Place engine on cylinder 1 at 40 degrees after top dead center - AR05.10-P-7620-04MM

ENGINE 152.9, 157, 276, 278 

Shown on engine 276 

Fig 1: Belt Pulley/Vibration Damper And Coolant Pump Reference Edge

Courtesy of MERCEDES-BENZ USA

Engine 152.9, 157, 278, shown on engine 278 

Fig 2: Belt Pulley/Vibration Damper - Shown On Engine 278

Courtesy of MERCEDES-BENZ USA

Shown on engine 276 

Fig 3: Camshaft Adjuster & Laser Markings - Top Markings

Courtesy of MERCEDES-BENZ USA

Shown on engine 276 

Fig 4: Camshaft Adjuster & Laser Markings - Bottom Markings

Courtesy of MERCEDES-BENZ USA

1. Rotate engine at the center bolt of the crankshaft in direction of engine rotation until marking for a 40°  CKA on the belt pulley/vibration damper (10) coincides with reference edge (10a).

   The reference edge (10a) is located for engine 276 on the coolant pump and for engines 152.9, 157, 278 on the poly-V belt tensioning device.

   The engine must not be turned against the direction of rotation of engine otherwise the timing chain can get jammed.

2. Check position of camshafts based on the laser marks (arrows).

   If the laser marks on the camshaft adjusters (2) are located at the top (see Fig 4) and the mark 40° is at the reference edge (10a), then cylinder 1 is at 40° after ignition TDC.

   If the laser marks on the camshaft adjusters (2) are located at the bottom (see Fig 4) and the mark 40° is at the reference edge (10a), then cylinder 1 is at 40° after overlap TDC.

   A complete crankshaft revolution (360°) lies between 40° after ignition TDC and 40° after overlap TDC on cylinder 1.