928 S V8-4957cc 5.0L (1985)
Camshaft: Service and Repair
1.
Disconnect battery ground cable.
2.
Remove crossmember.
3.
Remove air cleaner assembly with intake hoses.
4.
Remove intake air distributor.
5.
Remove distributor cap, distributor rotor, timing belt upper section and the cylinder head cover.
6.
Turn crankshaft clockwise to align 45° before TDC mark (cylinder No. 1) on vibration damper with cast boss of center timing belt cover. At 45°
mark, camshafts can be turned without damaging valves.
7.
Loosen timing belt with tensioner and remove belt from camshaft sprocket.
8.
Remove camshaft attaching bolt, then the sprocket, drive hub and woodruff key from exhaust camshaft.
9.
Remove rear timing belt cover.
10.
Set marks on camshafts to face up by turning exhaust camshaft with suitable tool.
11.
Remove timing chain tensioner. Tensioner piston has spring force. Compress piston for removal and hold together with suitable piece of wire after
removing.
12.
Secure camshafts in bearings using tool 9226 or equivalent and remove bearing bridges and caps.
13.
Release tool uniformly and remove camshafts together with timing chain.
14.
Place camshafts in timing chain so that marks on camshafts or cast bosses are aligned with marked chain links, then lubricate bearing surfaces with
oil and carefully place timing chain in bearings.
15.
Mount camshafts on cylinder head using tool 9226 or equivalent.
16.
Install bearing bridges and bearing caps, torquing to 7 ft.lbs. Bearing bridges and caps are machined together with cylinder head and must
always be installed in correct position. Ensure that codes and pairing numbers match.
17.
Coat sealing surfaces of front and rear double bearing bridges with suitable locking compound.
18.
Recheck camshaft position using gage from tool 9226, or equivalent.
19.
Using tools 9233 and 9234, or equivalents, drive seal on to drive end of camshaft. Lubricate sealing lip before installing.
20.
Reverse remainder of removal procedure to complete installation, then adjust camshafts as follows:
a. Turn engine in operating direction to TDC (cylinder No. 1) and ensure both distributor rotors face left, marks on camshaft sprockets and
flange bearings are aligned, and marks on camshafts face exhaust side.
b. Mount dial gage with holder VW388 or equivalent on cylinder head. Set dial gage on hydraulic lifter of cylinder No. 1 intake valve to 0 with
5 mm preload.
c. Set dial gage on hydraulic lifter of cylinder No. 6 intake valve and zero indicator. Dial gage must be aligned perpendicular to intake valve.
d. Turn crankshaft further from TDC while observing dial gage. Turn until a value of 1-3 mm lift is obtained and ensure mark for 20° after TDC
(cylinder No. 6) is aligned with pointer on timing belt cover. If alignment is not correct, proceed to step e.
e. Install three M5 x 15 screws in camshaft sprockets to prevent sprockets or camshafts from turning.
f.
Turn crankshaft in operating direction until dial gage shows 1-3 mm lift.
g. Remove camshaft attaching bolts while counter holding then remove M5 screws.
h. Turn crankshaft to 20° after TDC (cylinder No. 6).
i.
Install camshaft sprockets, first installing three M5 x 15 screws, then torquing attaching bolts (M10) to 47 ft.lbs.
j.
Turn crankshaft 720°, then recheck adjustment. Reading should be 1-3 mm at 20° after TDC for cylinder No. 6. Repeat adjusting procedures
as necessary.
k. Remove M5 x 15 screws.