Vacuum Question

[mopar Joe 65]

On my 65 fury I have an aftermarket air cleaner so I vented my valve cover to the back of manifold I just ran it for awhile to charge up the battery and noticed some oil on the hose if I pinch the hose you can really feel it sucking and the idle drops way down, does this sound normal ? Also would I be better off running the hose to the air cleaner ? Thanks for any help.

 

[rags]

Also would I be better off running the hose to the air cleaner ?

YES!

 

[Big_John]

On my 65 fury I have an aftermarket air cleaner so I vented my valve cover to the back of manifold I just ran it for awhile to charge up the battery and noticed some oil on the hose if I pinch the hose you can really feel it sucking and the idle drops way down, does this sound normal ? Also would I be better off running the hose to the air cleaner ? Thanks for any help.

View attachment 576050

That hose is not supposed to be hooked up to vacuum.

As part of the early emissions packages, it vents into the air cleaner housing. The PCV on the other valve cover IS connected to manifold vacuum and draws (when the engine is running) through the PCV through the valve cover, through the crankcase, drawing air from the breather on the opposite valve cover.

On older cars (before the 60's) there was a road draft tub that stuck down below the engine and air blowing by it helped to pull the bad vapors (by products from combustion) out of the engine. The bad thing was this wasn't exactly clean air to dump into the atmosphere and deposited some oil on the pavement too. Adding a PCV not only cleaned what was dumped into the air, it also keeps the engine oil cleaner. If you've ever changed the oil in an old car, you'd see what I mean. That drained oil even smells bad.

 

[volksworld]

if your other side valve cover is solid (has no provision for pcv grommet or breather) you could just replace your existing push on breather to one that doesnt have the additional hose barb on the side

 

[HWYCRZR]

Yes you are tied into the main engine vacuum port. The purpose of this breather is crank case ventilation. You are creating crank case suction and will be burning oil as it is pulling it directly to your intake manifold. When you put it on the air cleaner where it belongs, you are only putting a slight vacuum to the breather.
Where you have it hooked now is like putting the shop vac hose about a 1/4 inch above the surface of a bucket of water, you will suck up the water. When it is hooked to the air cleaner it is more like the shop vac hose is a couple of inches above the water, it will create a negative pressure, but not enough to lift the water. (there are probably better analogies, but should help give you the idea)

Edit. as said above on the earlier model with no RH breather or PVC. The cap was just vented.

 

[Big_John]

if your other side valve cover is solid (has no provision for pcv grommet or breather) you could just replace your existing push on breather to one that doesnt have the additional hose barb on the side

There's a red hose going from the manifold to the PCV on the right valve cover.

 

[mopar Joe 65]

Thanks for the input guys , that’s right big John the red hose goes to my pvc valve does that part of it look ok ?

 

[Big_John]

Thanks for the input guys , that’s right big John the red hose goes to my pvc valve does that part of it look ok ?

View attachment 576066

Yep, although most don't use a right angle fitting, but that will work just fine.

You can just pull the hose off the breather to run the car without the air cleaner on.

 

[mopar Joe 65]

I think there is a place on my air cleaner I can mount a nipple for a hose. Or can I just run it without the breather hose ?

 

[1970FuryConv]

Thanks for the input guys , that’s right big John the red hose goes to my pvc valve does that part of it look ok ?

View attachment 576066

Normally, with 1969-1973 c-bodies I've worked on, the PCV is on the left (driver) side and there's an opening in the throttle linkage bracket so the hose can run to the fitting at the center rear of the carb.

Then the breather is on the right (passenger) side such that the throttle and kick down linkage don't interfere with the hose to the air cleaner. Note: parts stores sell open breathers that do not have a hose to the air cleaner

 

[mopar Joe 65]

Thanks for the input, I think I will cap off the manifold and get an oil cap without a nipple on it . What do you think ?

 

[Big_John]

Normally, with 1969-1973 c-bodies I've worked on, the PCV is on the left (driver) side and there's an opening in the throttle linkage bracket so the hose can run to the fitting at the center rear of the carb.

Then the breather is on the right (passenger) side such that the throttle and kick down linkage don't interfere with the hose to the air cleaner. Note: parts stores sell open breathers that do not have a hose to the air cleaner

1969 Breather on left side, PCV on right.

Example:

 

[CBODY67]

For B/RB engines, from 1965 until the pcv was moved to the lh side, the pcv was on the rh valve cover. This was the OEM steel pcv valve in the cup which slid over its tube on the rh valve cover. The lh valve cover had the open breather/oil fill breather on it. Hogs hair inside of it. Enough oil would get into it that it would barely drip onto the lh exhaust manifold . . . as happened on our '66 Newport 383 2bbl. The '66 CAP cars might have had the hose from the oil filler/breather to the air cleaner, but the '67 CAP cars had that for sure, but for '68 all engines had that . . . from what I've seen over the years.

When the breather cap moved to the rr of the rh valve cover, it had a right-angle hose which went to the air cleaner. The lh valve cover had the pcv (toward the rr) and oil filler screw-on cap (toward the front end).

LA motors were similar, but a bit different than the above-noted B/RB engines.

Just my observations,
CBODY67

 

[halifaxhops]

Is it me or is that hose to the breather coming off the back manifold vacuum fitting?

 

[krazykuda]

Is it me or is that hose to the breather coming off the back manifold vacuum fitting?

It's you...

 

[rags]

I think I will cap off the manifold and get an oil cap without a nipple on it .

thank you.

What do you think ?

nice engine bay.

 

[Boydsdodge]

I would also change the location of your fuel filter and also replace that glass filter with a Wix metal filter.

 

[70bigblockdodge]

Just disconnect the hose from breather and plug where it went into manifold. It will chug a bit of oil smoke out when under load (no vacuum for PCV to work) all that is normal. With factory air cleaner it is routed into the housing somewhere (varies by years). It will not hurt to leave it vented to open air, but it may introduce smoke vapors to HVAC system or make a oily spot that will need wiped every now and again.

 

[3C's & a D?]

I think there is a place on my air cleaner I can mount a nipple for a hose. Or can I just run it without the breather hose ?

View attachment 576079

Most aftermarket air cleaner bases have a spot to incorporate this. It will be flat, about an inch wide, by two and a half inches long. There may even be a half inch hole, with two smaller screw holes on either side stamped into the metal. Any hot rod shop, and possibly most parts stores will have the plastic nipple you need. That's the way I would go.

 

[3C's & a D?]

I would also change the location of your fuel filter and also replace that glass filter with a Wix metal filter.

Good eye! That particular model of fuel filter is known to restrict flow.