PCV Valve

[TWISTER]

Do I need to run one?? Tell me what you think. 302 with Edlebrock fuel injection.

[TBS-POPS]

Re: PCV Valve

Yes if you are running any type of vacuum crankcase vent system.. It provides a check valve type of safety in the event of a backfire in the intake system. If your not using vacuum to extract the blowby gases from the crankcase and just have vent caps on the valve covers then no.

[TWISTER]

Re: PCV Valve

Yes, I was just going to run vent caps on the valve covers!

[jamesroney]

Re: PCV Valve

Uhm...why would you avoid a crankcase ventilator?

The purpose of the PCV valve is to maintain a slight vacuum in the crankcase to scavenge off any blow-by for combustion gasses that leak past the rings. This partially burned air/fuel/oil vapor migrates to the top of the engine, and collects in the valve covers, and the lifter galley.

The PCV valve bleeds off that vapor, and replaces it with fresh, clean air from the thing you call vent-caps.

If you do not have some means of venting the crankcase, it will of course eventually find a way to get out...by pressurizing the crankcase. Ford solved this on the SBF in 1963 by using a road draft tube mounted that funny trianglar shaped boss cast into the rear of the intake. The road draft tube takes the excess air/oil vapor, and directs it down past the transmission on to...the ROAD. It makes a huge mess, and it will lubricate your entire undercarriage.

The PCV valve sucks that excess vapor and pulls air IN from the vent caps. If you do not have a PCV valve, then the piston ring blow by will blow air OUT of the vent caps. That ends up messy.

Ford pulled the air out of the valve cover from 1967-85, then moved the location to the back of the intake manifold in 1986. (back where it started in 1963...)

Every vehicle produced after 1967 has a functioning Crankcase ventilation system. It works, and it has nothing to do with SMOG. Why would you ever remove it?

[TWISTER]

Re: PCV Valve

Good info!! Thanks.. The reason for removing it is I dont want it plumbed into the brake booster like it was, And im out of ports on the eddlebrock intake.. So If you have any sugestions I'm all ears.

[Fungus232]

Re: PCV Valve

PCV should be plumbed into a large port on the carb or EFI intake depending on what system you're runnin'. Brake booster is a whole other ball-o-wax!

[TBS-POPS]

Re: PCV Valve

Now we get all the info!!! the PCV should be plummed totally seperate from the brake booster line. The pvc system IS bennificial to the engine as Mr. Roney said and will keep things from getting messy. The brake booster should be plummed into full manifold vacumm totally by its self. Maybe a pic of your setup would help us see your choices.

[TWISTER]

Re: PCV Valve

Jeff, I figured it out. Just gotta go buy a inverter!!

[jamesroney]

Re: PCV Valve

With your set-up,if there is no port on the throttle body...I would recommend a throttle body spacer, with an integral vacuum tap. It would sandwich between your throttle body and the intake manifold. Should be able to get one from the local parts supplier, in the carburetor spacer section.

As mentioned...you want the PCV as far away from the brake booster tap as possible. The PCV is a built in vacuum leak, so your booster will never get full vacuum if it is tapped near the PCV port.

On a separate note...how do you like the ProFlo system? I was thinking of going with that system on my 67 Mustang...

[TWISTER]

Re: PCV Valve

I found a plug on the back side of the intake manifold im going to use. I love the Pro-flo system it has never let me down.