Rover K engine

From Free net encyclopedia

The Rover Group K-Series engine is a series of engines built by MG Rover's MG Powertrain division. The engine was built in two forms; a straight-4 cylinder , available with SOHC and DOHC, ranging from 1.1 L to 1.8 L, and a V6 variation.

The K Series was introduced in 1988 as a powerplant for the Rover Metro car. It was revolutionary in that it was the first volume production implementation of the low pressure sand casting technique. This works by injecting liquid aluminium into an upturned sand mould from below. In this way any oxide film always remains on the surface of the casting and is not stirred into the casting structure. This production technology overcame many of the inherent problems of casting aluminium components, and consequently permitted lower casting wall thicknesses and higher strength to weight ratios.

The engine was introduced in 1.1 L single overhead cam, and 1.4 L dual overhead cam versions. The engines were unique in being held together as a sandwich of components by long through-bolts which held the engine under compression.

These two types of head that were bolted to the common block were designated K8 ( 8 Valves ) And K16 ( 16 Valves ). A later head design also incorporated a Rover designed "VVC" Unit (derived from an expired AP patent) which added Variable Valve Control to the platform. This allowed more BHP to be created but made the car more refined at low engine speeds. The VVC system constantly alters the cam period, resulting in a remarkably flexible drive - the torque curve of a VVC K-series engine is virtually flat throughout the rev range and power climbs steadily with no fall-off whatsoever until the rev limiter kicks in at 7,200 rpm.

The 1.8 litre versions are often used in kit cars and are starting to be used in hot rods, especially as a popular swap into the MG Midget and the Caterham versions of the Lotus 7.

By comparison, the V6 engines are more conventional engines that do not make use of the through bolts to hold the head to the block.

1 K-Series problems
2 1100
3 1400
4 1600
5 1800

[edit]

K-Series problems

The engine's head-gasket was made out of an innovative silicone-type substance rather than the more traditional materials. However the cylinder head waterways were poorly machined and the thermostat thermostat was placed in a less than optimum position. These factors often resulted in head-gasket failure, particularly in larger vehicles such as the Land Rover Freelander.

In these applications the greater body weight caused the engine to heat-up too quickly compared to the rest of the system. The thermostat would then open and a sudden rush of cooler water would enter the head causing temperature distortion.

This was relieved to a certain extent by a special pressure release thermostat which, with the aid of a spring loaded valve, allowed a small amount of cool water to enter the head so that the engine warmed-up a little slower and more evenly. However the optimum solution of moving the thermostat to the outflow from the head, allowing that rest of the water system to warm-up with the engine, was never implemented.

[edit]