EXHAUST PUSHROD, TWINS, PRE ENGINE NUMBER 125871,

SOLID ALLOY BODY, STEEL ENDS.  MODELS 77, 99, 650/99, 750 ATLAS PRIOR TO ENGINE NUMBER 125871.  EXHAUST.

ORIGINALLY THE PUSHRODS USED ON THE TWINS WOULD BE SOLID ALLOY WITH STEEL ENDS, THESE THEN EVOLVED INTO A SPECIAL RENOLDS ALLOY HOLLOW TUBE.  (FIRST ARE PARALLEL, SECOND BARREL SHAPED), UNFORTUNATELY BY 1975 THE RENOLD COLD DRAWN TUBE BECAME UNAVAILABLE AND THE CAST PRODUCTION PUSHRODS ALONG WITH THE ALLOY ONES AVAILABLE TODAY WOULD RETAIN THE 'BARREL' SHAPE BUT ARE ACTUALLY SOLID.  THE STEEL PUSHRODS WHILST BEING HOLLOW ARE STILL HEAVIER THAN THE SOLID ALLOY PUSHRODS. THEIR ADVANTAGE IS DERIVED FROM THE FACT THAT THEY ARE SUBSTANTIALLY STRONGER AND WILL ALLOW THE VALVE TO FOLLOW THE THEORETICAL TIMING DICTATED BY THE CAMSHAFT.  AN ADVANTAGE UNLIKELY TO BE NOTICEABLE WHEN USING LOW/STANDARD LIFT CAMS AT LOW OR MEDIUM RPM'S.  ULTIMATELY CORRECT GEOMETRY CAN ONLY BE ACHIEVED BY DOING A PRELIMINARY ASSEMBLY AND OBSERVING THE SWEEP OF THE ROCKER ADJUSTER ACROSS THE VALVE TIP AS THE VALVE IS OPENED.  THERE ARE MANY VARIABLES THAT WILL AFFECT THIS AND IDEALLY AN OLD PUSHROD SHOULD BE USED AND EXAMINED IN OPERATION USED TO ESTABLISH THE CORRECT LENGTH OF THE PUSHROD TO OBTAIN AN ADJUSTER SWEEP THAT STARTS AND FINISHES AT APPROXIMATELY EQUAL DISTANCE FROM THE CENTRE LINE OF THE VALVE.

NOMINAL LENGTH: 7.416" (188MM)
OUTSIDE DIAMETER: 3/8"
WEIGHT: 42G