Toyota MZ Engine
The Toyota MZ engine family is a V6 piston engine series. The MZ series has an aluminium engine block and aluminium alloy DOHC cylinder heads. The cylinders are lined with cast iron, and is of a closed deck design (no open space between the bores). The engine is a 60 degree V6 design. It uses multiport fuel injection (MFI), four valves per cylinder, a one-piece cast camshaft and a cast aluminium intake manifold. The MZ family is a lightweight V6 engine of an all-aluminium design, using lighter weight parts than the heavier duty VZ block engines in an effort to lower production costs, decrease engine weight, and decrease reciprocating weight without sacrificing reliability. Toyota sought to enhance the drivability pattern of the engine (over the 3VZ) at exactly 3000 rpm, since that was the typical engine speed for motors cruising on the highway. The result was less cylinder distortion coupled with the decreased weight of rotating assemblies, smoother operation at that engine speed, and increased engine efficiency.
They feature cast aluminium pistons with an anti-friction resin coating (moly) and valve depressions that decrease the chance of valve-to-piston interference in case of timing belt failure on motors without VVT-i. They also use steel rings, smaller-diameter shot-peened rods, and a forged steel crankshaft.
This engine has been phased out in most markets, replaced by variants of the new GR series.