How to check rocker arm ratio?

Discussion in 'Manton Push Rods Top Alcohol Tech Questions' started by KMS, Jun 30, 2005.

  1. KMS

    KMS New Member

    Nov 24, 2003
    Likes Received:
    How can you tell whether you have 1.5,1.6 or 1.7 rockers for a hemi? Any know of a way to measure?
  2. Adam Culpepper

    Adam Culpepper Small Fry

    May 10, 2005
    Likes Received:
    on the engine, you can put a dial indicator on the lifter and measure the lift on the lobe, then install the rocker and measure the lift at the valve via a dial indicator on the retainer. if you stuff a rag or something around the pushrod hole, to keep the pushrod inline with the lifter, you can measure directly off the pushrod.

    or, if youre patient enough, you can measure the distance between the center of the trunnion on the rocker to the center of the pushrod cup/adjuster/whatever. then measure the distance from the c/l of the trunion to the center of the roller tip that touches the valve. divide these two measurements, and you can determine the rocker ratio. depending on how deep the pushrod cup is, you can sometimes get a ratio that seems a little bit off, but it should be close.
  3. DQUES

    DQUES Member

    May 20, 2004
    Likes Received:
    I am not sure how to tell the stageV rockers from one another just eyeballing them . If the engine is assembled you can check the lift at the valve and then try dividing that # by 1.7 , 1.6, or 1.5 and see which ratio matches your actual cam lobe lift . For example a typical hemi camshaft has .500 lobe lift so if you measured .850 at the valve then divided it by 1.7 you would have .500

    1.5 x .500 = .750 valve lift
    1.6 x .500 = .800
    1.7 x .500 = .850

    Don't be suprised if the actual lift at the valve is a little different from what it should be .

Share This Page