Enter your username:
Do you want to login or register?
  • Forgot your password?

    Login / Register



    Page 1 of 2 1 2 LastLast
    Results 1 to 20 of 28
    1. #1
      Join Date
      Aug 2015
      Location
      NJ
      Posts
      282
      Country Flag: United States

      From blowing oil pan gasket to now blowing dipstick tube - help

      Been battling this for months. Have a brand new 572 custom built BB. Been back and forth with engine builder about this. Ran compression and leak down tests and results were exceptional - they did their job! Saw issues with the 7qt Milodon pans sealing and called them directly to address it accordingly. Had to pull the motor to pull the pan and didn't want to do it again so researched. During the oil pan issues, had a pcv on the passenger cover and one breather on the drivers cover. Upgraded to a pcv on the passenger back, breather on the drivers back, and a 12AN fitting on the front of each cover running to vented oil catch cans.. Well now that the pan is properly sealed, I am blowing the dipstick up about an inch and oil is trickling out of the tube. This is a street driven show car and was going to go the route of a vacuum pump, but read bad things for street use. Is that my last resort? Is something else going on here? Name:  20190525_134222.jpg
Views: 480
Size:  80.6 KB
      '68 Chevy Camaro Pro-tour ~ project DMENTD
      '57 Chevy 3100 Pro-tour pickup ~ under construction

    2. #2
      Join Date
      Jun 2012
      Location
      South Lyon, MI
      Posts
      1,217
      Country Flag: United States
      Does it blow out the dipstick under light loads and cruising, or only when you get on it hard?

      What is the compression ratio and horsepower?

    3. #3
      Join Date
      Aug 2015
      Location
      NJ
      Posts
      282
      Country Flag: United States
      Quote Originally Posted by cornfedbill View Post
      Does it blow out the dipstick under light loads and cruising, or only when you get on it hard?

      What is the compression ratio and horsepower?
      When you really get on it.

      11.5:1
      742 on dyno
      '68 Chevy Camaro Pro-tour ~ project DMENTD
      '57 Chevy 3100 Pro-tour pickup ~ under construction

    4. #4
      Join Date
      Nov 2006
      Location
      Mountain Springs, Texas
      Posts
      4,488
      Country Flag: United States
      PCV is too restrictive allowing pressure to build imho.

      Don
      1969 Camaro - LSA 6L90E AME sub/IRS
      1957 Buick Estate Wagon
      1959 El Camino - Ironworks frame
      1956 Cameo - full C5 suspension/drivetrain
      1959 Apache Fleetside

    5. #5
      Join Date
      Jun 2012
      Location
      South Lyon, MI
      Posts
      1,217
      Country Flag: United States
      You have blowby that is overwhelming the PCV. You will always have pressure past the rings under normal operation. This increases with cylinder pressures.

      Reducing the top ring gap can help as long as they don't make contact when they are hot.

      The quick solution is to increase flow of the crankcase breather system.

    6. #6
      Join Date
      Aug 2004
      Location
      NJ
      Posts
      1,293
      Country Flag: United States
      If you don't get a good answer here, may I suggest the Chevelle forums? It's been awhile since I've sold mine and have been active over there, but their were some really knowledgeable old school big block guys in that forum that could probably help you. They were pretty popular since a lot of guys used them to get their A-bodies moving!

      Good luck, sounds like a lot of fun you have their under the hood!

    7. #7
      Join Date
      Jun 2001
      Location
      Orlando, FL
      Posts
      10,603
      Country Flag: United States
      PCV and valve cover breather don't mix. You need to have engine vacuum pulling those vapors past the PCV valve and into the engine. And you need to have clean fresh air coming into the other side of the engine, typically from the engine air cleaner.

      At WOT, vacuum drops, and the PCV becomes ineffective. In that case, the clean fresh air path reverses and the blowby should go into the intake air path and burned by the engine that way. If you don't want oil going through those paths, you'll need catch cans.

      Hope that helps.
      John Parsons

      UnRivaled Rides -- Modern upgrades for your ride.

      UnRivaled Rides recent project -- LS9-powered 69 Camaro

    8. #8
      Join Date
      Jun 2012
      Location
      South Lyon, MI
      Posts
      1,217
      Country Flag: United States
      Quote Originally Posted by parsonsj View Post
      PCV and valve cover breather don't mix. You need to have engine vacuum pulling those vapors past the PCV valve and into the engine. And you need to have clean fresh air coming into the other side of the engine, typically from the engine air cleaner.

      At WOT, vacuum drops, and the PCV becomes ineffective. In that case, the clean fresh air path reverses and the blowby should go into the intake air path and burned by the engine that way. If you don't want oil going through those paths, you'll need catch cans.

      Hope that helps.
      What he said.

    9. #9
      Join Date
      Nov 2014
      Posts
      233
      Country Flag: United States
      I think Don is on point. 572 is a big engine and remember that for every revolution you move 572ci air thru the crank case. I just don't think a valve cover PCV valve will move enough air to keep from pressurizing the crankcase. vacuum pump will definitely take care of the problem, but do require some maintenance.

    10. #10
      Join Date
      Jun 2001
      Location
      Orlando, FL
      Posts
      10,603
      Country Flag: United States
      It's not true that you move 572ci of air through the crank case per revolution.

      The cylinders all share the same air volume in the crankcase, and so as one piston moves down (two actually, in a 90 degree V8) another piston is moving up. Crankcase air volume is relatively static. Increases in air volume are almost directly related to combustion gases getting past the rings and valve guides.
      John Parsons

      UnRivaled Rides -- Modern upgrades for your ride.

      UnRivaled Rides recent project -- LS9-powered 69 Camaro

    11. #11
      Join Date
      Aug 2015
      Location
      NJ
      Posts
      282
      Country Flag: United States
      Quote Originally Posted by dhutton View Post
      PCV is too restrictive allowing pressure to build imho.

      Don
      Even with the 3 other vents?
      '68 Chevy Camaro Pro-tour ~ project DMENTD
      '57 Chevy 3100 Pro-tour pickup ~ under construction

    12. #12
      Join Date
      Jun 2012
      Location
      South Lyon, MI
      Posts
      1,217
      Country Flag: United States
      Quote Originally Posted by parsonsj View Post
      It's not true that you move 572ci of air through the crank case per revolution.

      The cylinders all share the same air volume in the crankcase, and so as one piston moves down (two actually, in a 90 degree V8) another piston is moving up. Crankcase air volume is relatively static. Increases in air volume are almost directly related to combustion gases getting past the rings and valve guides.
      This is correct.

      The pressure in the crankcase is from blowby past the rings. This is normal and typically proportional to displacement and cylinder pressure. Zero gap rings are often used in high output large bore engines to minimize this.

      I suggest a change to the crankcase ventilation system. PCV may not be adequate.

    13. #13
      Join Date
      Aug 2015
      Location
      NJ
      Posts
      282
      Country Flag: United States
      Quote Originally Posted by parsonsj View Post
      PCV and valve cover breather don't mix. You need to have engine vacuum pulling those vapors past the PCV valve and into the engine. And you need to have clean fresh air coming into the other side of the engine, typically from the engine air cleaner.

      At WOT, vacuum drops, and the PCV becomes ineffective. In that case, the clean fresh air path reverses and the blowby should go into the intake air path and burned by the engine that way. If you don't want oil going through those paths, you'll need catch cans.

      Hope that helps.
      I have 2 vented catch cans now on either side of my radiator that the AN lines run to. Have no air cleaner, can't fit one under my hood. What else can I do to improve air flow or is a vac pump my only option?
      '68 Chevy Camaro Pro-tour ~ project DMENTD
      '57 Chevy 3100 Pro-tour pickup ~ under construction

    14. #14
      Join Date
      Aug 2015
      Location
      NJ
      Posts
      282
      Country Flag: United States
      Quote Originally Posted by cornfedbill View Post
      This is correct.

      The pressure in the crankcase is from blowby past the rings. This is normal and typically proportional to displacement and cylinder pressure. Zero gap rings are often used in high output large bore engines to minimize this.

      I suggest a change to the crankcase ventilation system. PCV may not be adequate.
      So do I ditch the pcv hooked to the back of the carb and add another breather to start amd add a vac pump after that if that doesn't work? Doubt regapping the rings is part of the warranty from the engine builder amd that is out of my league.
      '68 Chevy Camaro Pro-tour ~ project DMENTD
      '57 Chevy 3100 Pro-tour pickup ~ under construction

    15. #15
      Join Date
      Jun 2012
      Location
      South Lyon, MI
      Posts
      1,217
      Country Flag: United States
      Quote Originally Posted by pittpens24 View Post
      So do I ditch the pcv hooked to the back of the carb and add another breather to start amd add a vac pump after that if that doesn't work? Doubt regapping the rings is part of the warranty from the engine builder amd that is out of my league.
      I would look at breather systems with an oil catch can before going to a vacuum pump. If you keep the PCV connected to the carb, it should work under normal conditions. With larger breather tubes connected to oil catch cans or separators, the pressure should bleed out through the catch cans/separators under high load.

    16. #16
      Join Date
      Feb 2014
      Location
      Georgia
      Posts
      93
      Country Flag: United States
      Here's some good reading on CCV systems: https://www.shophemi.com/images/medi..._ccv_bible.pdf
      Take a look at the Stage 3 solution.
      Steve - 1970 Roadrunner


    17. #17
      Join Date
      Aug 2015
      Location
      NJ
      Posts
      282
      Country Flag: United States
      Quote Originally Posted by LemonTwisted View Post
      Here's some good reading on CCV systems: https://www.shophemi.com/images/medi..._ccv_bible.pdf
      Take a look at the Stage 3 solution.
      That is perfect ty! My only issue is I am carburated with no air cleaner. So where do I send the return lines? My only options are back of the carb and tapping into the back of the manifold

      '68 Chevy Camaro Pro-tour ~ project DMENTD
      '57 Chevy 3100 Pro-tour pickup ~ under construction


    18. #18
      Join Date
      Jun 2001
      Location
      Orlando, FL
      Posts
      10,603
      Country Flag: United States
      Quote Originally Posted by TL
      Here's some good reading on CCV systems: https://www.shophemi.com/images/medi..._ccv_bible.pdf
      That's a great resource, thanks for posting it.
      John Parsons

      UnRivaled Rides -- Modern upgrades for your ride.

      UnRivaled Rides recent project -- LS9-powered 69 Camaro

    19. #19
      Join Date
      Jun 2001
      Location
      Orlando, FL
      Posts
      10,603
      Country Flag: United States
      Quote Originally Posted by PP
      My only issue is I am carbureted with no air cleaner.
      No air cleaner? The whole notion of PCV is to move clean air into the crankcase to replace dirty air being removed by vacuum. Without an air cleaner... PCV is rather pointless. I suppose you use atmospheric air -- it's probably better for the engine than combustion air, but...
      John Parsons

      UnRivaled Rides -- Modern upgrades for your ride.

      UnRivaled Rides recent project -- LS9-powered 69 Camaro

    20. #20
      Join Date
      Sep 2013
      Location
      Houston, TX
      Posts
      246
      Country Flag: United States

      Wagner Adjustable PCV

      Would an adjustable PCV valve solve his problem? Here's a dual circuit adjustable one from Wagner.

      http://mewagner.com/?p=444

      Name:  WagnerPCV.jpg
Views: 355
Size:  13.5 KB
      Rodney Meyers
      72 Olds 442 Rest-mod clone

    Page 1 of 2 1 2 LastLast




    Advertise on Pro-Touring.com