verifying rocker ratios

Discussion in 'PSI Superchargers Tech Questions' started by James D, Mar 16, 2012.

  1. James D

    James D New Member

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    I have a set of stage v intakes scribed 1.70 and a set of kluff exhuast with no markings at all. Is there a way to check the ratio's by simply measuring?
     
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    James D, Mar 16, 2012
  2. Mike Canter

    Mike Canter Top Dragster
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    Get a dial indicator and a stand to hold it. Adjust the valve lash to zero. Put the dial indicator onto of the lash adjustment screw and rotate the engine until zero lift which means you are on the base circle of the cam and zero out the dial indicator. Now rotate the engine until you read the highest point and that is your total cam lift (should be same as on the cam card) and record it. Now move the dial indicator so it is on the lip of the retainer and turn the engine so the valve is fully closed and zero the indicator. Now rotate until valve is fully open and read the indicator and record it. That is now actual lift at the valve with the rocker arm ratio. Divide that actual valve lift by the actual cam lift and you will have the true rocker are ratio.
     
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    Mike Canter, Mar 17, 2012
  3. SoDak

    SoDak Active Member

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    I agree with the above, except for our T&D BBC rockers you have to use the real valve spring not a lightweight one. They build extra ratio into the rockers to compensate for flex!!! Mine calc'd out to 1.75 and they were stamped 1.70, I couldn't believe it. I called T&D and they told me this. I put the real spring back in and I lost .039" of valve lift:eek: which made the ratio calc right back to 1.7 like it should've been
     
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    SoDak, Mar 17, 2012

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