Timing chain idler pulley, replace.

# Timing chain idler pulley, replace. S14

Remove nuts holding spark plug harness to valve cover, remove spark plug boots and place harness aside. |
Remove the eighteen 10mm nuts securing valve cover. |
Remove valve cover. |
Remove the two 8mm Allen bolts from upper chain guide and remove guide. |
Place engine on Top Dead Center. Crank pulley has an O|T mark. The line is TDC. Cams have groves that should line up to the groves on the forward cam journals. |  |
Remove timing chain tensioner plug. Plug is 19mm, main housing is 32mm. Either can be removed. |
CAUTION: Timing chain tensioner is under spring pressure, keep inward force on it while unscrewing it. A small amount of oil will drain out when plug is removed.
Remove the two 10mm nuts and cover from in front of intake cam. |
Bend locking tab back from each of the six cam gear nuts, remove nuts and locking plate. |
Pull intake gear off camshaft, hold chain in position and lower gear while moving towards exhaust cam to disengage from chain. Lift gear out past chain |
Warning : Do not rotate crank or camshafts while chain is off. |
Remove the 10mm nut and washer locking the idler shaft into cylinder head. |
Thread an appropriate sized slide hammer tool into the end of the idler shaft and pull shaft from head. Alternately, thread a 10x1.5 bolt into the end of the idler shaft and pull while rotating to remove. Take care to not allow the idler pulley to fall into engine. |
Lift idler pulley out of cylinder head.
If replacing bearing only, drive old bearing out of gear and press new one in.

### Installation

Replace and lubricate idler shaft O ring with engine oil. |
Ensure that there is no slack in timing chain on left side of engine. |
Rotating exhaust cam slightly toward intake cam will allow intake cam gear to be installed easier. |
CAUTION: Rotate exhaust cam back into position before tightening bolts on intake cam gear.
Replace locking plate for cam gear bolts.
Replace and lubricate O ring on cam gear access cover with engine oil. |
Replace crush rings on timing chain tensioner.
Using a 30mm socket on the crank pulley, rotate engine at least two full revolutions, ending with the engine at TDC. Check all timing marks.
CAUTION: Failure to double check cam timing could result in severe engine damage.

### Torques :

Valve cover nuts | : | 9 ± 1 Nm (6.5 ± 0.5 ft lbs.)

### Part numbers :

Valve cover gasket - outer | : | 11 12 1 312 171
Valve cover gasket - inner (2 required) | : | 11 12 1 312 173

E30 M3 Repair Manual V2.7. Copyright ©1999-2001 Koala Motorsport & Brett Anderson