Proper PCV set up

[Ned]

I think I got some bad advice to simply run breathers on both sides. Any thoughts, pictures, advice. As far as I can tell in my search in this fourum most people are pro PCV set up for various reasons. My question is what is the best way to set up the system, I have read to put a breather on one side and a PCV valve set up going into the base of the carb. I have a holly 650 and an aftermarket aircleaner. Keep in mind the air cleaner does not have a set up on the botom of it for another tube as the stock one did. I am assuming that was the tube from the drivers side, but honestly I cant remember.
I could run the old air cleaner but I would have to install a spacer on the carb in order to clear the curent HEI Dist set up, and I really dont want to get into that right now since the studs on the Edelbrock intake are not that long and would have to be replaced to fit both the carb and spacer.

 

[blubuckaroo]

Is there a 1/8" pipe plug at the front of the throttle body of the carbureter? A nipple can be threaded into that spot for the PCV vacuum port.

 

[Broncobowsher]

Passenger side rear of the carb is usually a nice big nipple that works perfect for the PCV.

With your setup and description of parts...
Keep one filtered breather (usually drivers side front valve cover)
Change the other to PCV (usually passenger rear)
If the other way around works better, it is fine as well. All you are trying to do is establish a regulated flow of air through the engine. You don't have EFI so no issues with un-metered air from the breather.

 

[broncnaz]

The holley carb should have a port out the rear or pass side rear to connect a 3/8" hose to then you connect your PCV valve to the hose and install it in a oil fill cap that accepts PCV valves. Then you can either run a breather in the valve cover or a hose up to your filter they do sell adapters to fit aftermarket filter housings.
http://www.summitracing.com/search/...t-Type/Air-Filter-Assembly-Vents/?Ns=Rank|Asc
Most of the parts can be found at your local parts store.

 

[Broncobowsher]

You can get by with the picture above but use one of your existing filtered breathers instead of the hose off the air cleaner.

 

[Steve83]

http://www.fourdoorbronco.com/board/showthread.php?t=5427

 

[DirtDonk]

What air filter do you have? Many of the aftermarket filter housings have a couple of knockouts in the lower half (assuming typical round filter housing that is) that you can use with one of their fittings to run a hose to a nipple/elbow on the cover.

Paul

 

[gearida]

On my Harley, since there was no access to the carb, I drilled a hole in the bottom of the air cleaner and used a hollow tire valve stem for an access hole. It works fairly well.

 

[gumbydood]

The picture explains it well. You want to evacuate the crankcase of the blow by gases with vacuum, but you have to allow for filtered air to replace it. A one-way valve (PCV or positive crankcase ventilation) goes through a hose to a vacuum source, preferably one that provides equal distribution to all cylinders (the base of the carb as opposed to an individual intake runner). On the other side is a filtered source... either a filtered breather or a hose from inside the air filter.
PCV Systems are not necessary, as an engine will run perfectly fine without one. I can't think of any motorcycle that has a true pcv system... all I've ever seen have been crankcase vent lines that either run to the airbox or to the atmosphere. I do know that when I accidentally pinched the crankcase breather on my fzr400/600 it blew out the cam seal portion of the valve cover.

I'm putting a rebuilt 302 into my 71, and swapping in an edelbrock intake and carb. I've got a filtered breather that accepts pcv valves on the passenger side valve cover connected to the center nipple at the front of the carb and a filtered breather that does not accept pcv valves on the driver's side (front). I chose this to allow easier adding of oil, since my valve covers (and most, I believe) have the holes near the left end.

Eric aka Gumbydood

 

[4lofun]

what about a mustang 5.0. i have the pcv line going directly to upper intake manifold. i also have lean codes during engine running test. is this unmetered air making a lean condition??

 

[DirtDonk]

Should have the valve at the back of the manifold plumbed straight to the upper plenum, for full manifold vacuum. Sounds like that's how you have it.
What about the return line? Should be a line (no valve, just direct hose) from the valve cover with the oil-fill tube straight to the intake ducting, somewhere between the MAF and the Throttle Body.
Many of them (Ford EFI setups) have a hose nipple right in the TB just in front of the throttle plate. Others have a tube fitting (usually a 90° elbow) plumbed into the flexible plastic intake tube after the MAF sensor.

that how yours is hooked up?

Paul

 

[4lofun]

the return line goes from oil fill tube to throttle body 90 debgree fitting sounds like i have right. i gueess ing its the pcm needs programming for 24# injectors. larger maf. thanks for info dirtdonk

 

[DonsBolt]

with a holly, do this
pcv on the passenger valve cover
breather on the drivers side

 

[Ned]

Thanks, I think the set up I am going to go with is what DonsBolt showed in the pictures. That seems to be pretty close to how my engine is configured, of course, minus the trick vave covers and what looks to be a a super clean set up.

 

[Smokeater11]

I have had issues when I ran a breather on the DS puking oil out of it. I have my PCV set up as shown in the pics but have had to put a solid cap on the DS. My valve covers don't have any kind of baffle under the breather hole to block what I assume is oil slinging off the rocker arms. I might have to look into this since air flow through the DS seems to be needed. I had one of the dome shaped Edelbrock breathers and the oil would saturate the filter element and then drip out onto the valve covers and eventually onto the exhaust.

 

[DirtDonk]

Very common issue unfortunately. Even a fully filtered breather, like a K&N style, but especially the old type that merely had steel fiber mesh inside the cap, would ooze oil after a very short time.
You're right. Baffling (or a lack thereof) is the main culprit. but even a decent baffle won't keep it all out. The oil vapor will float up past any baffle, so older engines suffer even more.
Give oil a place to build up, and eventually it will.

Paul

 

[DirtDonk]

I should have taken pics of the comparison, but to show how important baffling is, the difference between the PCV baffle on an early 5.0 vs the later-most models, like the Explorer, is huge. I'd say the Explorer baffle grew to about 2.5 times the size of the earlier Mustangs and such.
Must've been a problem for some, for them to bother changing it that much.
There are plans over on the Mustang sites on how to build a larger baffle, and after looking at the underside of an Exploder manifold, I can see where they got the design!

Might be worth noting if you're doing a new conversion, or have your old manifold off for any reason.

Paul

 

[Ned]

I will let you you know how the oil build up gets, I got a crome dome style oil cap / breather for the drivers side. I have to go to Nappa for the PCV. Maybe I will get her up and running this weekend barring any rain.