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Technical The PCV dead horse rides again!!

Discussion in 'The Hokey Ass Message Board' started by DaytonRon, Sep 7, 2017.

  1. DaytonRon
    Joined: Aug 31, 2017
    Posts: 9

    DaytonRon

    Hi all, YES this is a question about SBC PCV systems with older (no-hole) valve covers. YES I have read all the old threads and thanks to all for their valuable knowledge! BUT, my situation was not covered exactly so I'd like to describe what I intend to do and get some feedback from the experts:

    The Block is a 1968 truck 327 factory crate engine (warranty replacement) - 2 bolt mains WITH the road draft tube hole next to the dist. WITHOUT the cast-in oil-fill tube provision at the front!

    The intake is a Weiand 8004 dual plane, filled and painted to look factory but also WITHOUT an oil fill tube hole or boss (there is a flat spot however - NOT big enough to mill for an oil tube but big enough for a threaded PCV valve.)

    What I intend to do: In the spirit of back-asswardness:

    1. I intend to drill and tap the front of the intake manifold pad (where an orig oil tube might go)for a threaded PCV valve and plumb it to the back of the Q-jet for vacuum.
    2. Utilizing 1.25 inch O.D. brass or copper plumbing fittings, place a 45 degree elbow in the factory road draft tube hole (1.25in) and then about a 6 inch long piece of the same plumbing tubing running up and away from the distributor to a spot just over the firewall corner of the driver side valve cover. I will cap this tube with a small universal valve-cover breather and this is where I will fill oil from the top and where the engine crank case will breathe from.

    So . . . will I need an original chevy oil vapor separator under the intake to keep the new fill tube from blowing oil on my windshield or will the vented breather cap be enough? Will this system work? Has anybody done this nonsense before?

    Apologies for the length of this but . . . meh . . you know!
     
    chryslerfan55 likes this.
  2. Sounds like it will work well enough, it is certainly thinking outside of the box. You should be high enough to not get oiled without a baffle and a baffle would make it a slow filler anyway. I would try it, the hard part is making it look not too steam punkish. :)
     
  3. DaytonRon
    Joined: Aug 31, 2017
    Posts: 9

    DaytonRon

    Ha! you are so right! I'm going to paint the tube the same chevy red-orange as the rest of the motor so it shouldn't look too "road warrior" (a little is OK w/me tho!) thanks for the input!
     
  4. the PCV valve you stick through the front of the intake will need a baffle
     
    wraymen likes this.
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  5. Why not use this GM factory part?
    Dixie Cup vent adaptor.jpg
     
  6. ^ This or simply put a grommet in there and use pcv rated for your motor. Then put a breather in your valve cover. You will still need some sort of baffle.
     
    lothianwilly71 and Fordor Ron like this.
  7. DaytonRon
    Joined: Aug 31, 2017
    Posts: 9

    DaytonRon

    That's a good point. Maybe I should just plumb a brass fitting in the intake and run an inline, molar style pcv valve? Will 6 extra inches of hose between the valley and the valve be enough to keep oil out the valve? Not sure I have room for a baffle under the intake. Have to think on that one.
     
  8. DaytonRon
    Joined: Aug 31, 2017
    Posts: 9

    DaytonRon

    Need to put oil in somewhere. (read OP)
     
  9. DaytonRon
    Joined: Aug 31, 2017
    Posts: 9

    DaytonRon

    No hole covers, man. To cool to cut up.
     
  10. BigDogSS
    Joined: Jan 8, 2009
    Posts: 815

    BigDogSS
    Member
    from SoCal

    Pitch the Weiand manifold and get an Edelbrock with provisions for a regular oil fill tube. Then just run a stock Chevrolet open-PCV system. It will look way cleaner.
     
    Automotive Stud likes this.
  11. I completely understand. How about a slightly smaller oil fill tube up front. Tubing as big as you can fit and make your own push in breather cap. You can always put your oil fill tube in the back but not real sure what it will look like. Conversation piece at the shows for sure.;)
    Edit: sorry I missed the part in your post about the rear breather tube. I looked in my stash but did not have any intakes with the fill tube boss or I would send you one.
     
    Last edited: Sep 7, 2017
    lothianwilly71 likes this.
  12. Re invent the wheel
     
    LOST ANGEL and X38 like this.
  13. IMG_0810.JPG
    This is what I did on my old 283. Worked perfect. I used this intake manifold with no problems.

    http://www.speedwaymotors.com/Edelb...hevy-Intake-Manifold-with-Oil-Fill,51954.html

    I ran a hard line from the PCV valve on the back of the engine to the front of the carb so it would suck from the rear and pull in fresh air from the front breather. Worked perfectly. No valve cover breathers needed.
     
    Last edited: Sep 7, 2017
    Dave Downs and wraymen like this.
  14. DaytonRon
    Joined: Aug 31, 2017
    Posts: 9

    DaytonRon

    no can do - that Weiand 8004 is the manifold I wanted in high school and this is "that" build (the "I'm young, dumb and full of . . well you know" build.) So, I'm going to have to re-invent the wheel as another poster put it - not the first time and like he said - be a great conversation starter with the weird tube emerging from the back of the motor with some funky breather on it! - pics of this to follow.
     
    Clay Belt likes this.
  15. DaytonRon
    Joined: Aug 31, 2017
    Posts: 9

    DaytonRon

    I dig it. That's what I want mine to look like - only reversed!
     
  16. Blues4U
    Joined: Oct 1, 2015
    Posts: 4,327

    Blues4U
    Member
    from So Cal

    You don't want to cut up the valve covers, but you want to run the manifold because that's what you've wanted for a long time. Then pull the valve coves off and stick them aside for a future project and get some other valve covers with the holes for PCV/breather for this one.
     
  17. DDDenny
    Joined: Feb 6, 2015
    Posts: 13,076

    DDDenny
    Member
    from oregon

    Positive crankcase ventilation, no valve.

    20160118_092513.jpg
     
  18. Here is where I put the PCV valve on my Mysterion clone. Drilled and tapped 1/4" NPT in intake runner on underside of manifold. The draft tube hole is plugged per the original car, no place else to let the motor breathe. Stock 390 comes with a big windage/oil baffle tray under the intake manifold, this valve should not get oil choked.

    P1010407.JPG
     
  19. el Scotto
    Joined: Mar 3, 2004
    Posts: 4,205

    el Scotto
    Member
    from Tracy, CA

    Your plan is fundamentally sound but sounds like it will look goofy as fuck. Please post a picture when you're done.


    Sent from my iPhone using H.A.M.B.
     
    X38 and 31Vicky with a hemi like this.
  20. jimmy six
    Joined: Mar 21, 2006
    Posts: 5,368

    jimmy six
    Member

    PCV= Positively Crap-up the Valves. The system is a good idea but having ur engine rum on unburned gasoline, oil vapors, and condensation is not a very thing for it. Since we must have them on newer cars it best to add a "catch can" or separator and removing it every time you get a smog check as they are illegal and for off road use only. But for us 1973 and older engines that have PCV systems you can put one on and just reap its benefits and your engine can run on air instead of junk.
     
  21. Put your engine together like this -
    image.jpg

    Does that look familiar?
     
    olscrounger and X38 like this.
  22. Chevy Gasser
    Joined: Jan 23, 2007
    Posts: 692

    Chevy Gasser
    Member

    The best way to utilize pcv is to completely ALL oil fumes from engine. The best way is fresh air in one valve cover smoke contaminents out the other. If you dont want to modify your vslve covers, why dont you make a small spacer under each valve cover just 1/2-3/4 "tall. This will keep clean air in your engine and not be obvious. Done right and painted engine color it would barely be noticeable yet keep the inside of your emgine clean.
     
  23. Terrible80
    Joined: Oct 1, 2010
    Posts: 730

    Terrible80
    ALLIANCE MEMBER

    Could you just cap the new oil fill, put a small tee out the side up to the rear of your air cleaner?

    Sent from my LG-TP450 using The H.A.M.B. mobile app
     
    Old wolf likes this.
  24. J53
    Joined: Aug 8, 2005
    Posts: 225

    J53
    Member
    from WI


    That's what I did- Bought a set of 1" valve cover spacers from Summit, drilled and tapped for a brass fitting, made a baffle for the inside that conforms to the inside shape of the finned Cal Custom valve cover (pulls dirty air from high up inside under valve cover), and hooked up a PCV valve to the center carb on the tri-power setup.
    My set-up;
    '69 327 (no road draft tube)
    Edelbrock tri-power intake (no provision for PCV and I wasn't crazy about drilling it)
    Finned valve covers (not drilling them!)
    Oil fill tube with breather cap

    IMG_2002.JPG

    Not 100% positive that this will be trouble free, but so far so good.
     
  25. DDDenny
    Joined: Feb 6, 2015
    Posts: 13,076

    DDDenny
    Member
    from oregon

    I know I've been away from the game for a while but what's that big latch hook for?
     
  26. Sheep Dip
    Joined: Dec 29, 2010
    Posts: 1,572

    Sheep Dip
    Member
    from Central Ca

    Read it again
     
  27. It don't make a ounce of difference if the PCV is at the front or rear of the engine or in a valve cover. And the same goes for the oil fill vent tube. I had a 66 chevelle 327 the PCV valve screwed into the oil fill tube. that oil fill had a non vented cap. and a steel one inch pipe ran from the back of the block and attached to the air cleaner housing. What the OP suggested will work just fine. A PCV doesn't reduce HP and don't decrease fuel economy. It will remove condensation and unburned combustion gasses that escape past the rings. It will make the engine last longer.
     
  28. DDDenny
    Joined: Feb 6, 2015
    Posts: 13,076

    DDDenny
    Member
    from oregon

    Like this, kinda.
    [​IMG]

    [​IMG]


    [​IMG]


    [​IMG]
     
  29. yes exactly like that. I fail to understand why folks overthink something as simple as a PCV system.
     
  30. J53
    Joined: Aug 8, 2005
    Posts: 225

    J53
    Member
    from WI


    So tell me then, if you don't have a road draft tube (they got rid of those for '69) and you have a oil fill tube without the PCV bung, and you don't want to drill your valve covers- how would you do it? I suppose if I didn't want to think it through and take the easy way out I could just settle for that ugly hose hanging out there. There are a ton of ways to route a PCV without "overthinking" anything. With a little creativity you can hide it in plain sight...

    IMG_2443.JPG
     

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