Technical Information
Installation Tips

Soak the rockers in 30 weight oil for ½ hour. Molly coat roller tips and the ball tip on the adjuster. Pushrod length adjuster should not exceed more than 2 threads out of the bottom of the rocker arm. Do not exceed 20 ft/lbs torque when locking adjuster in place.



Valve Cover Clearance

Most applications will not clear stock valve covers. Follow this procedure before installing valve covers and starting the engine:
Disconnect the coil, place the valve cover in position without gaskets. Hold it in place with your hand. Ask your assistant to turn over the engine several times by engaging the starter motor. If the rockers are hitting the valve covers, you will feel the cover move.

Additional clearance may be gained using taller aftermarket valve covers.



Length of Pushrod

Pushrod length is determined by several factors and should be established for each specific application. Examples: Smaller circumference cam with higher lift lobes = longer pushrods Resurfaced head or decked block = shorter pushrods Angle milling head = longer pushrods taller than stock valve stems = shorter pushrods



Valve Lash Settings

Follow cam manufacturer guidelines. Each application will vary. Hydraulic cams with stock rocker arms normally require 1 full turn tighter
from zero lash (no clatter). Roller rocker arms should be tightened no more than ½ turn from zero lash.



Changing Rocker Arm Ratios

The amount of additional lift at the valve will be determined initially by the amount of cam lobe lift.
If lift with a 1.5:1 rocker is 0.600 at the valve, then lift with a 1.6:1 rocker will be 0.640.
Use this simple formula: 0.600/1.5:1 = 0.400 (cam lobe lift) x 1.6:1 = 0.640 (gross lift). Lift increase = 0.040



Broken Rocker Arm

Typically, rocker arm breakage is due to another problem. However, any breakage that is due to manufacturing defects
and not abuse will be replaced or repaired. This excludes any rocker arm modified from its original state.

If you need further technical help email - tech@harlandsharp.com