Crank case ventilation

[Cannuck]

Hi i have been searching for the proper way for the vent cap to be sitting on the tube . I have seen pics with the cap mesh to the front and pic with the mesh to the firewall . I searched my manuals and could't find it. My mesh  is towards the firewall .  Maybe it doesn't matter don't know .

[OUTFXD]

Top of the oil fill tube will have a sizable dimple.  Look on the underside of your vent cap and there should be a corasponding lump  to fit into the dimple. the fill tube it self has no proper orientation so as long as the cap is ON the tube, I dont think it matters which way it faces.

[D35 Torpedo]

The top of my tube is all kinds of wrecked. Looks like it was crushed a few time. So the cap fits on several ways. I was pondering the same question. Right now i faced it forward so the fan can force air in, to help the road draft tube scavenge the crank case. Makes sense to me. I guess i could google images to see what way the sticker orients.

Edited March 21, 2023 by D35 Torpedo

[Cannuck]

Yes i know about the dimple I was just wondering about the proper orientation of the screen .Someone in its history may have removed the tube and rotated it 180. I thought the same as you D35 that facing forward would be correct 

 

 

thanks 

[JBNeal]

Cap filtered opening faces the firewall...air is not forced into the filler cap, but drawn through it by the downward vent tube.  I read somewhere that once ya get over a certain road speed, that vent tube starts to draw a vacuum on the crankcase as air passes around the tube tip.  The firewall facing cap vent has a lower pressure at the cap opening than if facing forward, this allows air to flow into the crankcase and fumes to draw out though the vent tube.  Compared to a full PCV system, that road draft tube seems kinda hokie 

[D35 Torpedo]

Interesting, I thought if it faced the firewall, it would draw a vacuum as air passes it. Which would combat the vacuum at the road draft. Face it forward and there is a slight "ram air" effect, adding to the vacuum made by the road draft. Anyways, it's a product of its time and it did work. You really don't need to be moving that fast to pull a vacuum. Pcv's came in for emissions, not because the road draft was not effective. If my engine was old, I'd probably fit a pcv just to manage the blow by and eliminate the stink when stationary. 

[OldPly]

2 hours ago, JBNeal said:

Cap filtered opening faces the firewall...air is not forced into the filler cap, but drawn through it by the downward vent tube.  I read somewhere that once ya get over a certain road speed, that vent tube starts to draw a vacuum on the crankcase as air passes around the tube tip.  The firewall facing cap vent has a lower pressure at the cap opening than if facing forward, this allows air to flow into the crankcase and fumes to draw out though the vent tube.  Compared to a full PCV system, that road draft tube seems kinda hokie 

It should face the firewall , yes if it faces forward it will FORCE air into crankcase and all the road dust from the car in front of you . Mother mopar put a lot or thought into little things like this .(some of us don't understand way but she did)

My house is across the street from a school , you would be surprised how dirty a car can get from road dust.school buses people picking the kids etc not driving fast.  if car does not move for a few days i have to clean windshield 

 

Edited March 22, 2023 by Karey
More though

[Cannuck]

Ok thanks to everyone I will leave it facing firewall