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The K-Series engine is a series of engines built by Powertrain Ltd, a sister company of MG Rover. The engine was built in two forms: a straight-four cylinder, available with SOHC and DOHC, ranging from 1.1 litres to 1.8 litres, and a V6 version, known as the KV6.
The K-Series was introduced in 1988 by Rover Group as a powerplant for the Rover 200 car. It was the second volume-production implementation of the low-pressure sand-casting (or LPS) technique in a new plant sited between East Works and Cofton Hackett. (The first volume application of the LPS process had been for the M-16 cylinder head, produced in South Works, adjacent to the former forge). The LPS process pumped liquid aluminium into a chemically-bonded sand mould from below. This reduced oxide inclusions and gave a casting yield of around 90%, compared with 60% for more conventional gravity casting processes. The process avoided many of the inherent problems of casting aluminium components and consequently permitted lower casting wall thickness and higher strength-to-weight ratios. However, the process required the use of heat-treated LM25 material which gave the engines a reputation for being fragile. An engine overheat would often result in the material becoming annealed and rendering the components scrap. The aluminium engine blocks were fitted with spun-cast iron cylinder liners that were initially manufactured by GKN's Sheepbridge Stokes of Chesterfield, but these were replaced by liners made by Goetze after some seminal research conducted by Charles Bernstein at Longbridge, which proved influential even to Ducati for their race engines. Unfortunately a large number of aftermarket engines, the so-called "VHPD"s", were built with the old substandard GKNs by Minister, Lotus and PTP well after the Goetze liner's introduction to the production line in 2000.
The engine was introduced initially in 1.1 litre single overhead cam and 1.4 litre dual overhead cam versions. Because Honda stopped providing Rover with engines after the end of their relationship, but well before the BMW takeover, an enlargement of the K Series design to 1.6 and 1.8 litres was carried out. This was done by using larger diameter cylinder liners and also increasing the stroke. The change required a block redesign with the removal of the cylinder block's top deck and a change from "wet" liners to "damp" liners. The plastic throttle body fitted to the engine until 2001 was manufactured by the SU Carburettor company. They also included aluminium and larger sized bodies.
The four-cylinder engines were held together as a sandwich of components by long through-bolts which held the engine under compression, though this construction is not unknown in early lightweight fighter engines from the First World War. It had also been used in motorcycle engines and Triumph Car's "Sabrina" race engine. The V6 engines are more conventional engines that do not make use of the through bolts to hold the head to the block.
The two types of head that were bolted to the common four-cylinder block were designated K8 (8 valves) and K16 (16 valves). A later head design also incorporated a Rover-designed Variable Valve Control (VVC) unit (derived from an expired AP patent). This allowed more power to be developed without compromising low-speed torque and flexibility. The VVC system constantly alters the inlet 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.
Following the collapse of MG Rover in 2005, the Chinese automaker Nanjing Automobile acquired the Longbridge plant and the intellectual property rights to many designs, including those of the K series engine. The Chinese owner, now SAIC Motor, went on to further develop the K series engine, renaming it "N series" and using it to power its current range of MG cars, the MG 6. The revisions included a different design of cylinder head gasket, higher tensile strength through-bolts and a stronger oil-rail fitted in the bottom end of the engine that the through bolts screw into. These revisions are sold by the British company XPart to solve the issues that some K series engines had of cylinder head gasket failure.
Early K8 engines used a single SU KIF carburetter with a manual choke and a breaker-less distributor mounted on the end of the camshaft. MEMS Single point injection became standard with the launch of the Rover 100 in 1994.
K16 models used MEMS, with a 1.6 ECU from 1990 until 1994 and a 1.9 ECU from 1995 onwards, in either Single Point or Multi Point forms, with a single coil on the back of the engine block and a distributor cap and rotor arm on the end of the inlet camshaft. MEMS 2J was used on the VVC engine, to control the Variable Valve Control and the distributorless ignition system, which was used because there were camshaft drive belts at both ends of the engine. With the launch of the Rover 25 and Rover 45 in 1999, MEMS 3 was introduced, with twin coils and sequential injection.
Early KV6 as used in the Rover 800 used MEMS 2J, which controlled the three wasted spark coil packs and variable intake manifold geometry. The later KV6 used Siemens EMS 2000.
All 1100 engines displace 1.1 L (1,120 cc/68 cu in). Four variations were created:
Cars that came with the 1100:
Engine Codes: 14K2F (8V), 14K4F (16V), 14K16 (16V)?
All 1400 engines displace 1.4 L (1,396 cc/85 cu in). Six variations were created:
The K16 82 hp variant is exactly the same as the 103 hp (77 kW) version, apart from a restrictive throttle body designed to lower the car's insurance group; the 90 hp (67 kW) Spi features single-point fuel injection rather than the multi-point of the later engine.
Cars that came with the 1400:
Engine Code: 16K4F
All 1600 engines displace 1.6 L (1,588 cc/96 cu in) and have DOHC, 16 valves and MPI. Two variations were created:
Cars that came with the 1600:
Engine Codes: 18K4F, 18K4K (VVC variants)
All 1800 engines displace 1.8 L (1,796 cc/109 cu in) and have DOHC, 16 valves and MPI. Six versions were created:
Cars that came with the 1800: