1.5 vs. 1.6 Roller Rockers

Discussion in 'Engine Topic' started by iraqivet, Jan 24, 2018.

  1. iraqivet

    iraqivet Veteran Member Lifetime Gold Member

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    Nov 7, 2012
    Hobart, Indiana
    My son is studying mechanical engineering at Purdue and is currently a Junior. I'm assembling my SBC with Roller rockers on aluminum heads. I'm not familiar with the different ration aspects are. So I asked him. He told me the 1.6 will stay open a little longer for better flow. I see the math but have never installed roller rockers on an engine, let alone aluminum heads. Stock Edelbrock Pro Flow 3, Roller cam with same duration as factory (1980 Z-28) but with 10:1 pistons. Am I missing something or am I making this way too complicated? Z is going to be a cruiser, not a missile. Any help or suggestions would be great. I need to get this thing finished!
     
  2. Camaro16

    Camaro16 Veteran Member

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    Oct 22, 2006
    carthage ny
    If you look on YouTube engine masters just did this test
     
  3. Camaro16

    Camaro16 Veteran Member

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    Oct 22, 2006
    carthage ny
    On YouTube there is a video on this by engine masters. Real world dyno results.
     
  4. slayer021175666

    slayer021175666 Veteran Member

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    Feb 29, 2016
    Idaho
    To my knowledge, 1.6 gives higher lift. Duration is determined by the cam lobe shape.
     
  5. 70lt1z28

    70lt1z28 Veteran Member Gold Member

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    Oct 3, 1999
    Beavercreek, Ohio, USA
    Duration would also I think increase, but only very little. The ratio essentially magnifies what the lobe is doing. If you measure duration say at 0.050 lift, it gets there earlier in cam rotation when it opens and the same thing on the back side of the lobe. I think this is less of an effect on performance than lift in most cases.
    The engine masters video is good. Opened my eyes on the rests of roller rockers compared to stamped steel etc.
     
  6. iraqivet

    iraqivet Veteran Member Lifetime Gold Member

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    Nov 7, 2012
    Hobart, Indiana
    Thanks. I'll watch the video!
     
  7. larrylarry

    larrylarry Veteran Member

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    Dec 22, 2011
    San Antonio Tx
    I’d suggest that you put the 1.6 rockers on the intake side only & 1.5’s on the exhaust side. Normally the exhaust doesn’t need any extra help. Just wondering if your using different length push rods cause that’ll change when going with a roller cam.
     
  8. slayer021175666

    slayer021175666 Veteran Member

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    Feb 29, 2016
    Idaho
    Another point here:
    All the smartest guys say 1.6s are a "band-aid" for improper Cam selection. If you choose the right Cam, you don't need 1.6 rockers. 1.6s mess with the geometry a bit, too. That's no bueno!
     
  9. CorkyE

    CorkyE Veteran Member Lifetime Gold Member

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    Nov 4, 2004
    Ringgold, GA
    Got a link, I couldn't find it. Likely just me.
     

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