This is a 1988 Land Rover Defender 90 that’s been given a series of upgrades, the most significant of which is the fitment of a Mercedes OM617 turbodiesel inline-five – an engine famous for its ability to last a million kms or more with only routine maintenance.
This engine sends power back through an Ashcroft R380 5-speed manual transmission, and the whole conversion was done by Ferraris and More of Garland, Texas. This engine can run on standard diesel, red diesel, biodiesel, and JP-1 (jet fuel), meaning you should be able to find fuel for it almost anywhere.
Fast Facts: A Mercedes-Powered Land Rover Defender 90
- This is a 1988 Land Rover Defender 90 that’s been converted to run a Mercedes OM617 turbodiesel inline-five, an engine widely known for its extreme reliability. Power is routed through an Ashcroft R380 5-speed manual, giving the truck genuine highway usability, and the OM617 has broad fuel tolerance for remote or expedition use.
- The OM617 was developed by Mercedes-Benz in the 1970s as a reliable diesel for use in large luxury sedans, without excessive noise or vibration. It uses an all-iron block and head, indirect injection, a mechanical Bosch pump, and conservative mechanical design focused on longevity rather than outright power output.
- Naturally aspirated and turbocharged OM617 variants appeared across multiple Mercedes platforms, including W115, W123, W116, W126, and G-Wagen models. Turbo versions introduced in the late 1970s made the 300SD one of the first series-production turbodiesel passenger cars, loved for its torque and reliability, rather than its speed.
- This Defender conversion was completed by Ferraris and More in Texas and includes supporting upgrades covering cooling, fuel delivery, wiring, and starting systems. Output is listed at 149 bhp and 236 lb ft, with power sent through a 5-speed manual transmission and a dual-range transfer case.
History Speedrun: The Mercedes OM617 Inline-Five
Mercedes-Benz engineers developed the OM617 in the 1970s to solve a real world problem – they needed to give a large, heavy, luxury sedan acceptable performance and good mileage. And they had to do it using diesel power – without the noise and vibration penalties that made many 1970s-era passenger-car diesels feel positively agricultural.
The OM617 family started out as a 3.0 liter unit, using indirect-injection with an all-iron block and head. It used a chain-driven single overhead camshaft operating two valves per cylinder, and it was fitted with a mechanical Bosch inline injection pump. Image courtesy of Daimler-Benz AG.
What they developed was an inline-five cylinder, naturally-aspirated diesel engine that sat neatly between a four and a six for smoothness and engine bay packaging. The OM617 family started out as a 3.0 liter unit, using indirect-injection with an all-iron block and head. It used a chain-driven single overhead camshaft operating two valves per cylinder, and it was fitted with a mechanical Bosch inline injection pump.
Bore and stroke was 91 mm by 92.4 mm in early form, with later variants moving to a 90.9 mm bore to land at 2,998cc. The architecture was deliberately conservative and biased towards toughness, with thick castings, modest engine output, and an operating range that keep mean piston speeds and stresses well under control.
Naturally aspirated OM617s arrived first and were used in many of the Mercedes’ mid-size sedans and wagons of the time. Early versions appeared in the W115 240D 3.0 / 300D, and the best-known naturally aspirated applications followed in the W123 range, including the 300D, 300TD wagon, and North American-market 300CD.
Power outputs varied by market and year and while horsepower was never remarkable, they did offer decent low-speed torque, steady pull, and a willingness to basically run forever if given logbook maintenance. There are many examples used in taxis that exceeded 1,000,000 kms (620,000 miles) with nothing more than oil changes and basic upkeep.
Mercedes developed turbocharged OM617 variants in the mid-1970s and brought the concept to production in 1978 with the OM617.950 in the W116 300SD – this car is now widely cited as the first series-production turbodiesel passenger-car sedan. In factory tune, early versions were rated at 109 bhp, with this figure later increasing to 119 bhp, with torque rising from 168 lb ft to 170 lb ft depending on year.
The Mercedes G Wagon, now named the G Class, also made use of the OM617, with the 300GD model receiving a version capable of 88 bhp and 127 lb ft of torque, though exact output was market and year dependent. Although not powered by any stretch of the imagination, it was the bulletproof reliability of the engine that made it such a popular choice for military, police, search and rescue, and expedition work.
The engine conversion work was completed by Ferraris and More of Garland, Texas, the job also included the fitment of an Ashcroft R380 5-speed manual transmission, and a 120cc performance fuel injection pump an additional oil feed line, and replacement wiring.
The 300SD turbo OM617.950 version of the engine was produced from 1978 to 1980, after which Mercedes evolved the design further with the OM617.951 for the W126 300SD Turbo and the closely related OM617.952 for turbocharged North American W123 models, including the 300D Turbo, 300CD Turbo, and later 300TD Turbo wagons. Output climbed again from late 1982 to 123 bhp, with torque up to 184 lb ft.
Under the skin, production turbo engines received a series of internal revisions to handle increased heat and cylinder pressure. These upgrades included the addition of piston oil cooling jets, strengthened connecting rods, sodium filled valve stems, a stronger nitride-hardened crankshaft, and a series of durability-focused changes tied to turbo lubrication and thermal loads.
The result is the OM617 that remains common in high-mileage daily drivers, commercial conversions, and expedition builds decades later, loved for its mechanical simplicity, its rebuildability, and its dependability in the face of high mileages and varying fuel qualities.
The 1988 Land Rover Defender 90 Shown Here
The Land Rover Defender 90 you see here in this article has had its original engine removed and replaced with one of the most famously-reliable engines in production car history – the Mercedes-Benz OM617.
The engine conversion work was completed by Ferraris and More of Garland, Texas, the job also included the fitment of an Ashcroft R380 5-speed manual transmission, and a 120cc performance fuel injection pump an additional oil feed line, and replacement wiring.
The engine swap also required a gear reduction starter, electric cooling fan, Revotec fan controller, A/C compressor, valve cover gasket, radiator hoses, and engine mounts. Additional engine work included adjusting the valves, cleaning the injectors, and changing the oil and fuel filters.
The Land Rover Defender 90 you see here in this article has had its original engine removed and replaced with one of the most famously-reliable engines in production car history – the Mercedes-Benz OM617.
Power output is now listed as 149 bhp and 236 lb ft of torque, and the engine can run on standard diesel, red diesel, biodiesel, and JP-1 (jet fuel). Power is sent back through that 5-speed gearbox through a dual-range transfer case to either the rear axle only, or the front and rear axle when required.
This unusual Defender 90 is now being offered for sale out of Garland, Texas with a dyno sheet, modification and service records, a clean Carfax report, and a clean Texas title in the seller’s name. If you’d like to read more about it or register to bid you can visit the listing here.
Images courtesy of Bring a Trailer
Articles that Ben Branch has written have been covered on CNN, Popular Mechanics, Smithsonian Magazine, Road & Track Magazine, the official Pinterest blog, the official eBay Motors blog, BuzzFeed, Autoweek Magazine, Wired Magazine, Autoblog, Gear Patrol, Jalopnik, The Verge, and many more.
Silodrome was founded by Ben back in 2010, in the years since the site has grown to become a world leader in the alternative and vintage motoring sector, with well over a million monthly readers from around the world and many hundreds of thousands of followers on social media.
