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  1. #1
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    Default Roller rockets required for roller cam?

    The TA catalog says the roller cams require roller rockers. Just curious , why?
    64 Skylark Convertible
    462 w/ Stage 2 heads, TA 212 cam, B4B intake
    TKO600
    3.73 12 Bolt w/ TruTrac and Moser axles

  2. #2
    Join Date
    Dec 2006
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    1,858

    Default Re: Roller rockets required for roller cam?

    Quote Originally Posted by BillA View Post
    The TA catalog says the roller cams require roller rockers. Just curious , why?
    Strength, durability and adjustability.

  3. #3
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    Nov 2013
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    Default Re: Roller rockets required for roller cam?

    There's a practical limit to how much lift and spring pressure a stock rocker will tolerate.
    Another issue that's greatly compounded is when the geometry isn't good enough to roll the radius of a stock type rocker across the valve stem without scrubbing it, causing severe wear and guide problems.
    A roller doesn't scrub the tips.

  4. #4
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    Default Re: Roller rockets required for roller cam?

    Quote Originally Posted by 8ad-f85 View Post
    There's a practical limit to how much lift and spring pressure a stock rocker will tolerate.
    Another issue that's greatly compounded is when the geometry isn't good enough to roll the radius of a stock type rocker across the valve stem without scrubbing it, causing severe wear and guide problems.
    A roller doesn't scrub the tips.
    Makes sense. The OEM's have been using roller cams without roller rockers for 30 years so I was just curious why TA roller cams required them. Thanks.
    64 Skylark Convertible
    462 w/ Stage 2 heads, TA 212 cam, B4B intake
    TKO600
    3.73 12 Bolt w/ TruTrac and Moser axles

  5. #5
    Join Date
    Nov 2013
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    Default Re: Roller rockets required for roller cam?

    The OEM's have a blueprint they follow with consistent deck height and pushrod length allowing the radius shoe to roll across without scrubbing.
    There's almost no way for an aftermarket manufacturer to cover every possible configuration of parts selection or tolerance stack up and guess at what a rebuilder type machine shop might do to the castings.

    The specs are so much milder on OEM rollers than aftermarket performance cams that even a carefully designed show type rocker would be a weird looking piece to both handle the arc and the increased stress levels.
    A roller tip is so much easier to make from a manufacturing standpoint than to properly harden a goofy, inexpensive OEM (but modified) copy.
    I'm guessing that since there isn't such a product on the market proven to both work properly AND survive, that TA is specifically referring to the stock Buick piece, saying it is NOT adequate for those cams.

  6. #6
    Join Date
    May 2002
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    Default Re: Roller rockets required for roller cam?

    Quote Originally Posted by 8ad-f85 View Post
    A roller doesn't scrub the tips.
    Sure it does. The roller is much too small to actually roll on the valve tip.

    Roller rockers are needed to provide some adjustment if the pushrods aren't chosen appropriately, or to allow lash adjustment on solid lifters.
    Roller rockers tend to be stronger than the OEM offerings.
    Roller rockers can reduce oil temperature IF THE VALVE SPRINGS ARE STIFF.
    Roller rockers generate a fair amount of profit.
    OEM rockers are almost certainly worn-out unless recently replaced.

    Take a look at the "roller rockers" on many of the higher-performance LS engines: They have a roller pivot at the stud, but a "shoe" at the valve tip.

  7. #7
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    Dec 2013
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    Sacramento, CA
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    1,030

    Default Re: Roller rockets required for roller cam?

    Quote Originally Posted by Schurkey View Post
    Sure it does. The roller is much too small to actually roll on the valve tip.

    Roller rockers are needed to provide some adjustment if the pushrods aren't chosen appropriately, or to allow lash adjustment on solid lifters.
    Roller rockers tend to be stronger than the OEM offerings.
    Roller rockers can reduce oil temperature IF THE VALVE SPRINGS ARE STIFF.
    Roller rockers generate a fair amount of profit.
    OEM rockers are almost certainly worn-out unless recently replaced.

    Take a look at the "roller rockers" on many of the higher-performance LS engines: They have a roller pivot at the stud, but a "shoe" at the valve tip.
    But what about a roller rocker with a roller tip. The rocker has needle bearings but not the roller. we need to try this on a set of bearinged roller roller bearing rockers.
    But i have turned my motor on engin stand and watched the rollers, they roll.. but not much. With good geometry they really shouldnt roll much. I would like to watch this on a runing engine with a timing lite.
    Anson Favalessa

  8. #8
    Join Date
    Nov 2013
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    1,582

    Default Re: Roller rockets required for roller cam?

    I think they swivel and skate a little bit.
    I know if you have some roller tips that are drilled eccentric with a lashed solid cam, they seem to find the spot with the most lash and quickly hammer out shrapneled parts.

  9. #9
    Join Date
    Feb 2002
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    Garfield Hts, Ohio
    Posts
    4,850

    Default Re: Roller rockets required for roller cam?

    I've been running TA's 1.6 rollers on my 350 GS since 1991 or so.
    Absolutely no wear pattern on the roller tip or the valve stem.
    Another reason TA probably suggests roller rockers is the very abrupt and quick valve action associated with a roller cams profile, which would cover all the reasons about durability mentioned above
    71 GS 350 (mine) Best so far 13.65 @ 98.84 mph
    SP3 track testing to resume in 2016!
    413 cam going away, switching to TA roller, starting again with Stage 1 and Q-Jet, then to SP3 and AED
    87 Grand National (Hers) no passes yet
    00 Monte Carlo
    2001 GMC Safari AWD
    2007 Mazda 3
    Ranch house with 4 dogs and a cat

  10. #10
    Join Date
    Feb 2002
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    Louisville,Kentucky 40229
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    Default Re: Roller rockets required for roller cam?

    Quote Originally Posted by BillA View Post
    The TA catalog says the roller cams require roller rockers. Just curious , why?

    Spring pressure is main reason and amount of lift is the other.
    Michael Evans

    "Universal means the part universally does not fit anything until you make it"


    Next Buick project...........1987 T-Type

 

 

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