Two PCV systems on a 62?

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Spook50

Spook50

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While looking at my engine, I noticed that there seems to be two PCV systems going from the valve cover to the intake. The main one in the back with the PCV valve, and then another without a valve that connects to the intake duct itself. What's the deal with this extra one, and any guesses as to why it wouldn't have a valve on it? It definately offloads a fair amount of crap into the intake and fouls up the throttle body something aweful.
 
Hey Spook, My rig and FSM are in AZ and I'm in NM so I can't be sure but I think I know the little section of hose you are talking about - I think it is a vent hose for the a/c. In any even I believe it is on other cruiser engines and not just the 3fe. Now you have me curoius I going to have to check it out when I get home.
 
Yes, there's also a ventilation hose which from just behind of motor oil filler cap.

Oh, Min Seok
 
schaats said:
Yes, there's also a ventilation hose which from just behind of motor oil filler cap.

Oh, Min Seok
Click to expand...

Yeah that's the one I'm talking about. Doesn't that kind of negate the whole purpose of having a valve on the actual PCV line? I would think this forward vent could easily be eliminated...
 
one is an inlet
 
CruisinGA said:
one is where fresh air enters the system, the other (with the PCV valve) is where it exits.

Note one is under vacuum (PCV valve) and one is not.
Click to expand...

Wouldn't the forward hose also be under vacuum since it's plumbed into the intake duct? I have noticed a good amount of nasty crud built up in my intake duct from that connection.
 
There is very little vacuum in the intake duct, just the resistance that is generated by the air filter and air box ducts etc, the pressure really drops at the throttle plate,

If you have a lot of crud coming out of the inlet side you either have a plugged or partially plugged PCV that is not taking out all of the blow by or you have excessive blow by that cannot be handled by the PCV system so the excess travels in reverse out the inlet.

Read more

http://www.autoshop101.com/forms/h63.pdf
 
RavenTai said:
There is very little vacuum in the intake duct, just the resistance that is generated by the air filter and air box ducts etc, the pressure really drops at the throttle plate,

If you have a lot of crud coming out of the inlet side you either have a plugged or partially plugged PCV that is not taking out all of the blow by or you have excessive blow by that cannot be handled by the PCV system so the excess travels in reverse out the inlet.

Read more

http://www.autoshop101.com/forms/h63.pdf
Click to expand...

Wow, good read. Thanks for the link. I'll try to pick up a new PCV valve next week (with grommet) to see if I can alleviate the rate of buildup in my intake. It never would've occured to me, since the valve is somewhat new (put it on towards the end of last summer I think). Hopefully soon I'll be able to pull off my TB and give it a good hardcore cleaning too, and see if that'll help improve anything.
 
do you think the crud could be old? possbily from before the PCV valve changed?
 
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