Technical PVC Breather system

Plan on upgrading with intake and carburetor, and ready to run distributor on 327. I have the old intake with the breather/filler tube I'm going to eliminate. What the best way to proceed, breather/pvc in the valve cover or pvc and tube running to carburetor base, or what?

 

PCV valve in one cover, breather in the other one. Yes, PCV hose goes to manifold vacuum at carb base or intake. Make sure there is a baffle inside the valve cover under the PCV valve to keep it from ****ing oil.

 

You should have a vent port at the back of the block to deal with.
I might suggest you also dump that plastic fuel filter next to the exhaust manifold.

 

Thanks, So I can run either from PVC in valve cover to vacuum inlet at back bottom of carb or the vacuum port on intake behind the carb?

 

What vent port are you referring too? The plastic filter I had planned on relocating with different one , it's not quite as close as picture shows.

 

PVC is a type of plastic pipe.
PCV is Positive Crankcase Ventilation.

just wanted to get that straightened out.

There might be a road draft tube at the back of the block, behind the intake manifold. That's what he's talking about. The early engines, up through the late 60s, had two holes for breathing--one is the filler tube in the intake manifold, the other was a road draft tube, then later a hose fitting for a PCV valve, at the back of the block. Starting in the late 60s, they quit making the hole in the back of the block, and in the intake, and started using valve covers with holes in them, one side connected to a PCV valve, the other to a breather tube that went into the air cleaner.

Normal procedure when getting rid of the early intake, is to use later style valve covers with holes in them, and plug the hole in the back of the block.

 

OK Thanks ,yep had my V&C backwards, This is a 1968 327, no tube underneath, can't see any breather hole in back of block under side . Valve covers already have breather in one and pugged hole in other, so should just be able to add PCV to it.

 

The PCV valve on my 57 T-Bird is plumbed into the hole where the old road draft tube was. It has worked well for the last 25 years.

 

The intake manifold in your picture shows the oil fill tube/breather at the front. The heads have no accessory holes in them. These point to an early engine (55 - 67). In 68 the block design changed, gone was the road draft hole in the back behind the intake manifold, and the oil fill tube at the front. Can't tell from your picture what you really have, it's entirely possible somebody put earlier heads and intake on an later block. The bottom line is, on an early block you can adapt a PCV to the road draft hole, there are kits available to do this. Or you can plug it and place the PCV in one of the valve covers. On the later block just put the PCV in a valve cover and breather in the opposite valve cover. You could leave the fill tube breather alone and the PCV will draw through both (or which ever one offers least restriction).

ETA: according to this article, the double hump cylinder heads (with no accessory holes) were used through 1968.

 

The block code shows its a 1968 . Not sure where draft hole is suppose to be but can see any plugged holes ,

 

Just checked back of engine manifold, no draft tube holes

 

OK, so PCV in one valve cover, breather in the other. Plumb the PCV to manifold vacuum. You already have a breather in the driver's side valve cover, you can probably adapt a PCV into the p***enger side valve cover into the oil fill cap with something like this. You'll have to do some shopping to find one, or maybe one of the guys here has a link:

 

Thanks, the p***enger side has the rubber plug so easy fix. Can I go off the vacuum port on the back bottom side of carb, or in top of manifold vacuum port

 

are you going to use a different carb, too?

The PCV valve is usually connected to a large port on the base of the carb, but it can connect to a fitting in the manifold instead. The early carbs don't have the built in 3/8" hose fitting that the later ones usually have for this. It might have a threaded hole in back that might be big enough.

 

Plug a PCV valve into the p***enger side valve cover, and into a port behind/in the carburetor with a length of hose. And why change anything out on that engine? I'd leave it the way it is; looks like a good, traditional setup to me. JMO.
I am Butch/56sedandelivery.

 

Plan on this setup for carb/manifold, carb's a 650, should have all the ports.. That's where I had it on my 50 chevy, carb port . I have brake booster vacuum and will be connecting line for new 350th I installed, could tee that to the manifold port. Planning on ready to run distributor , not enough room for HEI. any distributor setup you recommend without breaking the bank.

 

Not traditional but the H.E.I. should still work on your new set up
Not having a oil fill tube and holes in valve covers date the engine also.

 

The picture that oilguy posted shows where the road draft tube/ early pcv valve on the back of the block next to the distributor is mounted, black thing with the hose on it next to the oil pressure sending unit.
Later blocks have a flat area with no hole there

 

I have the front motor mounts. Everything I've read said not enough room for regular HEI. Not much room to firewall now with stock distributor

 

Yes checked it out nothing there, or ever has been

 

While the inlet end of a PVC system comes from the air filter housing in many OEM systems, the source is outside of the actual air filter, it has instead a small filter dedicated for the PVC only. inside the housing .When drawing air from the common aftermarket breather its worth mentioning that most of those breathers are simply to stop oil from blowing out with excess vapor , AFA filtering , they may keep out large bugs & small birds , not much for dust . The pleated cloth breathers or an equivalent are better suited to actually filter dust out of incoming air .

 

Okay, I have to ask, what is the advantage of a pcv instead of the oil cap type breather?

 

Pcv is constant air movement , constantly remove oil vapor & combustion , gases from the crankcase ,improves ring seal , keeps the oil from becoming acidic , & burns the by products therefore its good for the environment ! A breather simply can't do all that. !

 

....and I just put a hole in a Performer RPM manifold for a fill tube so it would look traditional.

Gary

 

I drilled and epoxied a oil fill tube in a Vortec intake manifold for the stock 1964 look.
That was a while ago, I still don't think any one makes a vortec intake with a oil fill tube hole.

 

Pertronix...

 

Unless there a certain one, everything I see says there a standard size cap. If there bigger then the stock points one, like all I've seen, not enough room.

 

I used to date an engine, I was young and didn't know any better

 

And Dad was wondering why his engine oil was contaminated
Did she have valve cover breathers or oil fill tube

 

try summit/jegs for under carb spacer with a 3/8 hose vent .itl work