Contents: Camshaft Sprocket ↡ Crankshaft sprocket ↡
Camshaft Sprocket
Removal
1. Remove the upper drive chain cover.
2. Set the piston of the first cylinder to top dead center and check that all timing marks are aligned with the pointers.
3. Remove the drive chain tensioner mechanism.
4. Using paint, apply alignment marks to the camshaft sprocket and timing chain link, and the camshaft sprocket and camshaft.
5. Remove the three bolts, remove the sprocket from the camshaft and remove it from the drive chain. Always keep the drive chain taut to prevent the drive chain from coming off the crankshaft sprocket.
6. Remove the woodruff key from the camshaft groove.
Examination
1. Check the condition of the teeth on the sprocket. The teeth on the sprocket are symmetrical and if the teeth on one side are worn out, the sprocket must be replaced.
Installation
Attention! The camshaft sprocket has several modifications, so when replacing the sprocket, you must consult with Mercedes-Benz representatives.
1. Install the woodruff key into the groove on the camshaft
2. Check that all timing marks are aligned with the pointers. When installing a new camshaft sprocket, apply alignment marks to it in the same locations as on the old sprocket.
3. Place the chain on the sprocket, aligning the previously applied marks.
4. Install the sprocket on the camshaft in accordance with the previously applied marks and secure it with bolts.
5. Install the drive chain tensioner mechanism.
6. Turn the engine crankshaft 2 full turns clockwise and check that all timing marks are aligned with the pointers.
7. Install the upper drive chain cover.
Crankshaft sprocket
Removal
Caution! When removing the crankshaft sprocket, it is necessary to cut one link of the oil pump drive chain. Therefore, either prepare a new chain link or a new oil pump chain. To remove the crankshaft sprocket, it is necessary to use a puller.
Attention! When removing the chain, it is necessary to use an emery wheel or vulcanite to cut off the protruding caps of one of the chain links.
Remove the shoe (1) of the oil pump drive chain tensioner mechanism, the bushing (2) and the spring (3) from the pivot pin
1. Remove the drive chain tensioner shoe.
2. Cover the oil pan with a clean rag.
3. Remove the oil pump drive chain tensioner shoe from the pivot pin. Remove the bushing and spring from the pivot pin. Mark the location of the spring for proper reinstallation (see picture).
4. Using an emery stone or vulcanite, grind down the frayed ends of the oil pump drive chain link on the top of the crankshaft sprocket.
5. While supporting the chain, remove the retaining plate and knock the chain connecting link out of the chain.
6. Being careful not to allow any chips to fall into the oil pan, remove the rag covering the oil pan.
7. Using soft wire, tie the ends of the oil pump drive chain to prevent it from coming off the oil pump sprocket.
8. Place alignment marks on the drive chain and camshaft sprocket, then remove the drive chain from the sprocket.
9. Remove the drive chain from the crankshaft sprocket. Note the orientation of the sprocket and use a puller to remove the crankshaft sprocket.
10. Remove the woodruff key from the crankshaft keyway.
Examination
1. Check the condition of the teeth on the sprocket. The teeth on the sprocket are symmetrical and if the teeth on one side are worn out, the sprocket must be replaced.
Installation
1. Install the woodruff key into the crankshaft keyway.
2. When installing a new sprocket, transfer the marks from the old sprocket to the same locations on the new sprocket.
3. Heat the crankshaft sprocket to 50°C, align the sprocket groove with the woodruff key and install the sprocket on the crankshaft.
4. Install the drive chain onto the camshaft sprocket according to the previously applied marks.
5. Install the drive chain onto the crankshaft sprocket, aligning the marks on the sprocket and chain.
6. Position the ends of the oil pump drive chain on the crankshaft sprocket, then connect the ends of the chain with a connecting link. Install the locking plate on the connecting link and rivet the connecting link. Check that there are no metal burrs left after riveting.
7. Install the bushing, spring and tensioner shoe onto the pivot pin.
8. Install the drive chain tensioner shoe.