Details of the distribution chain on the engine M 123
28 - crankshaft sprocket; 53 - camshaft gear; 85 - right guide; 89 - top guide; 93 - bottom guide; 94 - restrictive pin; 98 - intermediate gear; a - tensioner
Details of the distribution chain on the engine M 110
1 - gear of the exhaust camshaft; 2 - top guide; 2a - intermediate gear; 2b - bottom guide; 3 - intake camshaft gear; 4 - guide wheel; 5 - restrictive pin; 6 - intermediate gear; 7 - distribution chain; 8 - crankshaft sprocket; 9 - rolling axis; 10 - right guide; 11 - hydraulic chain tensioner
Removing the timing chain link
1. Remove spark plugs and valve cover (right side of the engine M 110).
2. If necessary, the cam followers can be removed to make turning the engine easier.
3. Rotate the engine two full turns and check that the chain has a connecting link. If there is no such link, put a rag on the cam drive sprocket and grind the ends of the axis of one single link.
4. Remove the chain tensioner.
5. Slide the removable link onto the cam drive sprocket, remove the link and attach the new camshaft chain with the new link. Keep the chain engaged with the sprocket and have a helper crank the engine while the new chain is seated on the sprockets.
6. With the free ends of the chain on the sprocket, insert the link from the rear and replace the washers and cleats. If there is only one clamp, its closed end must face in the direction of rotation.
7. Install the chain tensioner.
8. Install the cam followers and check the timing.
9. Install valve cover and spark plugs.