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Question on Non Baffled Valve Covers

Discussion in 'The Hokey Ass Message Board' started by Hdonlybob, Oct 27, 2010.

  1. Hdonlybob
    Joined: Feb 1, 2005
    Posts: 3,950

    Hdonlybob
    Member

    Last week I had some old M/T aluminum valve covers soda blasted to give to my son.
    When picking them up from the shop that did it, the owner told me never to use these without baffles. I asked why, as the Holly covers on my engine (see pic) do not have baffles......and he tells me that when using a PCV valve it will just suck oil out of that side, making engine use a lot of oil...
    So, should I block off my PVC outlet in my carb, and just use another vented cap on mine....or is this just a myth....
    Would appreciate any help.
    Thanks as usual,
    Bob :D
     

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  2. butch27
    Joined: Dec 10, 2004
    Posts: 2,847

    butch27
    Member

    No answer for you but I've got the same problem.
     
  3. carcrazyjohn
    Joined: Apr 16, 2008
    Posts: 4,844

    carcrazyjohn
    Member
    from trevose pa

    In my old Chevelle I ran them that way ,Just check your oil frequently ,But if using a high volume oil pump ,Baffle them....
     
  4. is it hard to put a baffle in it? so you can run a pcv .
     

  5. Hackerbilt
    Joined: Aug 13, 2001
    Posts: 6,250

    Hackerbilt
    Member

    A friend of mine ran covers with no baffle for the PCV and the car was an oil burner right away.
    His covers had bosses inside to add a sheetmetal baffle and once he added one it did the job. Nothing fancy...just something to deflect the oil away from the PCV inlet.
     
  6. Hdonlybob
    Joined: Feb 1, 2005
    Posts: 3,950

    Hdonlybob
    Member

    What is the disadvantage of not using a PVC valve, (block off he connection to the carb) and just venting thru the valve cover with an extra breather unit ?
     
  7. Chevy Gasser
    Joined: Jan 23, 2007
    Posts: 701

    Chevy Gasser
    Member

    I migged an aluminum plate below the holes in my M/T's and it stopped the smoking. There are rubber grommet/baffles that will sometimes work.
     
  8. RJP
    Joined: Oct 5, 2005
    Posts: 1,957

    RJP
    Member
    from PNW

    just use a pcv extender. Olds used them in the old days. Put the pcv out of the cover.
     
  9. 29nash
    Joined: Nov 6, 2008
    Posts: 4,544

    29nash
    BANNED
    from colorado

    I would fabricate a baffle and figure out a way to attach it. Get clues on how to position it from looking at covers with baffles.
     
  10. Hackerbilt
    Joined: Aug 13, 2001
    Posts: 6,250

    Hackerbilt
    Member

    Among other things, the PCV system helps remove moisture from the engine internals.
    The moisture condenses inside the block due to the heat/cool cycle.

    Go for a drive and let the engine get up to full operating temperature, the moisture inside the engine returns to vapor and gets sucked out the PCV into the intake where it gets burned up in the combustion process.

    No PCV and it just recondenses inside the engine and builds up over time, thus polluting the oil.

    Non PCV engines often have issues with this creamy sludge and I've seen it get to the point where the dipstick couldn't even be read due to the milkshake in the tube.
    PCV setup's offer no disadvantages and are one of the best "add-ons" ever devised for an engine.

    You might not NEED it to go for a drive...but you'll appreciate it for what it does to help keep your engine clean internally.
     
  11. Da' Bomb
    Joined: Apr 8, 2005
    Posts: 438

    Da' Bomb
    Member

    I went through the same thing with some Cal Custom valve covers....The oil dumping didn't happen until after I changed out cams and and went to roller rockers. I ended up adding baffels that cleared the rockers by about .05". Gees, what a mess until I figured out what was going on.....

    Pat
     
    pat59 likes this.
  12. Deuces
    Joined: Nov 3, 2009
    Posts: 20,930

    Deuces
    Member
    from Michigan

    Yeah! What he said! ^^^
     
  13. gimpyshotrods
    Joined: May 20, 2009
    Posts: 18,483

    gimpyshotrods
    ALLIANCE MEMBER

  14. The problem with the M/T and Holley valve covers is the "cut out" for ventilation is directly over the valve rockers and not between like the factory units. If you use breather caps you should be ok, but a vacuum system would be better. If you can, run a vent hose from the crankcase to the carb and use two breather caps to let air in.

    I drilled and tapped two holes in my M/T's and attached a flat plate to the bottom spaced off with some washers. This kept the oil out, but then you want to be sure that those screws don't back off. This approach will not work if you have exta tall valve train set up.
     
  15. Jalopy Joker
    Joined: Sep 3, 2006
    Posts: 27,223

    Jalopy Joker
    Member

    need baffles, or vent tube extenders like oval track racers use or use Moon, etc vents that attach to (upper) sides of V/C unless your intake manifold has a vent tube in it.
     
    old skoool likes this.
  16. missysdad1
    Joined: Dec 9, 2008
    Posts: 3,022

    missysdad1
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  17. tiredford
    Joined: Apr 6, 2009
    Posts: 535

    tiredford
    Member
    from Mo.

    I put some cheap chrome covers on a 460 Ford that had no baffles. It used a quart of oil every 100 miles. It sucked the oil right into the carb.
     
  18. 29nash
    Joined: Nov 6, 2008
    Posts: 4,544

    29nash
    BANNED
    from colorado

    Tying the word 'baffled' to a grommet don't make it a baffle.
     
  19. BOWTIE BROWN
    Joined: Mar 30, 2010
    Posts: 3,253

    BOWTIE BROWN
    Member

    i plan on using my MT covers , this has helped . Thanx guys.
     
  20. missysdad1
    Joined: Dec 9, 2008
    Posts: 3,022

    missysdad1
    ALLIANCE MEMBER

    They sure look like they will work. Perhaps someone with actual experience with these devices will chime in.

    Also, the opposet valve cover has to be vented to allow fresh air to enter in order for the PCV system to work properly.

    Failure to provide a fresh air inlet will cause a high vacuum inside the engine which would likely cause high oil consumption. A fairly low vacuum is all that is necessary to extract the vapor/blow-by in a healthy engine.

    :)
     
  21. Hdonlybob
    Joined: Feb 1, 2005
    Posts: 3,950

    Hdonlybob
    Member

    Wow....usual great info here...
    So, I have not yet blocked off the old vent tube on the back of my 283 block ('65) and if I understand correctly maybe I should just make an adaptor and run a hose from it directly to the carb where the PCV valve connects, and go with another vented cap on the valve cover?
    Make sense? I think that would give me the cleanest and most positive venting..
    What you say???
    Bob
     
    swade41 likes this.
  22. That would be the design used AFTER the draft tubes were removed. Most engines had just one breather cap on the intake oil fill tube. Your idea of two breather caps is even better.
     
  23. missysdad1
    Joined: Dec 9, 2008
    Posts: 3,022

    missysdad1
    ALLIANCE MEMBER

    These early '60s Chevy engines used a hose fitting adapter - looks like a cone with a hose fitting coming out of it, bolt runs down through the center - which allows this to happen. There is a baffle - looks like a tomato juice can - inside the valley under the intake to keep oil from being sucked out through the hose.

    Check to be sure the tomato juice can is still in your engine before using the cast-in rear block opening as a PCV connection. Otherwise you'll end up sucking oil through this opening and into the carburetor.

    The front air intake was though the oil filler tube at the front of the intake. If your intake does not have the vented oil filler tube a valve cover vent will do.

    To work best the air flow should move across the engine, front to back or side to side. A PCV valve in one end of a valve cover with the fresh air intake in the other end of same valve cover won't get the job done.
     
  24. Mr48chev
    Joined: Dec 28, 2007
    Posts: 29,782

    Mr48chev
    ALLIANCE MEMBER

    Along with what Hackerbuilt said about getting the condensation out of the engine it also helps relieve the pressure build up that would cause oil leaks if the engine wasn't vented and blow oil out the breaters if you just ran a pair of breathers and no pcv valve.
     
  25. gimpyshotrods
    Joined: May 20, 2009
    Posts: 18,483

    gimpyshotrods
    ALLIANCE MEMBER

    Well, I have installed over 30 of these in either non-baffled valve covers, or in a hole drilled in the back of a manifold, including two of my own rides, and they appear to work just fine.

    Anybody have a data set that indicates otherwise? Data beats anecdote every time.

    No, they won't work if if the hole is right over the rocker. If the hole is in the "factory" position, they clear the rockers just fine. Yes, there has to be a fresh air inlet somewhere else, like the other valve cover.
     
  26. Hmmm,Ive got a 65 327 in my 27 ,it has a edelbrock c-28 intake (2x4),the rear road draft tube is capped with a freeze plug and Im using no name,no hole cal custom valve covers.The only problem I ever have is some oil on the windshield(the fill tube is a chrome one without the baffle,but Im going to try the baffled breather to an overflow behind the shell hopefully it wont be so messy."baffeling mystery"
     
  27. RustyNCA
    Joined: Feb 18, 2009
    Posts: 406

    RustyNCA
    Member

    So if you are running the cal custom valve covers with moon breathers and a vented oil filer cap only, running a pvc valve will solve the problem with blow by and oil on the windscreen?

    Second question is where to run it if need be? The 97's don't have vacuum ports on them.

    Thanks
    RustyNCA
     
  28. missysdad1
    Joined: Dec 9, 2008
    Posts: 3,022

    missysdad1
    ALLIANCE MEMBER

    You can do that if you want, but the motor will still puke oil...you'll just be catching it in a can rather than on your windshield.

    Pressure is created in the engine by blowby during operation. This pressure has to go somewhere...as does the water vapor, combustion byproducts and oil "mist"...and if you don't provide a path out it will find its own way, as you have discovered.

    But, as has been mentioned already, even with a road draft tube, vented valve covers or open oil fill tube, the water vapor will condense in the crankcase and the combustion byproducts will mix with the oil unless they are pulled out and burned along with the fuel/air mixture under the carburetor.

    A functioning PCV system will keep your oil and the inside of your motor much, much cleaner and will eliminate road draft "fumes" and oily windshields in cases like yours. As has also been mentioned, there is no performance or other downside to a properly functioning PCV system.

    Since you've already got a block with a cast-in boss for the rear PCV, why not knock the freeze plug out and make it functional? You'll need to be sure in internal "tomato can" baffle is still in place (if not they are easily found and installed) and find an OEM rear breather "cap" assembly, but the effort would certainly be worthwhile.

    Your motor...and your windshield...will love you if you do.

    :)
     
  29. missysdad1
    Joined: Dec 9, 2008
    Posts: 3,022

    missysdad1
    ALLIANCE MEMBER

    Yes. You'll need to block off the valve cover breathers and use the vented oil filler cap only as a fresh air inlet.

    You may need to create a vacuum source below the butterflies if you don't already have one. You can use an under-carburetor plate or drill and tap the manifold itself in the area of the carburetor base.

    Depending upon your engine you may need to create a baffled access to the crankcase as well. This can be done in a number of ways if the factory block does not provide one as the early '60s Chevy V8s do, as discussed above.

    Be sure to use a PCV valve, not just an open tube, in the line from the crankcase to the under-carburetor vacuum source. The valve prevents "flash back" into the crankcase in the case of a backfire.

    :)
     
    Last edited: Oct 28, 2010
  30. I removed the baffle under the stock intake...two different intakes would not clear,would hit the (TOMATO PASTE CAN)baffle.The small dia air cleaners will not allow for tube to be plumbed beneath them
     

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