This engine received a direct ignition system with external camshaft and crankshaft sensors. Each cylinder had one inlet and two exhaust valves actuated by a single overhead camshaft. Each cylinder head had a single chain-driven camshaft and an individual downdraft CV carburetor. Each Cylinder has its own injection pump which is driven by its own camshaft. The pushrods activating the valves from the top camshaft were almost horizontal. This featured an overhead camshaft (OHC) and an alloy cylinder head. Valve actuation is via rocker arms and a hollow, belt-driven single overhead camshaft. The engine was also updated with a slightly revised camshaft and roller lifters. It has a single overhead camshaft driving six valves. The alternator is gear-driven off the camshaft. The 1HZ engine has a single overhead camshaft, 12 valves and produces from its capacity. It had a longer-duration camshaft, still with hydraulic lifters. Another improvement was use of a hydraulic lifter/roller camshaft on most 1987 LG4s. It has 16 valves and a DOHC (double overhead camshaft) design. It has 16 valves and a double overhead camshaft (DOHC) design.