MED 998 ROLLER ROCKER SET

Benefits of the MED roller-tip rockers

Standard rockers rarely give consistent valve lift across the head, even when new. After many years of use and wear, lift is likely to be even more inconsistent, so while 1.28:1 is generally given as the standard rocker ratio, a quick check of the valve lift will usually show otherwise. Optimising every aspect of the engine will enhance performance, and the 1.3 rockers should give marginally more lift than standard.

Roller tips reduce side loading of the valve stems, in turn reducing friction whilst also improving valve and guide longevity.

Add to this extra stiffness across the shaft, trouble-free tappet adjustment from enlarged adjusters, and you have an excellent performance upgrade. 

1.3:1 vs 1.5:1 rockers

All MED fast road and race camshafts are optimised to work best with 1.5:1 rockers, however we always prefer to run 1.3:1 rockers on smaller capacity engines such as 998 or 1098. These engines all seem to respond best with 1.3 rockers.

Optional extras

We always recommend changing the head gasket when removing the rocker assembly, as you may end up disturbing the gasket while loosening off the rear stud nuts. Arm clearance can sometimes be an issue when using the standard head studs and nuts, so an upgrade to ARP head studs and nuts is a good plan.

The standard steel rocker cover will clear these rockers, but aftermarket aluminium types will usually catch the arms on the rear corners. So either machine out material from the inside of the cover or upgrade to an MED rocker cover, which comes pre-machined internally to suit.