TAPPET CLEARANCE SHOULD BE 3 THOU MORE THAN STANDARD. ON REALLY HIGH LIFT CAMSHAFTS AN EXTRA 2 THOU AGAIN MIGHT BE BENEFICIAL.
Ensure that posts, spacers and rockers are evenly distributed along the length of the shaft to allow smooth pivoting.
On no account must the valve springs be allowed to become coil-bound as this will place undue stress on the rocker and could lead to failure.
At least 0.100" should be present between full valve lift and spring crush, or 0.030" between each coil of spring at full valve lift. The advantages of this assembly are similar to fitting a higher lift camshaft, but without the ordeal of stripping the engine. Only the knowledge of adjusting tappets is required. The valve actually opens and closes at exactly the same point, but the valve is open by about 20% more at any point on the camshaft lift curve which promotes airflow, accentuated when used on a high cylinder head.
WARNING This Hi-Lift rocker assembly does not appear to work well with the old meteor range of cams from Kent Cams or the Magnum range from Pipers, which are both special types of cams. They are however, designed to work with the Megadyne Kent cam range.
CHECK The adjustable nut is AF spanner size as opposed to the standard Mini size of 7/16 AF on pressed rockers. The 1300cc range and S forged rockers are AF.
PART NUMBERS Adjusting screw - AEG167. Nut - NT605061.