Putting a Stop to Oil Consumption through the PCV Valve

Discussion in 'Fox 5.0 Mustang Tech' started by vristang, May 20, 2006.


  1. CRASH7772

    CRASH7772 New Member

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    That's what I was wondering......if that line is supposed to flow into the VC then how does oil flow out to the TB? I'll see what I can do about the baffle in the VC but I think I will try the check valve in the TB/VC line for a bit anyways.
    #21
  2. vristang

    vristang Advanced Member

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    Let us know how it works

    :nice:
    #22
  3. TheRedBlur

    TheRedBlur Active Member

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    I'm guessing if you have the valvecover baffle removed, then the rocker arms can splash oil up to the hose, and the vacuum just sucks that **** in. right?
    #23
  4. CRASH7772

    CRASH7772 New Member

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    That's what it seems but it also seems that this is the fresh air charge line that feeds clean air into the engine which allows/pushes the dirty air into the PCV system to be reburned. But vristang mentions that this line might need to flow both ways......if that is the case then where does the clean air draw from (I'm not saying your wrong on the bi-direction as I don't know for sure).
    #24
  5. vristang

    vristang Advanced Member

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    This seems to be exactly what is happening, as most often the addition of a valve cover baffle (and no other changes) will completely eliminate oil control issues in this line.

    All the baffle needs to do is block the splashing oil from getting up the filler neck.

    EDIT: Don't think of it as oily air being pulled through the TB/VC line. Instead think of it as oil being flung into the TB/VC line by the rockers.
    If you have ever adjusted valves with the valve covers off you know how messy this can be.

    jason
    #25
  6. vristang

    vristang Advanced Member

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    SOME situations could force flow through the TB/VC line. In my mind these are mostly transient or short term phases. For example, WOT will create a fair amount of pressure in the crankcase, but there will be relatively low levels of vac in the intake. Since there is little intake vac to pull the gasses from the crankcase, the crankcase will be free to vent anywhere. Coincidentally, at WOT there is somewhat of a venturi affect where the TB/VC hose enters the TB. (this is similar to how air rushing through a carb will pull fuel into the intake stream)
    This is the only situation I can think of at the moment. Again, this is just a theory I have heard. However, if Ford didn't think there needed to be a directional valve on the TB/VC line, I am inclined to agree with this theory.
    I am still undecided, so maybe someone else can offer some input?

    jason
    #26
  7. TheRedBlur

    TheRedBlur Active Member

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    I'm thinking that in a stock engine setup where the pcv system is optimum, at idle, the pvc generates enough vacuum to allow air from teh intake tract to enter the crankcase, since the throttle body is near closed.
    #27
  8. arbailey

    arbailey Founding Member

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    Would it be possible to drill a hole near the front of a stock 5.0L EFI valve cover (driver's side) and install a grommet with a stock pcv valve, and run a hose from it to the upper intake manifold (along with the one that is already in the lower intake manifold)? Would this grommet/pcv valve clear roller rockers, and would it work with a Cobra intake?
    #28
  9. arbailey

    arbailey Founding Member

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    Damn double post!
    #29
  10. arbailey

    arbailey Founding Member

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    Damn triple post!!
    #30
  11. vristang

    vristang Advanced Member

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    It is possible and I was very close to doing that very same thing. If you take the time to lay out the position of the pcv in the valve cover you may not even need a baffle. For example, if the pcv is next to the rockers (instead of above them) then the rocker shouldn't be able to splash much oil up the pcv valve.
    This is just my idea though, I have never tried it.

    Be careful to get the hole and grommet sizes right, as the fit needs to be tight.

    If you make it happen, please come back to this thread with results.
    I would be interested to know how it works.

    jason
    #31
  12. TheRedBlur

    TheRedBlur Active Member

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    if this helps you guys visualize. Here's my valvecover, I had to remove the baffle and grind the ****er out to clear my rockers. You can see how the original baffle kept the oil from being slung up by the rockers. I personally don't have the oil problem from my VC->TB. If it does develop, I don't see how it should be too hard to rig another baffle, inside the filler neck.
    [​IMG]
    #32
  13. tmoss

    tmoss Gettin Wired Founding Member

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    Stuff coarse steel wool in the filler neck and use some perforated sheet metal tacked to the bottom of the steel fuller tube crimp to hold it in there.
    #33
  14. $uperstang

    $uperstang New Member

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    Well, the idea of two PCV valves is interesting. I used the seperator in my cobra intake and it fills up to the top in 10 miles! Now I was going to try plugging the stock location PCV and moving it to the valve cover on the driver side. I have the tall Ford Racing valve covers with the baffle in place on both. But I never thought about running two PCV's? Should I try two instead of capping one off first? I figure I would cap off the problem area first and try that.
    #34
  15. arbailey

    arbailey Founding Member

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    A PCV revelation.....LONG

    I just had a revelation. When we installed my FMS roller rockers underneath my stock 5.0 EFI valve covers we needed to raise the baffle so it wouldn't hit. We did this by grinding some of the material from the baffle's mounting point, and then re-installed the baffle. It worked, and the rockers did not hit it. Now when I do an oil change and I pour oil into the filler tube, I have to pour it VERY SLOWLY or it will "burp" and overflow. Which I thought, no big deal, I just pour it VERY SLOWLY. HOWEVER, since I've been following this thread I started thinking that if the hose from the filler tube to the TB may also relieve crankcase pressure and it is partially blocked by my now raised baffle, could that also cause excessive crankcase pressure/vapor/oil to be pushed through the pcv and into the intake? Next, does anyone know what aftermarket or Ford Motorsport valve covers will work with #1) stock E7 heads, #2) 1.6 ratio Ford Motorsport Roller Rockers, #3) provide a spot to mount a second pcv valve on the driver's side? #4) will work with the stock 5.0 mustang intake (I have a 3/8" spacer I can use if necessary but not sure if the stock hood will close) For those of you who run the valve covers with the pcv grommet on each side, what do you use for an oil cap, and are the pcv grommets baffled underneath?
    #35
  16. vristang

    vristang Advanced Member

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    That is an interesting idea. :hail2:
    It would help us to understand if the problem has to do with the PCV being mounted in the lifter valley.

    If you try this out, please post the results here.
    I would love to hear how it goes.

    jason
    #36
  17. vristang

    vristang Advanced Member

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    I don't think that the raised baffle would really restrict airflow, even if it does restrict oil flow. The difference in viscosity between oil and air is rather large.
    Then again I am not a physicist (I'm not even sure I spelled that right:shrug: ), so maybe others will have an opinion.

    I am using Crane 1.6 rockers on the stock valve cover on the passenger side. On the driver side I used a "Powered by Mustang" (or something to that effect) valve cover. I did have to grind a little on the driver side cover too. The baffle I am using on this valve cover is integrated into the pcv breather cap.

    jason
    #37
  18. arbailey

    arbailey Founding Member

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    Do you know if those valve covers would work on a stock intake with a 3/8" spacer? What about this - run valve covers that have grommets in both, install pcv valves in both, T them together, then run a line from the T, to the upper intake manifold on the opposite side of where the factory pcv goes, plus leave the factory pcv setup in place? Could anythind bad happen?
    #38
  19. tmoss

    tmoss Gettin Wired Founding Member

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    I seriously doubt anything bad will happen........
    #39
  20. vristang

    vristang Advanced Member

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    My only concern with putting a breather/pcv on the same valve cover as the inlet for the fresh air (TB/VC line) is that fresh air will not be pulled through the crankcase. The path of least resistance for the fresh air in this setup would be to simply flow out the other end of the same valve cover.
    Whether this is an issue or not, I don't know. I can't even think of a good way to prove it either.

    jason
    #40

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