Engine, Cylinder Head, Valve Drive
ENGINE, CYLINDER HEAD, VALVE DRIVE
CAUTION: Coolant/antifreeze must not be reused when replacing engine, cylinder head, cylinder head gasket, radiator and heater core.
NOTE:
Cylinder heads with cracks between valve seats or between a valve seat and spark plug thread can be used again without reducing service life provided that cracks are small and not more than 0.5 mm (0.019 in.) wide or that only first coil of plug thread is cracked.
Cylinder head can be removed and installed with engine installed.
Cylinder Head:
Valves, Springs, Dimensions, Refacing
Fig. 1 Valve Springs, Removing/installing:
Fig. 2 Valve, Dimensions:
CAUTION: Do not rework lap by hand only.
Fig. 3 Intake Valves, Refacing:
valve margin d must not be less than 0.5 mm (0.020 in.)
Valve Seats, Refacing - Work Sequence
CAUTION: Damaged or burnt seats can be refaced if:
permissible width of seat A is maintained
15° chamfer B does not exceed outer diameter of valve seat insert in cylinder head at C
- seat width a = 1.4-2.5 mm (0.055-0.098 in.)
Valve Seats, Refacing
- reface valve seats to 45° angle, stop cutting as soon as complete seat is cleaned
- reface surface to 75° angle slightly chamfer lower edge of valve seat
- reface surface to 15° angle chamfer upper edge of valve seat until correct seat width is obtained
NOTE: When new valves are installed in properly reworked seats, it may not be necessary to lap in valves.
CAUTION: After lapping valve, remove grinding paste.
Valve Guides, Checking
NOTE:
When repairing engines with leaking valves it is not sufficient to rework or replace valve seats and valves.
It is also necessary to check valve guides for wear.
This is particularly important on engines which have considerable mileage.
- remove carbon
- insert new valve into valve guide valve stem must be flush with valve guide end
- rock valve back and forth against dial indicator (arrow) max. 1.2 mm (0.047 in.)
Cylinder Head, Assembly:
Engine Block, Assembly:
Cylinder Head Hydraulic Valve Lifters
Fig. 1 Pushrod Tube, Pretensioning:
- pretension tube to correct length
a = approximately 194 mm (7.6 in.)
- when installing, seam faces upward and small end to cylinder head
- always replace sealing rings, head gasket
pushrod tubes can be replaced with engine installed
Applying sealant D 000 400 O1
Fig. 2 Cylinder Head, Sealing:
To improve sealing of painted/unpainted sealing surfaces on cylinder head, use D 000 400 sealant.
- if paint is damaged, clean cylinder head sealing surface with fine sand paper
- clean sealing surface with solvent
- apply 1 to 2 mm (3/64-5/64 in.) bead of sealing compound D 000 400 in the center of the new water jacket gasket (arrows)
CAUTION: DO NOT USE TOO MUCH SEALANT. Excessive sealant could plug cylinder head coolant passages or hydrolock cap nuts.
NOTE: Cylinder head must be installed within 45 minutes of the sealant application.
Fig. 3 Cylinder Head, Installing:
- tighten cylinder head at stud 1 with cap nut just enough so that all remaining 7 cap nuts can be installed
- coat surface of cap nut with AKD 456 000 O1 sealing compound
Torque Sequence
CAUTION: Do NOT use click type torque wrench only beam or dial type wrench.
First stage. tighten cap nuts in numbered sequence (see above) to 10 Nm (7 ft lb)
NOTE: Be sure that push rod tubes are properly seated.
Second stage: tighten cap nuts, in numbered sequence to 50 Nm (37 ft lb)
- recheck final 50 Nm (37 ft lb)
- reinstall push rods, rocker arms
push rods must be properly seated before tightening rocker arms
torque: 25 Nm (18 ft lb)
Hydraulic Valve Lifters, Adjusting
NOTE:
Never repair valve lifters: if worn or damaged, replace complete assembly.
Valve lifters can be removed and replaced without engine removal and without major engine disassembly.
Intermittent valve noises are normal upon starting, sudden acceleration, high temperatures or high engine speed.
CAUTION: If metal particles are found in oil pan, remove, disassemble, clean and reinstall all valve litters from position removed.
- guide pushrod carefully into socket of hydraulic valve litter
If rocker shafts have been removed, the following adjustment is necessary:
- back out adjusting screws in rocker arms until ball shaped end is flush with surface of arm
- turn crankshaft until cylinder No.1 is at TDC (mark on rotor in line with mark on distributor housing)
- turn adjusting screws in until they just touch valve stems
- turn adjusting screws 2 turns clockwise and tighten lock nuts
- rotate crankshaft 180° and adjust next cylinder
- repeat until all cylinders are adjusted
Hydraulic Valve Lifters, Bleeding
- before installing, ensure valve litter is bled correctly
check by applying firm thumb pressure on push rod socket in direction of arrow. Litter should not move.
If NO, bleed lifter as follows:
- pry out lock ring
- remove pushrod socket, plunger, ball check valve with spring, check valve retainer and plunger spring from body
- fill valve lifter body with oil up to bleed hole
- insert plunger spring
- install plunger with ball check valve, spring and valve retainer and push downward; at same time, open ball check valve with scribe
- insert pushrod in socket and slowly press together with valve guide or sawed-off pushrod in vise (bore A must face upward) or in press until lock ring can be installed
- install lock ring
Pushrod Tubes, Replacing
NOTE: Pushrod tubes supplied as replacement parts can be installed with engine in place.
- remove valve cover
- remove rocker arm shaft, pull pushrod out
- remove lower cover plate
- remove defective pushrod tube with pliers or screwdriver
- squeeze new pushrod tube together and insert with new sealing rings as shown (arrow) (tube seam faces upward, small end to head)
- insert pushrod and install rocker arm shaft
CAUTION:
Guide pushrod carefully into seat of hydraulic valve lifter.
If pushrod rests on edge of lifter basic setting will be incorrect and lifter will be damaged when engine is started.
- adjust hydraulic valve lifters
Cylinder Head, Resealing
NOTE: To reseal cylinder heads, follow this procedure. Always do both sides. Cylinder heads can be removed without removing the engine.
Removing
- disconnect battery ground strap
- remove rear mattress (where applicable), carpet, engine cover
- remove air cleaner assembly
- remove A/C compressor from bracket, leave hoses attached
WARNING: Fire hazard. Do not smoke or have anything in area that can ignite fuel.
- remove left/right fuel rails, injector ground wires and intake manifolds
- remove left/right splash shields
- remove push rod tube shields
- disconnect oxygen sensor
- remove coolant drain plugs 1 at both cylinder heads, drain coolant from engine
- drain engine oil, remove oil filter
NOTE: Do not reinstall oil drain plug until repair is completed.
- remove spare tire cover under front of vehicle, disconnect coolant hoses
- reconnect radiator coolant hoses
- close spare tire cover
- remove coolant pump
- remove exhaust system, including crossover pipes, muffler with converter and exhaust heat shield
- remove crankshaft pulley
- remove power steering pump
- remove coolant cross-over pipes at front! rear of cylinder head
- remove valve covers, rocker arms, push rods, oil filler pipe
NOTE: Mark push rods for reinstalling to original location.
- remove cylinder head cap nuts, push rod tubes and cylinder head
- stuck cylinder sleeves may be removed by lightly tapping with small solid rubber mallet
- clean old gasket material from cylinder heads, engine block, valve covers
- inspect sealing surface of cylinder head, replace if pitting or cavitation present
- mark matching numbers on piston/cylinders
- pull out cylinder sleeves with tool 3092 until piston circlip is visible
- remove piston circlips, wrist pins with tools 3091, 3159
Installing
CAUTION:
Always replace gaskets, seals, 0-rings, lubricants.
Part numbers are listed for reference only. Always consult with the Parts Department for latest information.
- inspect cylinder head studs for corrosion, and replace as required
- clean wrist pins, cylinder sleeves, pistons
- replace both cylinder sleeve 0-rings
- reinstall piston and cylinder sleeve onto corresponding connecting rod
- install wrist pin to connecting rod
- clean push rod tubes, rocker arms, valve covers, cylinder head cap nuts
- measure and adjust push rod tubes to length a
a = approximately 194 mm (approximately 7.6 in.)
- install new cylinder head gasket
CAUTION: Do not use too much sealant. Excessive sealant could plug cylinder head coolant passages or hydrolock cap nuts.
- apply cylinder head sealant Part No. D 000 400 O1 in 1.0-2.0 mm (3/64-5/64 in.) bead (arrows) in center of gasket side facing cylinder head
- install cap nut location in 1.0 mm (3/64 in.) bead
- reinstall cylinder heads, push rod tubes, seam side up
CAUTION: DO NOT use click type torque wrench. Use only beam or dial torque wrench.
- tighten cylinder head at stud 1 with cap nut just enough so that remaining 7 cap nuts can be installed
Torque Sequence
NOTE: Ensure that push rod tubes are properly seated.
- First stage: tighten cap nuts in numbered sequence to 10 Nm (7 ft lb)
- Second stage: tighten cap nuts in numbered sequence to 40 Nm (30 ft lb)
- Third stage: tighten cap nuts in numbered sequence to 50 Nm (37 ft lb)
- recheck final 50 Nm (37 ft lb)
- reinstall push rods, rocker arms
- push rods must be properly seated before tightening rocker arms
torque: 25 Nm (18 ft lb)
Hydraulic Valve Lifters, Adjusting
- back out adjusting screws in rocker arms until ball shaped end is flush with surface of arm
- turn crankshaft until cylinder No.1 is at TDC
- mark on rotor must be in line with mark on distributor housing
- turn adjusting screws in until they just touch valve stems
- turn adjusting screws 2 turns clockwise and tighten lock nuts
- rotate crankshaft 180° clockwise and adjust next cylinder
- repeat until all cylinders are adjusted
- reinstall all other components in reverse order of removal
- check expansion tank pressure cap with VAG 1274/99
- refill with coolant
- reinstall engine drain plug, refill with oil
- reconnect battery ground strap
- remove radiator grille
- raise front of vehicle approximately 40 cm (16 in.) under cross member
- bleed air from coolant system
- lower vehicle to ground
- reinstall radiator grille
- pressure check cooling system for leaks with tool VAG 1274/99
- check and adjust engine specifications, as necessary