To replace the camshaft timing chain on a vehicle-mounted engine, you must have a hand grinder handy. New camshaft drive chains are always supplied with removable locking links provided for their installation. Replacing the camshaft chain must be carried out as follows:
- remove all parts that prevent access to the camshaft drive chain;
- remove oil spray nozzles (although this will require additional work, but the engine will be easier to crank);
- remove the cylinder head cover;
- remove chain tensioner (subsection 2.12.1);
- cover the chain case with a piece of rag;
- grind off the riveted heads of the chain link fingers with a grinder. Do not disconnect the chain yet;
- attach the new camshaft drive chain to the old chain by pulling the worn link out of the old chain;
- using a wrench with a replaceable socket head and a ratchet inserted into the crankshaft belt pulley mounting bolt, slowly turn the crankshaft in the working direction of its rotation;
- during the slow rotation of the crankshaft, it is necessary to keep the old drive chain in a taut position by the free end, while its other end, connected to the new chain, will lead the latter to the sprockets. Ensure that the chain does not disengage from the camshaft drive sprocket and crankshaft sprocket;
Pic. 98. Installing the connecting link-lock in the drive chain (this operation must be carried out from the side indicated by the arrow)
- as soon as both ends of the new chain are at the top of the camshaft drive sprocket, the old chain is disconnected from the new one, and a removable locking link is inserted into the free holes of the rollers of the new chain from the inside out, as shown in fig. 98. Install new circlips on chain link pins. In this case, both ends of the chain should be temporarily tied with wire to the camshaft drive sprocket so that they do not fly off it into the chain housing;
Pic. 33. Location of the camshaft guide pin (up). The location of the alignment marks corresponding to the position of the piston of the first cylinder at TDC (at the bottom): 1 - mark on the camshaft sprocket; 2 - mark on the cover of the first camshaft bearing
- rotate the crankshaft until the piston of the first cylinder stops at TDC. Then check (on the crankshaft pulley or on the vibration damper), so that in this position of the crankshaft pulley, the camshaft marks take the position shown in fig. 33. If this did not happen, then it is necessary to check the camshaft drive mechanism and the fuel pump, as described in the relevant subsections;
- the remaining work is performed in the reverse order of removal.
Note. It should be remembered that drive chains can also be connected using conventional plug-in links. In this case, the outer plate of the chain must be well pressed against the rollers, and the protruding ends of the link fingers must be riveted. This work must be done at the service station. The above description applies to chains with removable locking links.