PCV Setup Question

[BulldogBronco]

I've had some issues with my PCV system and was curious about some of the ways to set it up. On the right valve cover if you are standing at the hood, I have the PCV valve going into the front of my Holley Sniper. On the left valve cover, I have the Oil Cap with a hose going into the air filter/breather set up. My question is, can I use one of the oil caps with the filter built in on top of it or does it need to flow into the air cleaner? The hose keeps pulling off the oil cap while I drive so I'm looking for alternative solutions.

 

[Broncobowsher]

A filtered cap works. That is the traditional hotrod setup. Open element air filter for the carb, filtered fill cap, PCV on the other valve cover. The 289 hi-po was that way from the factory.

The factory setup is better for emissions. excess blowby at high loads will go out the filter. Going into the air cleaner housing to be burned in the engine. Now why are you blowing the cap off? is the engine making too much crankcase pressure and blowing it off?

Another little thing, the front port on the sniper isn't the right place for PCV, the rear is. That front port (came from the factory with a plug in it) goes to the MAP sensor. There is a way to plug the internal passage to the MAP and use that port for a remote sense of MAP, this would be for things like a blower where the actual manifold pressure is not what is found at the base of the throttle body.

 

[71broncman]

A cap that filters the air works fine. That's the way I have both my Bronco and 75 F250.
Mark.

 

[BulldogBronco]

A filtered cap works. That is the traditional hotrod setup. Open element air filter for the carb, filtered fill cap, PCV on the other valve cover. The 289 hi-po was that way from the factory.

The factory setup is better for emissions. excess blowby at high loads will go out the filter. Going into the air cleaner housing to be burned in the engine. Now why are you blowing the cap off? is the engine making too much crankcase pressure and blowing it off?

Another little thing, the front port on the sniper isn't the right place for PCV, the rear is. That front port (came from the factory with a plug in it) goes to the MAP sensor. There is a way to plug the internal passage to the MAP and use that port for a remote sense of MAP, this would be for things like a blower where the actual manifold pressure is not what is found at the base of the throttle body.

Great to know, I did not know that! OK, then I need to change the whole set up. I will most likely move the PCV Valve to the passenger side and find a vacuum at the back of the Sniper. Do you know much about where the best place on the back would be to put the PCV valve to? I have the hydroboost brake booster back there too and obviously don't want to route into that.

 

[BulldogBronco]

And do you think I messed anything up by having it go to the MAP sensor? I haven't driven it much, I would guess 100 miles or less.

 

[Steve83]

This caption explains how the PCV system works:


(phone app link)

The hose might be too short, or the engine mounts might be broken, resulting in the cap coming off.

Hydroboost has no vacuum hose. Post pics:
http://www.supermotors.net/forums/thid-5972-how-do-i-post-pictures-sounds-and-or-videos

 

[BulldogBronco]

For the brakes, I said Hydroboost, I misspoke there. I have the Toms Bronco Parts disc brake conversion and I believe there is vacuum for that setup?

 

[SHX669]

It doesn't matter which valve cover but the PCV on one side and the filtered breather on the other .
Find a good constant vacuum source to connect the hose to .
After you're done and in the future an easy way to check that the PCV is operating correctly is with the motor running pull the PCV from the grommet it's plugged into , leave the hose attached and then put your finger over the PCV opening . There should be good suction and the " check valve " in the PCV should move freely when you remove your finger.

 

[DirtDonk]

Sorry to add a currently unneeded detail, but if you're ever working on, or building up an engine that uses factory EFI (SEFI instead of a throttle body) you will need to plumb the PCV's filtered air return into the area behind the MAF and cannot use just a filtered cap like you can do on yours.
On this type of setup, the air is officially metered through the system so that the computer knows how to adjust. With your TBI you don't need to worry about that, but I figure just in case you're ever working on another type of system you'll know that.

Paul

 

[BulldogBronco]

Thanks Paul and everyone else! I went and adjusted some stuff over lunch and have a filtered oil cap ordered as well!