The upper engine components cover the rocker cover, rocker shaft assembly, pushrods, and cam followers (tappets), the parts above the cylinder head and the most accessible area of the engine for routine maintenance such as valve clearance adjustment. The 948cc, 1098cc, 1275cc, and 1500cc each have their own components, and the parts must be matched to the correct engine variant.
1275cc Rocker Cover
The original 1275cc pressed steel rocker cover is no longer available as a new part, and the standard replacement is now an alloy rocker cover, which provides both a functional replacement and an aesthetic upgrade. The cover seals to the head via a cork gasket and is held by two studs with spacers and cup washers. Rocker cover bushes and the cap fitted to the cover are available individually.
1275cc Pushrods and Cam Followers
The 1275cc uses eight pushrods and eight cam followers (tappets), interchangeable across the entire 1275cc range regardless of engine prefix. Cam followers should be inspected for pitting or concavity on their contact face whenever they are accessible, a pitted follower will rapidly destroy a new camshaft, so renewing the followers as a set whenever the camshaft is changed is strongly recommended.
1275cc Rocker Gear
The rocker shaft assembly varies across 1275cc production, with three rocker arm types (forged, pressed, and sintered) each requiring matched adjusting screws and locknuts as detailed in the cylinder head section. The rocker assembly bolts to the head via four pillars.
1275cc Engine Nameplates
Replacement engine nameplates are available for those restoring to period-correct specification, as many original plates have been lost or damaged over the decades: MG, Austin, Weslake, and British Leyland variants are stocked.
1500 Rocker Cover
The 1500 rocker cover changed during production. Early cars used a cover with conventional studs and a cork gasket. From later production, a different cover with O-ring sealing and revised mounting studs was adopted. The two cover types and their fixings are not interchangeable.
An alloy alternative is available as both a replacement and a visual upgrade, when fitting an aftermarket cover, a blanking screw is required to seal the vent hole in the oil filler cap and maintain the closed-circuit breather system.
1500 Pushrods and Cam Followers
The 1500 uses its own pushrods and cam followers, neither of which are shared with the A-Series. The rocker arms are individually handed, numbered 1 through 8 from the water pump end, with odd-numbered arms on one side and even-numbered on the other. The rocker shaft is supported by four pillars, each with a different function and position, they are not interchangeable, and the locating pillar (which ensures correct oil feed to the rocker assembly) must be identified during reassembly.
948cc and 1098cc Tappet Covers
The earlier small-bore A-Series engines (948cc and 1098cc) used a distinctive tappet cover arrangement on the side of the block that is not found on the 1275cc or 1500. Sourcing parts for the 948/1098 upper engine is more limited than for the later engines, as production volumes for the original Midgets were lower and parts demand is correspondingly smaller. Specific items including tappet covers, gaskets, and the earlier pushrod and follower designs should be confirmed for availability before commencing rebuild work.