crank case evacuation idea's with baldy valve covers

[e philpott]

anybody ever run there crankcase evacuation set up through the intake fill tube to header collector ??..... thoughts ?? ... Jay ??


installing baldy's valve covers , had cobra valve cover and a crank case breather in each of the valve covers , now need to move my breather somewhere else ...... was thinking of running one breather from my fill tube and then Y connect to each header collector , it would be one breather instead of two like the cobra valve covers but was worried about sucking oil .......

 last resort would be install the breathers into the Baldy valve covers but would rather not do/modify the valve covers , but also don't want to blow oil into my exhaust system

thanks , eric

[blykins]

Are you running a mechanical fuel pump?  If not, you can scavenge off the block off plate.  You can also pull from the oil pan itself.

[Joe-JDC]

You don't want to scavenge from any place that get oil from slinging/rotating assemblies.  You will smoke and use up the oil very quickly.  It would be better from the road draft tube mount if you have it, than the oil fill tube.  Look much more professional, also.  Joe-JDC

[blykins]

You can scavenge from either place on the bottom end that I mentioned, run through an oil separator, and then through a check valve to the header.   We have to do it this way when we restrict the way the crankcase vents to the upper end, like in an application with standpipes in the valley, or an enclosed cam tunnel.  It really makes sense too, because you're wanting to directly pull vacuum on the bottom end of the motor....doesn't really matter what the valve covers are seeing.

[e philpott]

I do have a electric pump , but would rather keep the breather up top

is the rear a better place for the breather than the oil fill ??..... was thinking the oil is draining back at the rear might be worse than up front , but I like the road draft tube idea , I would need to get one though but no problem or fab something up .... does the road draft tube have mesh on the inside to keep oil out or just open ??


I'm still surprised my old F O R D valve cover clear the Dove end stands without modification

[jayb]

Factory road draft tubes had a mesh basket under the tube, and I think that would probably work pretty well in a pan evac setup.  Make sure the tube coming off the back of the manifold has the half moon baffles in it, and that and the mesh basket ought to do a pretty good job of keeping the oil out of the exhaust.  When you get it fabbed up, Eric, let's see a picture!

[Heo]

On My 64 PI engine with baldy covers the PCV valve is at the rear of
The intake probably where the roaddraft tube is and the air enters
Through the Oilfilltube
I dont remember whats under the PCV valve and om not at home
Right now.

[XR7]

I put a set of pentroof valve covers without holes on my 428 not that many years ago. Looked great! I tried to use the manifolds rear breather hole with the steel wool insert inside etc, and hooked a hose up to one header collector evac valve, and it sucked oil like no tomorrow. It looked like I blew it up the first pass going down the track. Everyone ran up to me.. what happened...? I said nothing... ran like it always does. They said no way man you were smoking like crazy! Well I even tried placing a disc in the bottom of the breather basket with just a few 1/8" holes in it, still sucked oil. OK... next went to a oil separator tank and plumbed that in line. Well, it worked for 2 passes then it was full of oil, had to drain it every other pass or it was a mosquito killer. I gave up and put my old valve covers on. 

Now I did have roller lifters and no valley tray, so maybe that had something to do with it, but in no way did it work for me trying to use the rear breather. I never have had any issues with oil getting sucked into the headers when using the baffled valve covers, ever.

[e philpott]

my Cobra VC's are too tall , I can't run the wiper motor and it makes spark plug access terrible , can't take VC's off unless I remove the tower brace , ec t , ect ..... I'll have the baldy's modified before the Cobras back on , they just open up the engine compartment so much..... this engine has never had any blow-bye and I do run the tray ..... maybe I'll try the front oil fill tube first before I modify the Baldys ...... I'm doing a cylinder head freshen up (new valve springs) and finally getting around to installing my Med 2x4 too

[Joe-JDC]

If you look at the oil fill tube, it has a slot/disc in the bottom to keep splatter out of the fill neck, yet allow the oil to empty into the valley quite rapidly.  If you put a simple extension on top of the road draft basket, that would eliminate sucking oil droplets into the scavenge lines.  It would look much nicer at the rear of the engine than up front at the fill tube, and be less complicated, or in the way of everything else like spark plug wires, or fuel line, etc.  Not that hard to do.  Joe-JDC

[chris401]

If you look at the oil fill tube, it has a slot/disc in the bottom to keep splatter out of the fill neck, yet allow the oil to empty into the valley quite rapidly.  If you put a simple extension on top of the road draft basket, that would eliminate sucking oil droplets into the scavenge lines.  It would look much nicer at the rear of the engine than up front at the fill tube, and be less complicated, or in the way of everything else like spark plug wires, or fuel line, etc.  Not that hard to do.  Joe-JDC

Would that work close to now PCV does with a street engine?

[Joe-JDC]

Yes, but you get more vacuum if connected to the headers for scavenge, which is what is desired for reducing the crankcase pressure enough to increase horsepower for drag racing purpose.  Joe-JDC

[e philpott]

my heads and intake will be gone for a week , so I'll have to see how it pans out when I get my parts back ..... I'm still going to have a bunch of little problems like throttle linkage from 1x4 to now 2x4 , I lived with the intake side of the valve cover rail .080 higher than the heads so I'm not going to have that this time either

[chris401]

Yes, but you get more vacuum if connected to the headers for scavenge, which is what is desired for reducing the crankcase pressure enough to increase horsepower for drag racing purpose.  Joe-JDC

I have seen them run on street, just wondering how well it worked idle to 3500. The two old gas GMs were constantly oily around the oil fill/vent. The 08 Cummins was clean. It was a bolt on deal and I really didn't want to hear any more than necessary from its owner.

[gdaddy01]

I am running a breather on the back side of eld. two four intake and I plumbed the pcv valve into the fuel pump block off plate , used a oil pump pickup tube , bolt pattern almost the same as block off plate , used a short piece of hose and a 90 degree pcv , with hose clamp . use that for oil fill also , small funnel , almost can't see it , works very well . I also put some filter foam in the intake stand pipe on the back of the intake to make sure no dirt gets sucked into the engine , no oil leaks at all , have put about 3000 miles on ranchero , 390 , two fours and a four speed .