2x4s tunnel wedge and PCV

Michael C Henry · #1 (**permalink**) 08-21-2006, 07:46 PM

I have a Dove tunnel wedge 2x4 intake. Currently their is a 90° PCV valve in each valve cover. They each are vented to a S&H air cleaner base just inside the element. The left valve cover is going to the front carb which is the primary carbruetor. The venting is making the element a mess and coating the carb including the air bleeds. The engine has the breather stack in the center rear and the right front oil filler tube with push on breather in the intake manifold. The left valve covers PCV valve is towards the front and is close to the hood edge not much more room left.
I'm looking for ideas and examlpes on redoing the PCV system . I've thought about running both PCV valves to a Y then a single PCV valve actually controlling the flow into the under side of the intake plenum. Thoughts?

SCOBRAC · #2 (**permalink**) 08-21-2006, 11:27 PM

PCV valves are designed to operate in, well... a vacuum from the intake and not the aircleaner. It would make more sense to simple stick a breather in the valve cover.

Some engines work better (leaner) with a PCV installed. If yours does simply plumb it to the back of the intake.

Loadco · #3 (**permalink**) 08-22-2006, 04:15 AM

I'm just using one PCV valve. It is attached to the forward carb at the vacuum fitting in the base plate of the carb. I have a oil fill/breather cap in the other valve cover. This setup works fine with one exception. The left bank of cylinders run slightly leaner than the other side due to the PCV drawing it's air below the throttle plate. You can see pictures in my gallery.

J Persons · #4 (**permalink**) 08-22-2006, 05:27 AM

You may have excessive blowby. If your engine is healthy, and it's sucking oil, try adding a baffle below the PCV(s). If that fails, you might try an air/oil seperator. It's a container that internally baffled or filled with a media that will trap oil vapors. The lines from the PCV attach near the bottom, and the line to the carb comes out the top. there is a drain petcock on the bottom, and depending on your engine and how much you drive, may require emptying about once a week.

neverwouldof · #5 (**permalink**) 08-22-2006, 06:21 PM

I'm having exact same issue i believe.... 427 SO with tunnel wedge and it continues to leak oil out of the breather filter. Not a huge amount but enough to make a mess on valve covers. ( i love to drive but not much of a mechanic) Is that an issue with the way the engine is setup or just normal? my oil pressure runs 65-70psi and it runs through oil cooler. can someone put a link or names of the fix? thanks for any help....Keith

Michael C Henry · #6 (**permalink**) 08-22-2006, 08:44 PM

I'm also running about the same oil pressure. I have the Precision high volume oil pump with the provided shim installed. I need to remember to let the oil warm up before getting in to the throttle. The engine is realitively fresh. The 400 miles I put on it the week before last is the most it's seen yet. I have the black finned lemans valve covers . The addition of the Mobile 1 full synthetic oil that weekend may be impeding breakin . The oil temps fell. I'm hoping the rings will seat some more. I'd like to keep the two PCV vents running into one line and then through one PCV valve for flow control. I'd think that the flow split over two valve covers would lesson the volume form each so not to draft as much oil into the system. If that can't be done I'm thinking a twist in breather right side and the 90° PCV valve I allready have in the left cover routed to the hose and fitting I have located in the bottom of the Plenum. Does the PCV valves depend on being upright as in the valve cover so gravity is acting on the valve?

speed220mph · #7 (**permalink**) 08-23-2006, 05:23 AM

Mine blew oil out the breathers until I installed a single PCV valve as shown. Heads are tunnel ports with 2X4's up top on tunnel-ram manifold. Used stock oil-filler cap that's well baffled to prevent oil being sucked into intake and an inline PCV valve. Drilled and tapped manifold on opposite side to accept a bushing and AN fitting with 270 degree swivel with pushlock. Setup works well.

Michael C Henry · #8 (**permalink**) 08-23-2006, 08:22 PM

Where would I get a cap like that and what would I call it ? That looks like it would work for me.
Any identification would be a great help. Motorcraft website only shows a drawing and leaves a lot to be desired.
I have identified painted cap is FORD #DOAE-6A66-A says "AUTOLITE"
Chrome version is Ford #C8AZ-6766-B "MOTORCRAFT EC-2 "
There is also ,if height is limited, a Ford D1ZZ-6766-A = Motorcraft EC-508 in chrome, wide and short with bumps for gripping
I've been calling and drivnig to stores and junk yards ,searching the web (mostly E bay). I've collected some information as I went. Mostly burning time and gas. So! to get this project under way I took an afternoon off to get home to the computer for the E-bay aution closing time on a chrome Motorcraft EC-2 cap. I'm imbarassed to say what I paid, but that part is over with .Those oddes and ends are like GOLD . I will be shopping the swap meets.

Michael C Henry · #9 (**permalink**) 09-04-2006, 02:41 PM

speed220mph
The EC-2 breather cap shown appears to have an open elbow not a PCV valve. What does the rest of the engine openings look like? I was just at a nearby shop that had a bunch of 427s. The owner said I need less breathers and one PCV to pull a vacuum on the crankcase.

Cobrabill · #10 (**permalink**) 09-04-2006, 03:19 PM

PCV?We don't need no stinking PCVs!

Oil puke tank on the fire wall and two road draft tubes.

speed220mph · #11 (**permalink**) 09-05-2006, 05:12 AM

Michael: The PCV valve is under the manifold in-line between the cap and pushlok at the manifold. Different size lines ensure the PCV valve is correctly oriented. As for where I got the cap, it was on shelves in my stack of stuff. All I know it is a Ford something, probably off a mid '70s Cleveland or M-series engine.

Cobrabill: I was thinking about using a puke tank, but with a hidden PCV valve in the system. Then I reconsidered: Why put all that excessive junk in the system when a little old PCV valve will pull a vacuum, albeit small, on the crankcase to evacuate corrosive vapors, keep oil mist off the rocker covers at the breathers and reduce overall weight and complexity. That little old "stinking PCV" valve does the job.

Cobrabill · #12 (**permalink**) 09-05-2006, 08:54 AM

Tom-i have the puke tank with no PCV and have no misting problems.

speed220mph · #13 (**permalink**) 09-05-2006, 09:47 AM

Cobrabill: The misting on my car was under the breather caps. The mist from your engine is going out the road-draft tubes. I suspect you're getting some oil under your car if the vent tubes are doing their job, i.e., venting the crankcase and puke tank.

Back to PCV valves, they have no downside, so why not work one into your engine's crankcase-venting system? It ensures moisture and other damaging vapors boiled off oil in the crankshaft is removed, extending the life of your engine. And this is done without any drain on your engine's power. Maybe because it's considered a anti-pollutiong device?

HSSS427 · #14 (**permalink**) 09-05-2006, 12:32 PM

Have an Earl's breather in the rear driver side valve cover and a matching cap with the PCV built in and an AN -6 fitting on the front driver side cover. The rear goose-neck breather is now blocked off as I was getting a lot of mist being thrown out of that breather.

Here's a close up of the breather retainers I installed which seem to seal and hold the breather caps down much better and have baffles built in.

Summit part # CSI-680 $49.95

So far so good

Michael C Henry · #15 (**permalink**) 09-06-2006, 09:09 PM

are all PCV valves pretty much the same? If they are then why so many different applications? A lot of the valves look the same ,if they wern't still in the package you couldn't tell one from another.. Some have addon plumbing. Is there really a difference or just find one that fits?

speed220mph · #16 (**permalink**) 09-07-2006, 10:49 AM

Michael: Positive crankcase valves are calibrated for specific engines. The PCV system on an engine is a controlled vaccum leak as are carburetior or FI throttle plates. The bigger the engine, the more air--crankcase vapor--must be evacuated by the PCV valve. Therefore, PCV valves are calibrated to the requirements of the engine. However, if you choose a valve which was used on a larger engine such as 6--8 liters, one valve will work.

The thing you hear when shaking a PCV assembly back and forth is a spring-loaded shuttle valve. This valve is forced against a spring by manifold vacuum and crankcase pressure. Thus, it maximum flow restriction at idle and wide-open throttle to limit air/fuel mixture leaning. The spring pushes the valve open to provide maximum flow during part-throttle operation. So, if your engine is jetted toward the lean side, the addition of a PCV system will require slightly fatter jets.

Carnut427 · #17 (**permalink**) 09-07-2006, 10:58 PM

Quote:

Originally Posted by Michael C Henry

are all PCV valves pretty much the same? If they are then why so many different applications? A lot of the valves look the same ,if they wern't still in the package you couldn't tell one from another.. Some have addon plumbing. Is there really a difference or just find one that fits?

If you check the application guide for a specific year, you'll usually find that all V8 engines of a certain make used the same PCV valve; 6 cyl engines usually used a different one. This is true for both Ford and Chevies, so the difference is mainly what will fit; I'd personally stay somewhere near the same year as the engine you have in case things such as computers etc. affect them. Don't know that they would, but just to be safe...
JMHO,

Dan

Michael C Henry · #18 (**permalink**) 10-28-2006, 12:09 PM

I have an chrome Motorcraft EC 2 breather cap for the right valve cover ,I have a squaty black Autolite EC 508 cap for the left valvecover. I have all the fittings and so on to create the PCV suction from the intake manifold plenum as speedd220mph did but a short squaty cap for the left fron valvecover opening. I bought a chrome Motorcraft EC 10 cap for the oil filler tube in the right front corner of the intake manifold. It is domed like the EC 2 but has a hose nipple on the side and is a push on. Problem the filler tube is too close to the aluminum valvecover. The filler tube appears to be a little short. That has been a problem in the past as it is only 4 inches tall from the intake manifold and is several inches shorter than the valvecover and a funnel is tipped. Question , Are the all baffeled filler tubes in the intake all soo short? Can a longer baffeled filler tube be bought ? Or do try to remove my tube and have an extension welded on to the bottom with an angle to kick the top of the tube out slightly from the aluminum valvecover th clear the new EC 10 push on cap.
I've ordered a plate to cover the breather opening in the rear of the manifold and I have a PCV plate adapter for that rear opening where I currently have a PSE breather stack. I bought an alluminum 1/2" T to connect two hoses from one valve cover and I had planned on the EC 10 on the filler tube for controlling the fresh air intake to the crankcase. I've been told that I need to limit the fresh air intakes and breathers to form a vacume on the crankcase with one PCV either from one valvecover or the rear intake position wher the breather stack is now. Descusion p[lease.

Carnut427 · #19 (**permalink**) 10-28-2006, 09:03 PM

Mike, my oil filler tube on the front of the intake sticks out 4 1/8", so that's probably the standard length. I don't know of any others available. I have chrome pentroof valve covers, and my breather just touches it, so I can see where you'd have a problem with the thicker aluminum covers. I believe the breather on my front tube is larger in diameter than the originals, so I'm going to guess that's the direction you need to go...a smaller OD breather. Sorry, don't ask me where. With so many people running the aluminum covers, there's got to be one available.
I suggest you run the PCV out of a valve cover and block off the rear breather hole in the intake. As you've been told, all you need is one fresh air intake (breather) and one PCV. You can run the PCV to the large tube on the base of the carb. It should be the same size as the tube coming out of the PCV valve (3/8").

Dan

Michael C Henry · #20 (**permalink**) 10-29-2006, 08:33 PM

The decsions on the final PCV set up are yet to be made. But if carbs are jetted bigger for a PCV system Then maybe I should wait to see when I actually have a PCV system to see if the #66 jets I'm running now work out,I've checked the manifold vacume paths to the power valves and they were open. I changed powervalves going bach up from the 3.5 to 6.5 which I was told my carbs would handle.
The exhaust pipe idea sounds like a likely avenue. What I emagined was a slightly taller pipe with a cut and weld near what would be above the base located in the intake manifold forming a slight bend ,installed so the top was a little farther from the right valvecover.