factory AC. I do not remember the idle speed increasing in proportion to the temp.