MED 1.3 ROCKER SET

The assembly is a direct replacement on 1275 engines, but no, the shaft itself is a larger diameter for increased strength. We have also enlarged the rocker arm adjusters for heavy duty performance usage and reliability. All round, these are much stronger than standard rocker assemblies.

As with most A-Series engine upgrades, it depends! All MED fast road and race camshafts are optimised to work best with 1.5:1 rockers, and the extra valve lift will result in increased power output for most applications. However, if you'd like all of the advantages of our roller rocker assemblies without the extra valve lift, 1.3 rockers remain popular. Perhaps you're restricted to a maximum valve lift figure in your race regulations, you have an SPi/MPi Mini and wish to keep emissions in check, or simply prefer to run less lift - we have rockers to suit.

MED rockers are all roller-tip rather than full roller rockers, as we have found this gives the best longevity and accuracy. We run the 7075 aluminium rocker arms direct on the shaft, taking advantage of its larger diameter to spread the load. This is preferable to running needle roller bearings within the arms, from our experience.

Not all A-Series roller rocker assemblies are created equal, and we have gone to great lengths to ensure these are the most durable setup possible, whether it's for a long-distance road trip Mini or full-race car. Take the roller tips as an example, which feature a unique three-way retention technique at the roller pins. The 7075 aluminium arms have a higher tensile strength than many grades of steel, while the enlarged adjuster screw threads are there for ultimate longevity.

The MED roller-tip rockers are designed for 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 have a small-bore engine, we make a set specifically to suit, unless of course you are running a 1275 head on a small-bore block - then these will fit no problems. If you are running a more exotic race head with offset exhaust valves, you will need to upgrade to the LDX rockers, which are available in a special offset design.

Be wary of clearance between the rocker arms and the spacers, and also the rocker post stud nuts and the arms. We assemble the rocker shaft spacers to try and give the correct end float for most cylinder heads, but you can find variety here in the castings. If the arms are too tight against the spacers, firstly loosen the stud nuts and there will be some lateral movement of the posts, which often fixes it. In rare cases you may need to turn down the spacers a small amount to give more clearance (suggest around 0.005-0.010"). Check that the rocker post stud nuts/washers do not overhang the posts and contact the arms. If so, consider using an ARP head set, or machine down the fixings for clearance.

Yes these should fit inside a standard steel/tin rocker cover. For thicker-walled aluminium rocker covers, you will need to machine the inside rear edges for clearance, or perhaps take a look at the MED rocker covers, which come machined internally.

Yes it might be a good idea to order a set or two to experiment with. When the cylinder head or block have been machined, the valve seats re-cut, or a combination of all three, it can all affect the rocker geometry on an A-Series engine. The aim should be to achieve the correct valve lift of the camshaft at full lift, roughly indicated by the roller tips sitting centrally (fore and aft) on the valve tip at half lift. If the rocker geometry is incorrect, you will not achieve the desired 1.3:1 ratio between the cam and valve lift figures. Winding the adjusters out to their extremes may also give clearance issues with the pushrods.

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.