Mercedes-Benz OM352 engine

The Mercedes Benz OM352 Engine was a 5675 cm3 (5.7 litres, 345 cubic inch) displacement inline 6 cylinder 4 stroke Diesel engine. It was also sold as a industrial engine by Daimler Benz AG. It was also available with a turbo charger and was then designated as OM 352 A, and with a charge air cooler and was then named OM 352 LA. (List of Mercedes-Benz engines.)

The engine is watercooled, and is produced using cast iron cylinder block, with cast-in cylinders. The engine utilizes diesel fuel delivered in a direct injection method from a Bosch PES style inline injection pump. The cylinder head is a single unit for all cylinders, and the cylinder head cover are cast in light alloy metal, and the air intake is cast on.

The crankshaft is a precision forged unit running in seven three-layer bearings, with counterweights bolted on to the crank webs. The middle bearing is also the thrust bearing. The connecting rods are of a split design, with bronze bushings for the piston pin.

The engine was used in a number of different applications, such as generator sets, propulsion engine, and construction equipment. mtu sold the engine as 6R 095 AZ / TA / TC where AZ is naturally aspirated, TA is with turbo and AZ is with turbo and intercooler.

The OM 352 was also one of many Mercedes engines licenced in 1979 for manufacture by Atlantis Diesel Engines (ADE) in South Africa. These were known as ADE 352 and are virtually identical to the Mercedes engines.

Recently the OM 352 was licenced by TATA for use in their 713S Trucks. These are manufactured by TATA but however have slight differences like the weights no longer being bolted to but rather part of the crank and no holes for oil sprayers in the block.

Injection side of engine

Exhaust side of engine

Common output power can vary from 92 kW to 141 kW (126 to 192 hp) depending on the fuel delivery and air charge options.

Below is listed the specifications for a 130 hp (97 kW) OM352, model 353.961. This variant is commonly used in Mercedes Benz Unimog, such as the U1100 and U1300 models. ^[1]

Mercedes Benz Type: 352
Model: 353.961
Combustion System: Four-stroke diesel with direct injection
Number of cylinders, Cylinder arrangement: 6, vertical in-line
Bore: 97 mm
Stroke: 128 mm
Total displacement: 5657 cm²
Compression ratio: 17:1
Compression at starting speed: 22 bar up to 24 bar (2.2 to 2.4 MPa), minimum 20 bar
Continuous output at nominal speed: 96 kW (130 hp) @ 2800 rpm
Maximum torque at speed: 363 N·m (267 ft·lbf) @ 1700 rpm
Idle Speed: 700 rpm
Start of fuel delivery before TDC: 18 degrees
Injection Sequence: 1 - 5 - 3 - 6 - 2 - 4
Valve clearance, cold: (inlet 0.20 mm) (exhaust 0.30 mm)
Opening pressure of injection nozzles: 200 bar (20 MPa) + 10 (new), 180 bar minimum (used)
Operating temperature: 95 degrees Celsius
Oil pressure: nominal 2–5 bar (200–500 kPa), idle min 0.6 bar
Weight, dry: 460 kg, 1014 lb

1. ^ Information from the Unimog 435 Workshop manual, Book 1 Section 1.2/1