Based on the N46B20, the younger version of the N46 series, known as the N46B18, was created in 2004 and manufactured exclusively for the BMW E46 316. This power unit was also not widely used, given that the E46 was discontinued in 2005.
In contrast to the base engine, the 1.8-liter crankshaft was swapped out for a short-stroke one (81 mm as opposed to 90 mm for 2.0 liters), pistons with a 10.2 compression ratio, and an intake manifold devoid of a DISA system.
This engine was designed to replace the N42B18. Unlike the 42nd, the new N46B18 engine has a different timing chain tensioner, a new intake manifold, spark plugs, a generator, the Valvetronic control unit is integrated in the ECU, and a few other minor details. Engine management system Bosch ME 9.2.
Specifications
| Production years | 2004-2005 BMW Plant Hams Hall |
| Displacement, cc | 1796 |
| Fuel system | injector |
| Power output, hp | 116 |
| Torque output, Nm | 175 |
| Cylinder block | aluminum R4 |
| Block head | aluminum 16v |
| Cylinder bore, mm | 84 |
| Piston stroke, mm | 81 |
| Compression ratio | 10.2 |
| Features | Valvetronic |
| Hydraulic lifters | yes |
| Timing drive | chain |
| Phase regulator | double VANOS |
| Turbocharging | no |
| Recommended engine oil | 5W-30 |
| Engine oil capacity, liter | 4.25 |
| Fuel type | petrol |
| Euro standards | EURO 4 |
| Fuel consumption, L/100 km (for 316i E46) — city — highway — combined |
9.9 5.5 7.1 |
| Engine lifespan, km | ~320 000 |
Disadvantages of the N46B18 engine
The motor’s excessively high operating temperature is the primary cause of its issues;
Initially, oil consumption starts when the valve stem seals quickly tan;
Additionally, the curdled grease blocks the oil channels and turns off Valvetronic; the timing chain or VANOS system will probably need maintenance even before 100,000 kilometers;
After 50 to 70 thousand kilometers, valve cover leaks typically start to show.