slant 6 oil weight

Slant 6 Engines

  1. QuickDart360

    QuickDart360 Well-Known Member

    Messages:
    1,031
    Likes Received:
    340
    Joined:
    Apr 5, 2014
    Location:
    San Antonio
    Local Time:
    4:39 PM
    I guess my question is that, will 10-30 be good enough to lubricate a bit stiffer valve springs crane springs similiar to the mopar red 340 springs. Also cam is the loved and hated 292 mopar purple grind. I live in San Antonio,Texas where it gets toasty in summer and winter is mild. Or 10-40 could be a better choice? My driving is for the most part "normal" with spirited jaunts here and there. My engine/bearing clearances are factory. Oil pump is stock pressure/flow. Windage tray and oil slinger are only things I added.
     
  2. fjr

    fjr Well-Known Member

    Messages:
    165
    Likes Received:
    26
    Joined:
    Mar 31, 2006
    Local Time:
    5:39 PM
    I've upgraded to a high-lift, short-duration in my slant six and have been using 340 valve springs since 1987. I've always run 10W-30 except for the time I tried 15W-40. Any modern CK-4 heavy duty oil with the Ford WSS-M2C171-F1 approval should have enough ZDDP to protect your valve train. I would stay away from racing oils because they have less detergents than HDEOs, which means you'll need to change your oil a lot more often to minimize sludge formation.

    Unless your oil runs really hot, you'll get more flow to your bearings with a thinner oil (like 10W-30) than a thicker oil like (10W-40). Chrysler spec'ed 20W-40 oils for summer operation so I would go with a 15W-40 if your low temperatures rarely fall below +32°F. See Chrysler Oil Recommendations and Engine Wear.
     
  3. RustyRatRod

    RustyRatRod Weenie idiot loser. FABO Gold Member

    Messages:
    58,018
    Likes Received:
    28106
    Joined:
    Jun 7, 2010
    Location:
    Georgia
    Local Time:
    5:39 PM
    3 pages of charts graphs and hogwash. Almost as bad as the crankcase breather/pcv valve thread.
     
    • Agree Agree x 1
    • pt70

      pt70 Well-Known Member

      Messages:
      210
      Likes Received:
      124
      Joined:
      Aug 23, 2019
      Location:
      CT
      Local Time:
      5:39 PM
      From a 1976 Chrysler FSM---10w30 to 20w50 is recommended when the temperature is above 32F. ---- Straight 30 weight is also included.
       
    • C130 Chief

      C130 Chief Mechanical Genius

      Messages:
      3,013
      Likes Received:
      157
      Joined:
      Nov 23, 2005
      Location:
      Boise, ID
      Local Time:
      3:39 PM
      Rotella T-6 5w40... Just sayin
       
      • Thanks! Thanks! x 1
      • yellow rose

        yellow rose Doctor of Thinkology.

        Messages:
        19,999
        Likes Received:
        16100
        Joined:
        Jun 19, 2015
        Location:
        Living on the razors edge
        Local Time:
        2:39 PM
        All engine oil have to be SAE.

        For those who refuse to understand why synthetics are better you need to do some real research.
         
        Last edited: Feb 11, 2020
      • Killer6

        Killer6 Well-Known Member

        Messages:
        2,372
        Likes Received:
        771
        Joined:
        Mar 9, 2015
        Location:
        PA
        Local Time:
        4:39 PM
        Using that in the '87 Dak 3.9L & '96 GC ES 3.8L...........
         
      • 69a100

        69a100 Well-Known Member

        Messages:
        100
        Likes Received:
        44
        Joined:
        Jun 29, 2009
        Local Time:
        2:39 PM
         
      • MOPAROFFICIAL

        MOPAROFFICIAL Well-Known Member

        Messages:
        4,802
        Likes Received:
        3814
        Joined:
        Jun 1, 2016
        Location:
        Beach
        Local Time:
        2:39 PM
        0 weight.
         
      • dart19666

        dart19666 FABO Gold Member FABO Gold Member

        Messages:
        532
        Likes Received:
        270
        Joined:
        Jul 28, 2014
        Location:
        Sandy Eggo
        Local Time:
        2:39 PM
        Why not add my two cents so I can beat that horse a little more. Here at Crower we have tested so many oils I cant even keep track of it all anymore. But here are the top four that we have tested. Driven, Brad Penn, VR-1 and last but not least is Rotella T-4 & T-6 50-50 blend. I get asked all the time what do I use in my daily driver slant six and I use the 50-50 blend Rotella. I drive my car 50 miles a day on the freeway at 2,500 rpm and just changed to a 200 4r trans and that dropped it too 2,000rpm. I just pulled the engine to do a 30,000 mile inspection. Also to do some work with Fast Fish for a billet rear main seal housing to use with their one cut rear main seal. Horse has fully been beaten now. Ha ha ha ha ha
         
      • fjr

        fjr Well-Known Member

        Messages:
        165
        Likes Received:
        26
        Joined:
        Mar 31, 2006
        Local Time:
        5:39 PM
        Why are you mixing Rotella T-4 & T-6 into a 50-50 blend? And are you mixing the same grade?
         
      • dart19666

        dart19666 FABO Gold Member FABO Gold Member

        Messages:
        532
        Likes Received:
        270
        Joined:
        Jul 28, 2014
        Location:
        Sandy Eggo
        Local Time:
        2:39 PM
        Yes 50-50 blend of t4 and t6.
         
      • Charrlie_S

        Charrlie_S Well-Known Member

        Messages:
        2,763
        Likes Received:
        649
        Joined:
        Oct 17, 2005
        Location:
        Silver Springs, FL
        Local Time:
        5:39 PM
        I just can't understand why the need for designer oils in a slant six. Every slant six engine I have ever had, since 1974, whether stock or modified, got Parts store "house brand" 10w-30, and I have never had a oil related failure. Damm it ain't the space shuttle, and Unckel Sam ain't paying for it.
         
        • Agree Agree x 1
        • MOPAROFFICIAL

          MOPAROFFICIAL Well-Known Member

          Messages:
          4,802
          Likes Received:
          3814
          Joined:
          Jun 1, 2016
          Location:
          Beach
          Local Time:
          2:39 PM

          As with all motors
           
        • moparblood

          moparblood Well-Known Member

          Messages:
          137
          Likes Received:
          36
          Joined:
          Dec 24, 2014
          Location:
          n.y.
          Local Time:
          4:39 PM
          I can't believe i read all the threads.
          My worthless opinion= all /6's require oil to run. Sometimes Not!
          i guess vegetable oil Hasn't been tried!
           
        • zkx14

          zkx14 Duster De-ruster FABO Gold Member

          Messages:
          22,755
          Likes Received:
          15960
          Joined:
          Dec 23, 2012
          Location:
          South Central PA
          Local Time:
          5:39 PM
          I’d bet someone did it. Might not last long. Smell like fries. :thumbsup: :rofl:
           
        • zkx14

          zkx14 Duster De-ruster FABO Gold Member

          Messages:
          22,755
          Likes Received:
          15960
          Joined:
          Dec 23, 2012
          Location:
          South Central PA
          Local Time:
          5:39 PM
          We have some old machines at work. I try to figure out what oil they are supposed to have. But sometimes it comes to ‘any oil is better than no oil’ to keep them running.
           
        1. This site uses cookies to help personalize content, tailor your experience and to keep you logged in if you register.
          By continuing to use this site, you are consenting to our use of cookies.