MED 1.5 LDX ROCKERS
In search of the very highest quality and performance, the MED 1.5:1 LDX roller-tip rockers are the result of over a decade of testing and development work on high-end competition engines.
Bridge-section rocker arms, an extra large diameter rocker shaft and 'W' section rocker posts all help to increase torsional rigidity and maintain valve train geometry.
We continue to develop and improve our rocker assemblies to always keep you one step ahead of the competition. Please see the additional information tab for more technical details.
- Greater contact area between the rocker shaft and the rocker arm with 17mm diameter shaft.
- Full captive rocker post design to encapsulate each rocker arm between a pair of rocker posts and reduce flex.
- Rocker arms are CNC machined from aerospace 7075 aluminium, which retains the same tensile strength as steel.
- Bridge-section rocker arms reduce flex at high rpm.
- The rocker arms are wider in the front section to give greater roller pin support.
- Roller pins have three locations to achieve maximum rigidity
- The rollers are cylindrically ground to achieve precise valve lift across the head.
- Offset option for full-race heads with offset exhaust valves.
Please note - the arm spacing of our rocker assemblies makes them suitable for 1275, 970(S) and 1071(S) based engines only. They will not suit small-bore (850, 998,1098 etc) cylinder heads.
You may also require a set of rocker post shims to perfect valve lift and centralise the rockers over the valves when the head/block faces have been machined.
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 1.5 rockers will give 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.
The MED LDX roller-tip rockers are primary aimed towards competition usage with the 1275 A-Series cylinder head, but will also suit the 1071 and 970 Cooper S engines, which share the same valve stem spacing.
If you are running a more exotic race head with offset exhaust valves, we also make an alternative design with the correctly offset arms to suit.
Although aimed at competition engines, the LDX rockers can also be used on more mild road-going engines if you're keen on having the very best rocker assembly possible. Apart from the extra cost, there are no downsides to using these on the road.
1.3:1 vs 1.5:1 rockers vs LDX
All MED race camshafts are optimised to work best with 1.5:1 rockers. If you're already satisfied with the performance of your engine, the regular 1.3 ratio will retain much of the same powerband, but with the performance and reliability of our roller-tip rocker assemblies. For those in search of a bit more power, ultimately 1.5 rockers will achieve this.
The LDX design goes one step further to reduce flex at high RPM levels, making it the ultimate choice for competition usage.
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.