1.5 vs. 1.6 Roller Rockers

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

  1. 70lt1z28

    70lt1z28 Veteran Member Gold Member

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    Beavercreek, Ohio, USA
    Need to also check the pushrod hole through the head. Many times it needs opened up. The 1.6 rockers move the pushrod closer to the stud. This is an issue with stock heads and you should be ok with aftermarket aluminum heads but it never hurts to check.
     
  2. COPO

    COPO Veteran Member Lifetime Gold Member

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    Sep 15, 1999
    Ontario, Canada
    If your springs, retainers and locks are not the best then expect breakage from the locks, and parts flying under the valve cover.
     
  3. SS Performance

    SS Performance Member

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    Nov 17, 2016
    If your springs aren't designed for the additional lift you could experience coil bind.

    Also depending on how much lift you have piston to valve clearance could be a problem.

    Just do your research and some math and you should be fine.
     
  4. 1980RS

    1980RS Veteran Member

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    Jun 17, 2006
    Bingo!, the force is strong with this one.
     
    slayer021175666 likes this.
  5. SS Performance

    SS Performance Member

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    Nov 17, 2016
    I don't buy this. a 1.6 ratio rock allows you to get more lift and a bit more duration and not increasing the ramp speeds on the cam lobe. This provides better lifter cam contact. This is more important with flat tappet lifters than roller lifters.
     
  6. slayer021175666

    slayer021175666 Veteran Member

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    Idaho
    Bad lobe contact is springs and/or hydraulic pressure loss. Not, rocker arm ratio.
     
  7. djorgensen3

    djorgensen3 Veteran Member

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    Oct 15, 2009
    Peoria, Az
    I'm fairly certain race teams keep different ratio rockers on the shelf to help tune for certain locations. They can use them for altitude or track types or even class rules that only allow certain cam specs. I wouldn't necessarily call it a band aid for poor cam choice. It is just another tuning aid.
     
  8. G72Zed

    G72Zed Veteran Member

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    Sep 8, 2015
    Canada
    From what I used, you can get SBC rockers in ratios from 1.35 "break in" and I've adjusted some in the 1.85 range, and there's higher ratios. It has more to do with opening/closing intensity (lift per degree) and the added lift, rather than the effect on duration. Given your info, I would stick with a 1.5 rocker, but upgrade to a 7/16 stud.
     
  9. SS Performance

    SS Performance Member

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    Nov 17, 2016
    You missed my point completely. A higher ratio rocker arm allows more lift and duration for the same lobe profile. Ramp speed and angle causes all sorts of problems. To over come those problems you run higher pressure springs. This causes additional problems. To avoid these problems you run a higher ratio rocker.

    Not a band aide fix. A designed/engineered solution to avoid other issues. If you look at some of the engines built in the engine masters challenge you will see some very high ratio rocker arms. These engines are not built by bench racers but master engine builders that take every factor into account when designing the engines.

    Also it's a hell of a lot easier to change some rocker arms than a cam. So if that's what you want to do go for it. Just do the math and check the clearances first.
     
  10. slayer021175666

    slayer021175666 Veteran Member

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    Feb 29, 2016
    Idaho
    To the OP:
    Now look what you did!:D
     

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