Checking and installing TDC of the first cylinder of the engine in the compression stroke is needed when carrying out work to remove the camshaft drive chain
It should be borne in mind that when installing according to marks on the crankshaft pulley and the oil pump housing, the piston of both the first cylinder and the piston of the fourth cylinder can be in this position
There are no marks on the camshaft sprocket. There is only a groove at the front end of the camshaft, which indicates that the camshaft is also at TDC.
In order to determine in which of the cylinders the compression stroke, you need to remove the cylinder head cover, check the ease of movement of the rocker arms of the valves of the first and fourth cylinders, or remove the master disk of the phase sensor in order to determine by the position of the groove in the rear end of the camshaft.
After that, you need to make sure that the marks on the crankshaft pulley and the oil pump housing match.
If the labels do not match, then the valve timing is broken.
In this case, it is necessary to loosen the camshaft sprocket mounting bolt and, with the camshaft position unchanged, turn the crankshaft until the marks coincide.
We turn the engine crankshaft until the marks on the crankshaft pulley and the oil pump housing match.
We fix this position of the crankshaft by inserting a pin about 6 mm in diameter into the hole.
The crankshaft can be turned over the flywheel ring gear.
To do this, remove the plug from the hole in the flywheel housing
We rotate the flywheel by the teeth of the crown with a large screwdriver, resting it on the edge of the hole
Removing the vacuum pump
We check the position of the groove in the front end of the camshaft under the shank of the vacuum pump shaft.
The groove must be strictly vertical.
To determine in which cylinder the piston is in the TDC position of the compression stroke, remove the head cover
We try to shake our hand on the axes of the rocker arm "A" of the valve drive of the first cylinder and rocker arm "B" of the valve drive of the fourth cylinder.
In that cylinder, both rocker arms of which move freely, the piston is at TDC of the compression stroke.
To restore the correct valve timing, you need to remove the engine, since access to the valve timing drive is not possible on the car.
On the removed engine, in order to correctly set the valve timing, remove the retaining pin, which was installed from the holes of the crankshaft pulley and the oil pump housing.
We turn the crankshaft in the required direction until the groove on the front end of the camshaft is installed in the correct position.
We fix the camshaft in this position using the tool
Figure 8 shows the camshaft locking tool.
We unscrew the five bolts securing the crankcase cover of the timing drive
Remove the cover
Holding the camshaft from turning by the holes of the phase sensor driver disc, loosen the tightening bolt of the driver disc and the camshaft sprocket.
We crank the crankshaft until the holes in its pulley and the oil pump housing coincide and tighten the bolt securing the drive disc and the camshaft sprocket.
If on the removed engine it is required to determine in which TDC cylinder of the compression stroke, then this can be done without removing the head cover.
We completely unscrew the bolt of fastening of the master disk of the phase sensor
Removing the disc
After removing the disc, it becomes visible a groove at the rear end of the camshaft, which will be directed strictly downward if the piston of the first cylinder is at TDC of the compression stroke.