318is

The M44 engine was introduced at the beginning of 1996. Based on the M42 engine, the M44's larger displacement is the result of boring and stroking the cylinder dimensions of the M42. Although peak power remains unchanged from the M42, the M44 boasts an improvement of 5 Nm of peak torque at an engine speed 200 rpm lower than its predecessor.

Changes from M42 to M44 are as follows:

1. The crankshaft is now a spheroidal-cast type with four counterweights instead of a forged steel type with eight
counterweights;
2. Connecting rods and pistons were redesigned for improved NVH;
3. Conical valve springs were used in place of cylindrical valve springs;
4. The upper valve plate has been reduced in size;
5. Balance weights in the camshafts were now cast with the camshafts themselves;
6. The timing chain tensioner was redesigned to reduce wear;
7. The DME engine management system changed from M1.7 to M5.2;
8. Induction roar has been reduced by adoption of a sound-insulating cross-flow hose in the intake system as well as an intake silencer;
9. Rocker arms now have roller bearings;
10. A hot film mass air flow sensor is used in place of a vane type sensor; and,
11. The variable length intake system switches over 600 rpm earlier.

The new engine is said to be quieter and more fuel efficient as well as offering significantly enhanced torque. BMW claim a 70% reduction in friction over the M42.

Construction time: 1995 - 2000
Capacity: 1,895 cc
Motor type: Four-cylinder in-line engine
Description: 1995 sees the displacement capacity of the 16-valve engine boosted to 1.9 litres as well. The cylinder head design has been modified. The former bucket tappets are dispensed with along with the bearing rails. The valves are now operated via roller-type rocker arms. The very small diameters of the rollers mean that the choice of valve timings results in flanks on the cams, which can now be produced using the available belt grinding process. These and a number of other measures serve to reduce friction and thus improve fuel efficiency. The arrangement of the cam followers allows for hydraulic clearance compensation in the stationary part of the valve drive.

The camshafts help to balance the additional unbalance masses, which enhances the smooth running of the engine. In principle, this special measure corresponds to the counterweights on the crankshaft.

The engine was built solely on Assembly Line 2 at Steyr, 199,425 units
Successor to the M42.