M110 engine
1. Using a soft metal drift, press the rear shaft bearing flush into the cylinder block. Make sure that the groove is in its highest position.
2. Install the front bearing on the intermediate shaft, then, after lubricating the rear bearing, insert both bearings into the cylinder block. Make sure the key is in the groove of the shaft.
3. Place the retaining washer together with the bolt and snap ring and tighten the bolt.
4. Install the intermediate sprocket on the shaft and remove the shaft with the bolt. Make sure the chain engages the sprocket teeth.
5. Insert the oil passage bolt and washer, tighten them to the specified torque, blocking the intermediate gear.
6. Insert the chain stop bolt into the cylinder block and tighten it.
7. Connect the driver to the intermediate gear, then install the distributor housing with a new gasket and align the groove of the drive gear with the driver. Insert and tighten the bolts.
8. If provided by the design, insert the lubrication system pressure reducing valve into the TDC sensor bracket. Lubricate the threads of the plug with sealing paste, insert and tighten the plug.
9. Install vibration damper and pulley, insert and tighten bolts.
10. Using a bolt, engage the oil pump drive shaft with the pump.
11. Lightly lubricate the plug with sealing paste and press it into the cylinder block above the oil pump drive shaft.
M123 engine
1. Lubricate the countershaft front bearing and place it on the countershaft, then insert them into the block, guiding the undercut of the bearing towards the bolt hole. Make sure that the key is in the groove of the shaft.
2. Put on the fixing washer and tighten the bolt.
3. Install the idler gear on the shaft and remove the shaft with the removable bolt. Make sure the chain is engaged with the sprocket teeth.
4. Insert and tighten the bolt, blocking the intermediate sprocket.
5. Insert the timing chain stop bolt into the cylinder block and tighten.
6. Insert the right chain guide and center the pin hole. Apply some sealing paste to the pin flange and press it into the cylinder block with a hammer.
7. Install vibration damper and pulley, insert and tighten bolts.
8. Enter the camshaft sprocket into engagement with the chain and put it on the camshaft. Insert and tighten the bolt, blocking the sprocket with a metal rod passed through one of its holes.
9. Put the cover on the front of the cylinder block with a new gasket, insert the bolts and tighten them evenly.
10. Where required by design, install the rear height control hydraulic pump.
11. After making sure that the piston of the 1st cylinder is still at TDC, insert the ignition distributor shaft into place so that its groove is approximately parallel with the cylinder block and the wide segment is directed towards the engine. After installing the chain tensioner, this parallelism must be checked again.
12. Install the guide housing and distributor spacer, then insert and tighten the bolt.
For all models
If the engine is installed on a vehicle, carry out all preliminary operations in reverse order.