Remove the bearing caps No. 5, 1 and 3 of the camshaft, then alternately unscrew the nuts of the studs securing the bearing caps No. 2 and 4 in a cross pattern.
Remove the camshaft from the cylinder head bearings and remove the valve lifters.
Install a valve spring compressor or a special VW 541 device for removing and installing valve cotters on the cylinder head and, using pliers with pointed ends, release the valves from crackers, after pressing the lever of the special device.
Removing the valve springs using a valve spring compressor
Remove valve springs with poppets.
Remove the valve stem seals and spring washers using pliers.
Take out the valves.
Mark the position of parts to be removed so that parts that cannot be replaced can be returned to their original position during assembly.
Clear the details.
Check the degree of wear of the seats of the valve guides and the clearance between the bushings and the valve stems.
Insert the new valve into the guide bush and determine the gap between the end of the stem and the edge of the guide bush using tool VW 387 with an indicator.
Replace guide bushings if clearance exceeds 0.10 mm for intake valve bushings and 0.13 mm for exhaust valve bushings.
Check the flatness of the mating surface of the cylinder head using a metal ruler and a set of feeler gauges.
Grind, if necessary, the mating surface of the cylinder head within acceptable limits (see subsection «Detailed Specifications»).
Check the condition of the valves and valve springs.
Main dimensions for grinding valves and valve seats: Inlet valve: a - angle of the working chamfer (45*); a - the width of the working chamfer; b is the height of the edge of the valve head. Valve seat: a - plane of the cylinder head; a is the diameter of the valve seat. b - distance from the end face of the valve seat to the plane of the cylinder head (valve seat depth); c - width of the working chamfer of the valve seat
Check the condition of the valve seats and grind if necessary. Grinding is carried out with a special tool and within acceptable limits (cm. «Detailed Specifications».
On engine models «DS» release since September 1985 and «NP» when grinding valve seats, keep the minimum distance «A» between the end face of the valve stem and the upper plane of the cylinder head
On engine models «DS» release since September 1985 and «NP» in the case of valve seat grinding, to ensure the normal operation of the hydraulic valve lifters, a minimum distance of ♦a must be maintained» (see picture) between the end of the valve stem and the upper plane of the cylinder head, which for intake valves should be 33.80 mm, for exhaust valves - 34.10 mm.
The shrinkage of the working chamfer of the valve seat must not exceed a value equal to the difference between the value «A» before grinding the valve seat and the minimum value «A» after grinding.
Grind, if necessary, the working chamfers of the inlet valves. The working chamfers of the exhaust valves are not subject to grinding. lapping of exhaust valves is allowed, in other cases they must be replaced.
Thoroughly clean the cylinder head before assembly, and after grinding the valve seats and lapping the valves.
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