Land Rover Defender 2.5L 11J/12J Engine (Diesel) (1984–1993)

Land Rover’s radically updated product line was launched in 1983. Initially only the long-wheelbase One Ten was available and it was sold with the same engine line-up as the preceding Series III model- 2.25-litre petrol and diesel engines and the 3.5-litre Rover V8. However, Land Rover planned a series of rolling improvements. Launched shortly before the short-wheelbase Ninety model in 1984 was a 2.5-litre diesel engine. This was little more than an updated version of the existing diesel unit (at this time 22 years old). The stroke was lengthened to improve torque, and an updated cylinder head was used to reduce noise and emissions. A more modern injector pump improved fuel economy and an improved glow plug system improved cold-starting performance. The most significant change was the swapping of the chain-driven camshaft for one driven by a fibre toothed belt, which also drove the repositioned injector pump. The drive vacated by the injector pump was used to power a vacuum pump for the brake servo system. To reduce engine weight, extensive use of aluminium castings was made for the cambelt case, vacuum pump, rocker cover and other parts. Other small improvements were made such as the fitment of a spin-on cartridge oil filter instead of older, harder-to-change element type and the fitting of under-piston oil jets. In the mid-1980s Land Rover was part of the Land Rover Group, responsible for production of the Freight Rover van. The 2.5-litre diesel was fitted to the Freight Rover 300-series and the FX4 taxi (the engines for these applications had slight design changes, such as higher-mounted injector pumps and non-waterproof cambelt cases. They received the designations 14J and 15J respectively. Being fitted with a timing belt rather than a chain the 15J engine suffered none of the reliability problems in the FX4 that its 10J predecessor had encountered (see above)). The engine became a special-order only option after the introduction of turbodiesel engines (see below) but remained in production (and popular with military and some commercial buyers) until 1994. The British Army used this engine in the vast majority of the 20,000 Land Rovers it bought between 1985 and 1994. A manufacturing flaw with pistons combined with Army maintenance practises (such as a tendency to over-fill the sump with oil) caused the engines to over-breathe and ingest their oil, leading to piston failure. Late military-spec engines had a centrifugal separator in the breather system, allowing excess oil to drain back to the sump. These engines were designated 13J.and 11J (ref Land Rover Defender Military 110 1991 Supplementary Parts Catalogue). These later, modified engines were the first in their class (small capacity high-speed diesels) to pass the Ministry of Defence’s arduous 500-hour durability trial.

Land Rover Defender 2.5L 11J/12J Engine (Diesel) (1984–1993)

Land Rover Defender 2.5L 11J/12J Engine (Diesel) (1984–1993)

  • Layout: 4-cylinder, in-line
  • Block/head: Cast iron/cast iron
  • Valves: OHV, belt-driven camshaft, push-rod operated
  • Capacity: 2,495 cc (152.3 cu in)
  • Bore × stroke: 90.47 mm × 97 mm (3.562 in × 3.819 in)
  • Compression ratio: 21:1
  • Fuel injection: Lucas-CAV DPS rotary pump and CAV Pintaux injectors
  • Power: 68 hp (51 kW) @ 4,200 rpm
  • Torque: 114 lbf·ft (155 N·m) @ 1,800 rpm
  • Production: 1984–1994
  • Used in: Land Rover Ninety/One Ten/127, and Defender