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  • Charles Nix
    Apprentice
    • Apr 5 2012
    • 55

    352 blowby

    Any one know of a quick fix to stop oil blowing back through oil filler tube? I am getting oil on my valve cover and have to clean it up every time after I drive it. I have a 352 in my 60 Tbird with a working PCV valve. The valve is located at the back of the block and connects to the base of the Edelbrock carb. Engine runs good with lots of power, no smoke. Don't have the money to do extensive motor work at this time. Ideas/suggestions would be appreciated. Thanks.
  • DKheld
    Super-Experienced
    • Aug 27 2008
    • 1583

    #2
    I tried a set up similar to yours. Have a hose from the back of the intake (at the outlet for the old road draft tube), a vented (for fresh air intake) oil filler cap with a hose outlet - ran the two hoses and connected them via a T to a hole punched in the air cleaner with one of the later internal style fiber filters. Increasing the size of the hose to 5/8 helped but still had oil bypassing at the filler tube cap.

    Blew the rear main seal this fall - probably won't need any of it on the rebuilt engine I am installing. Sorry - guess about all I can tell you is one method that didn't work.

    Good luck,
    Eric

    edit - yeah Dave - we're at it again - looking at the same post without knowing (twilight zone music playing)
    Last edited by DKheld; December 26, 2012, 05:26 PM.

    Comment

    • simplyconnected
      Administrator
      • May 26 2009
      • 8778

      #3
      Rather than trying to stop it, why not run it back into your air cleaner?

      There are passive crankcase vent systems that use an oil filler cap with a tube on the side for this purpose. I'm fimiliar with the caps that twist into a valve cover hole, so there should be caps for oil filler tubes as well. They should have metal oil-catcher mesh-material on the inside but no surrounding holes on the bottom. If you can't find one, make a fitting to adapt to your 'snorkel' hose.

      Get an old air cleaner and fashion a hole and filter element on the outside of the main air cleaner. Most auto parts stores have the plastic replacement parts.

      If you're already running pcv (which actively sucks vapors using manifold vacuum) and the blowby is so bad that it is spewing oil out the filler, it's hard to believe your engine doesn't burn oil.

      Check your oil pressures, just to be sure.

      Oil consumption only comes from two sources; piston rings and valve guides. Blowby comes from piston rings with huge gaps.

      Edit: Sorry Eric, I didn't see your post, first. - Dave
      Member, Sons of the American Revolution

      CLICK HERE to see my custom hydraulic roller 390 FE build.

      "We've got to pause and ask ourselves: How much clean air do we need?"
      --Lee Iacocca

      From: Royal Oak, Michigan

      Comment

      • cdhowell
        Apprentice
        • Jun 15 2011
        • 79

        #4
        Route your hose into a catch can. Similar to a vacuum style brake bleeder. Just remember to empty it on occasion.

        Comment

        • Anders
          Super-Experienced
          • Jan 19 2008
          • 2213

          #5
          I did it like simplyconnected describes it. I bought a Oil filler with an extra route out and connected a hose there and into the Air cleaner ( inside the filter ). Since that day, no oil anywhere in the engine bay, or under the car
          sigpic..."Lil darling Ruth":)
          http://www.tbirdregistry.com/#33158

          Comment

          • KULTULZ

            #6
            Are you sure the PCV is operational?

            Can you post photos?

            Comment

            • DKheld
              Super-Experienced
              • Aug 27 2008
              • 1583

              #7
              Ah ha!

              Had forgotten about my brother-in-law having the same trouble on his '57 MGA. He did exactly as cdhowell suggested. The catch can was pipped back to the draft tube (also present on the MG) and added some screening inside. His catch can had a drain on the bottom to empty it every now and then. Worked great.

              Eric

              Comment

              • Charles Nix
                Apprentice
                • Apr 5 2012
                • 55

                #8
                blowby

                Thanks for all the suggestions........will try to rig a catch can connected to the vent cap with a fitting and hose. Is that the general idea???

                Comment

                • simplyconnected
                  Administrator
                  • May 26 2009
                  • 8778

                  #9
                  All engines produce some blowby. As rings, cylinders and pisons wear, blowby increases.

                  There's a few things going on with a lot of blowby. It can become so much and flow so violent that it carries liquid oil with it. If the oil in your catch can doesn't coalesce (separate), liquid oil will escape and run all over your engine or it will be sucked into your carburetor.

                  If blowby becomes this bad, an engine overhaul will soon be in the offing because your plugs will load with oil deposits and foul frequently.

                  An ideal catch can includes a co**** mesh for the oil to condense, and a way for the liquid to return to your oil pan. If there is no return, it must be drained manually.

                  The top of your catch can should include a hose that attaches to your air cleaner, before the filter, so the fumes can be reburned.
                  Cars in the '60s and '70s used this method for (passive) crankcase ventillaton.

                  This is a balancing act. The fumes go up and the liquid goes down. If the crankcase develops too much pressure, oil will come out the path of least resistance: oil seals and cork gaskets. If the fumes carry too much oil, plugs will foul and exhaust smoke takes over.

                  Hope this helps. - Dave
                  Member, Sons of the American Revolution

                  CLICK HERE to see my custom hydraulic roller 390 FE build.

                  "We've got to pause and ask ourselves: How much clean air do we need?"
                  --Lee Iacocca

                  From: Royal Oak, Michigan

                  Comment

                  • redneck
                    Apprentice
                    • Aug 3 2009
                    • 37

                    #10
                    Hey Guys:
                    I solved the blow by like others have said by picking up an oil filler cap with a hose attachment and ran the hose to the air cleaner. No problem with oil film in the engine compartment or oil smoke coming out my hood scoop at the stop light.
                    My 2 cents worth.
                    Redneck in N. Minnesota

                    Comment

                    • Charles Nix
                      Apprentice
                      • Apr 5 2012
                      • 55

                      #11
                      Problem solved -envalve installed

                      I ran across a product on the internet called a "envalve". It replaces the PCV valve and was guaranteed to stop blowby (my car engine had been converted to a open PCV system before I bought it). So, for $50.00 I thought it was worth a try. I installed it last week and have had absolutely no blowby since. I'm not an engineer, so can't say how or why it works. However, I did have to convert my open PCV system to a closed system during install or the product would not operate properly according to the install instructions that came with the valve. Anyway, my car instantly ran smoother and idled better. After a few 20 mile trips around town and on the freeway, NO blowby. Just wanted to pass this information along-hope this can help someone in the future. Thank you all for your suggestions.

                      Comment

                      • DKheld
                        Super-Experienced
                        • Aug 27 2008
                        • 1583

                        #12
                        Charles - thanks for posting your solution. Never heard of the En-valve but will definitely consider it for future needs.

                        Eric

                        Here's a link to their web site for anyone interested.

                        Comment

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