on my 57ranchero i drilled a capscrew and welded a fiting to adapt a hose then a pcv valve from a 351,capscrew went into the ds head axcessing the push rod hole, then to the bace of the holley 4v. i left the original .road draft(left front of the block) iget some air frome the filler cap,balance from original rd tube. no leakes ,did this as got the od whif of blow by after a long run.my project started as i wanted pcv valve ,but did not want to remove the  int and mod the valley cover. will eventialey redo with the proper ,or mod the existing one.Iwas concerned i would pickup oil as get lots to the rockers and pluged the bleed tubes.litle or no oil gets by pcv,and no negitive vacume in crankcace.
never smell blow by ,does not use any oil.the engine has aprox 70000 miles with rebuilt heads andholley 4v aswell dura spark ign runs like a charm

I don't want to start a new issue with the road draft tube.  Mine would push out a quart of oil in 20 miles oiling the whole under side of truck. 272 bored to 292 and fresh.  Put on a evac system thru valve covers and hosed to the collectors on headers.  I have oil pushing out fuel pump and leaking out pvc valves on headers.  So I still have an issue.

That style of evacuation system is only effective on racecars that see high rpm.  It won't solve your problem and will probably cause more.

A quart in 20 miles seems like a bad valve cover gasket, oil filter gasket, oil pump gasket, something like that.  You sure it's coming out of the road draft tube?
If the road draft setup was clogged, then your crankcase will pressurize, which can force oil out of many places and the evacuation system you have installed will not help that when used in a street vehicle.





Lawrenceville, GA

I installed a lot of PVC "smog " devices in So Cal in 62-65 when I worked fo Sears. We ruined countless rocker covers and put plugs in road draft tubes. My 56 is starting to show "breathing" from the road draft tube but it is dry with no drips at all or smell I can detect. I am assuming every open engine would show something unless you've installed Total-Seal piston rings. (Ted is this a good idea for street engines?)

I have the rear breathing valley cover ready to go which I would refit with a PVC. Personally a PVC is not a bad idea both for the environment and to keep your engine clean since you are running under a slight vacuum. The test at Sears was a device we set on the filler cap that showed a vacuum by a ball moving. I would slide a piece of paper over the tube and if it stayed they even under reving the engine it was good. A poor condition engine under reving would not hold the paper because of too much blowby. If I ever need to remove my intake I'll probably do it.

56 Vic, B'Ville 200 MPH Club Member, So Cal.

As Charlie brings up, header evacuation systems are specifically for race cars running open headers.  On the race cars, these systems by design remove air from the crankcase which reduces the drag on the crankshaft and other moving parts.  These system still incorporate a check valve at the header collertors to eliminate any possibility of any backpressure making its way back into the crankcase.
 
Vacuum systems that use the exhaust flow as the flow driver are typically non-effective in daily driver situations when hooked up to an exhaust system that has mufflers or long small diameter pipes.  This is simply due to any back pressure present reducing the negative air pressure flow across the installed nozzle and subsequently prevents a vacuum or negative pressure from being generated.  These types of vacuum evacuation systems are ideally suited on open headers that have no mufflers and as a result, these systems do work well on the racing applications.  Here’s a picture of the evacuation system on my roadster.
 

Lorena, Texas (South of Waco)

I typically only use gapless rings on those applications where I’m minimizing the contaminants getting into the oil.  Supercharged with injected alcohol is one of these applications.  On a street car, I typically don’t recommend gapless rings simply due to the lack of oil that can get past them thus increasing the wear factor.  I did run a Ford 427 High Riser on the same set of gapless rings in excess of twelve years and to their credit, those rings were still sealing good at the end of their reign.  The heads were thoroughly worn out at that point though but simply due to lots of running and nothing to do with the gapless rings.  The cylinder walls were also heavily scalloped but that had more to do with the thin wall casting design of the 427 side oiler block and the 0.009” piston wall clearance and not the gapless rings.

Lorena, Texas (South of Waco)

Been following this thread with interest trying to sort out a pcv plan. Check out this pic of what I have here:

I think the fitting I have on the aft end of the valley cover came with the Mummert intake. If I want a closed pcv system should I stick the appropriate size pcv valve inline between this fitting on the valley cover and the hose barb coming of the back of my carb? Or the threaded hole in the boss on back side of the intake? I'm thinking carb.
Also, then I get an oil fill cap that has a tube for a hose and run that into my air filter? Am I close with any of this? Thanks

Bill C

Drag it home, figure it out.

Short answer, yes. I'm using a PCV valve very much like your fitting in the valley pan. Goes into a grommet, and a hose to the carb fitting. I've used the manifold fitting like you show, also.

One of my cars has the closed cap, running to the a/c. The bird has a finned valley cover and I used the fill tube off a 69 Camaro. Sealed cap (looks like a radiator cap) with a bung for a fitting to the a/c. The OEM application was a PVC that screwed in there, I used a barb.

One caveat. The original valley pan didn't have a baffle, and I used a Moroso grommet with a "duck bill" design, to limit oil flow. When I built the new motor with the high volume/pressure oil pump, it didn't control the spray coming off the dizzy drive. That was a blower motor. Blew the head gasket on #7 twice before we realized the oil contamination was the likely cause. Welded a proper baffle under the valley cover, no more problems.

miker
55 bird, 32 cabrio F code
Kent, WA
Tucson, AZ

Bill C that's correct. Most forget that the PVC valve is a flow device so the vapor it is sucking out of the engine is actually thru the engine and it should be filtered air. If you remember many GM cars had that filter inside the air cleaner but outside of the carb air filter and is an easy one to add. Many of the early PVC valves were threaded and I have one of those 69 camaro fill tubes withe sealed cap where you would place the valve. If that style is used however there should be a breather cap on one of the valve covers with a hose up to a filter also that's how they (GM) did it. Good luck and I like what you've done so far..

56 Vic, B'Ville 200 MPH Club Member, So Cal.

I'm using the same set up as yours. I have the PCV valve inline between the valley cover and the carb. To use the manifold fitting would have required a large loop of hose to avoid sharp bends and kinks, going to the carb allowed a shorter hose with a smaller loop. I also use a filler cap with a hose going to the air cleaner.