Operating the measuring instrument

No. Operation

Prepare measuring instrument for testing

2 Pick up measuring instrument

3 Position measuring instrument

Measure belt tension

Read off measurement

Instructions

Lower pointer into measuring instrument.

Grasp rubber strap between thumb and index finger. Position measuring instrument in center between pul-

The lateral stop of the instrument must rest on the side

Press pushbutton to apply uniform pressure in perpendicular direction on top of V-belt until the detent spring can be heard (or felt) to disengage. After the detent spring has disengaged, the measuring instrument or the pushbutton, respectively, must not be pressed anymore as the reading will otherwise be incorrect.

Lift measuring instrument carefully off the V-belt.

Caution:

Do not push against instrument when lifting off the instrument as sudden impacts may alter the position of the pointer and may give a faulty reading. Read off measurement (tensioning value) at the point of intersection of the pointer with the upper scale (KG

Checking and/or adjusting alternator and fan wheel drive belt Caution: Make sure the ignition key is pulled off whenever measurements are made.

Checking used drive belts:

Use belt tension measuring instrument (Special Tool 9574) to check tension.

A description of how to use the Special Tool is contained in Repair Group 13, page 13-30.

Retensioning the belt is only required if the belt tension displayed at the measuring instrument is less than 15 scale increments when the engine is cold and less than 20 scale increments when the engine

Retensioning the belt

Retension the belt as described in the General Adjustment Notes section. Before measuring the belt tension, start engine and let engine idle briefly.

Tension:

Cold engine: 15 to 23 scale increments

Engine at operating temperature: 20 to 28 scale increments

When fitting a new belt, be sure to observe the correct assembly sequence in order to avoid any loss of belt tension during vehicle

1. Fit new belt. Adjust tension by inserting or removing shims as required.

Shims are available for belt tensioning in thicknesses of 0.5 mm and 0.7 mm. The 0.7 mm shim is identified by a 2 mm dia.

2. Before measuring the belt tension, start engine once more and run engine at idle

Cold engine: 23 to 35 scale increments

3. Run engine at idle for approx. 15 minutes or test drive vehicle for approx. 10 miles. Check tension again. Specification: 28 to 40 scale increments

Test requirement: Engine at operating tem-

General adjustment notes

Fan wheel and alternator have separate drives.

993 Alternator

Note

Rotate engine only at lower belt pulley or by operating the starter. After completing all operations, check to make sure that hexagon head nut has been tightened suffl ciently on alternator shaft.

1863-27

1 = Alternator drive components

2 = Fan wheel drive components

Adjusting the V-belts

1. Use polygon wrench (999 571 052 02) to lock shaft and undo hexagon head nut. Remove shims and pulley half.

2. If belt tension is below specification, remove one shim from between pulley halves and refit in front of pulley half.

Tighten hexagon head nut to 50 ± 5 Nm.

3. Three additional M 6 screws have to be undone for V-belt and fan wheel.

4. Use only V-belts that have been approved

17 00

Lubrication (Engine oil circuit diagram)

Engine Lubrication Circuit
A - Pressure oil circuit B - Return oil circuit C - Breather line D - Electrical system
Circuit Lubrification Turbo Porsche 996

17 00 Lubrication (Engine oil circuit diagram) Printed in Germany -VII, 1994

15 05 06 Checking and adjusting camshafts

(Adjusting the timing) Tools

Porsche 993 Carrera

NO.

Designation

Special tool

Order number

Explanation

9551

000.721.955.10

install 2 fit bolts in the 6H7 holes in the three-hole flange

2

Locking tool for RH camshaft

9552

000.721.955.20

install 2 fit bolts in the 6H7 holes in the three-hole flange

3

Locking tool for crankshaft

9553

000.721.955.30

4

Fit bolt (4 pieces)

9554

000.721.955.40

Install fit bolts in oval hole of three-hole flange

5

Auxiliary chain tensioner

9401

000.721.940.10

6

Pulley retaining wrench

9548

000.721.954.80

(Adjusting the timing) 2. Remove pulley. Undo hexagon head bolt, having a helper lock the pulley with Special Approximate adjustment Tool 9548 (retaining wrench).

1. Rotate crankshaft on pulley until the mark

1. Rotate crankshaft on pulley until the mark

993 Pulley Tool

5. Turn both camshafts until punch mark faces Note

If the mark is missing, rotate camshafts until woodruff key groove points up.

993 Pulley Tool
o

7. When the Z 1 mark on the pulley has been aligned with the seam and when the punch marks or woodruff key groove, respectively, point up, the engine is in the basic firing TDC for cylinder No. 1 and the overlap TDC

6. The camshafts may be aligned and rotated from the front (flywheel end) using Special Tools (locking devices) 9551 or 9552, re-

8. Fit auxiliary chain tensioner (Special Tool Figure shows left-hand side of auxiliary chain

1480-15

Drawing Porsche 993

1480-15

88-550

Note

To adjust or check the timing, the mechanical auxiliary chain tensioners must be fitted with the specified preload. The recess on the plunger must just barely remain visible. Adjusting or checking the timing with a dial gauge is no longer required. The locking tools also serve as adjustment gauges.

Drawing Porsche 993

87-378

Precision adjustment

1. Place locking device 9551 on left-hand camshaft and locking device 9552 on right-hand camshaft and tighten them. Install fit bolts 9554 in oval hole in three-hole flange.

Porsche 993 Drawing
1465-15
Drawing Porsche 993
1461-15

87-378

Drawing shows right side of engine

Note

Adjusting or checking the timing with a dial gauge is no longer required. The locking tools also serve as adjustment gauges. Caution:

At the same time, the locating pin on the chain sprocket or chain sprocket flange is no longer required. However, at the start of production, the locating pin was installed on some engines.

Camshaft Measuring Production
1460-15

Drawing shows rihgt side of engine

2. Apply a thin coat of Optimoly HT to hexagon head bolt threads. Tighten hexagon head bolts of left-hand and right-hand camshafts to 120 Nm (12 kpm).

3. After the adjustment has been completed, remove the auxiliary chain tensioner and refit original chain tensioner. Observe installation position!

944 Timing Belt Tensioner

A - Left-hand chain tensioner. Oil supply hole hole points up.

B - Right-hand chain tensioner. Oil supply hole hole points down.

Note

The spring retainers are additionally marked with „oben" (top) and „unten links" (bottom left) or „unten rechts" (bottom right).

Camshaft drive with single-part chain sprocket flange (four-hole chain sprocktet) (adjust timing)

Tools

Auxiliary Chain TensionerBaseline Vitals Acronyms944 Porsche Bracket

151-03

3. Take off A/C compressor bracket.

993 Pulley Tool

2160-15

151-03

3. Take off A/C compressor bracket.

4. Place Special Tool 9553 (locking device) into position.

(Adjusting the timing) Basic adjustment

Rotate crankshaft at pulley until the pulley mark is exactly in line with the separating joint on the crankcase or the line mark on the blower housing.

2. Undo hexagon head bolt, having a helper use Special Tool 9548 (locking wrench) to lock. Take off pulley.

2160-15

5. Turn both camshafts until punch mark points up.

Porsche Timing Tool 9551 9552

6. Locking tools 9551 or 9552, respectively, may be used to align or rotate the camshafts from the front (flywheel side).

9552

9551

/

ff

\\

(°C

)

1// §

1480-15

993 Pulley Tool
1465-15

7. When mark Z 1 on the pulley is aligned with the separating joint and when the punch marks and/or woodruff key groove of the camshafts point up, the engine will be set to firing TDC of cylinder 1 and overlap TDC of cylinder 4 as a basic adjustment.

8. Fit auxiliary chain tensioner (Special

Fig. shows auxiliary chain tensioner for left side

Porsche 996 Turbo Chain Adjuster
2172-15
88-550

Note

When adjusting or checking the timing, the mechanical auxiliary chain tensioners must be fitted with the specified preload. The groove machined on the thrust piece must be barely visible.

How Measure Woodruff Key
87-378

Precision adjustment

1. Place locking tool 9551 on left camshaft and locking tool 9552 on right camshaft and tighten them. Fit the fit bolts (2 ea.) to the three-hole flange (arrows).

Note

Due to tolerances of the hole pattern of the camshaft housing, the adjustment procedure may differ in some cases:

If the special tools cannot be fitted with 2 fit bolts each, use one fit bolt and one standard M6 bolt to locate them.

In extreme cases (large deviations of the mounting hole pattern on the camshaft housing), standard M6 bolts may be used to locate the special tools. (This will result in slight deviations of the camshaft timing).

Before installing Special Tools 9551 + 9552, check for any burr formation at the 6 H7 holes and at the fit bolts. The fit bolts must be able to rotate in the holes.

Looking For Staff Picture
1465-15
Como Dibujar Una Lata Spray GraffitiTiming Chain 2136
2136-15

The Fig. shows the left side of the engine Note

Adjusting and/or checking the timing with a dial gauge is no longer required. The locking tools are at the same time designed as timing

Kran Ausmalbild

The Fig. shows the right side of the i4eo-i! engine, cylinder bank 4-6

2. Coat threads of hexagon head bolts with a thin coat of Optimoly HT. Tighten hexagon head bolts of left and right

1st stage: Setting torque 20 Nm (15 ftlb.) 2nd stage: Tightening angle 90°

To release the strain on the chain drive and the locking tools, lock with locking wrench (Special Tool 9582) at the chain sprockets when tightening the bolts.

Measuring Instrument Check Runout
2137-15

After completing adjustment, take off auxiliary chain tensioner and refit original chain tensioner. Observe correct installation position.

15 30 37 Dismantling and assembling intermediate shaft

Intermediate Shaft Porsche

15 30 37 Dismantling and assembling intermediate shaft

Note:

No.

Designation

Qty.

Removal

Installation

1

Union shaft

1

Check that shaft runout is within tolerances, shaft must move freely in longitudinal direction.

2

Snap ring 13x1

2

3

Snap ring 36 x 1.75

2

Replace.

4

Chain sprocket

Press off, check teeth. Sprockets are available as spare parts.

Heat on heating plate, push into place to stop, observe installation posh tion.

5

Woodruff key

2

6

Intermediate shaft

1

Matched with crankshaft timing gear, always fit as a complete set.

7

Snap ring 16x1

1

8

Plug, aluminum

1

Remove if bearing damage has occurred, clean bore.

9

Thrust bearing

2

Sliding surface must be oiled, ptacs into crankcase haives.

10

Bearing

2

Sirding surface must be oiled, place into

v ■ I

crankcase halves.

15 . 32 15 30 37 Dismantling and assembling intermediate shaft

15 20 01 Checking intermediate shaft

Checking

Check intermediate shaft gear and timing

2. Check circumferential backlash:

Fit crankshaft and intermediate shaft with new bearings in installation position. Fit VW 387 dial gauge bracket to crankcase mating surface. Take care not to damage sealing surface, use protective support if required.

3. Align dial gauge with one gear tooth and determine backlash.

Rotate intermediate shaft by 180° and repeat measurement.

Sprocket Intermediate Shaft Porsche

Circumferential backlash:

New dimension Wear limit

15 38 19 Removing and installing camshaft housing seal Tool

No.

Designation

Special Tool

Order No.

Explanation

1

Support assembly

9236

000.721.923.60

Camshaft Housing

2007-15

15 38 19 Removing and installing camshaft housing seal

No.

Designation

Removal

Installation

1

Combination screw M 8 x 30

2

2

Combination screw M S x 16

3

3

Cover

1

4

Pan-head screw M 6 x 16. self-locking

3

Apply locking compound if required.

5

Gear

1

Install with toothed belt fitted in place.

S

Toothed belt

1

Mark instalfatjon position

Check, inspect visually for damage.

7

Hexagon-head bolt M 12 x 1.5 x 50

1

Tightening torque 120 Nm, use Special Tool 9236 to lock.

8

Washer A 13

1

9

Gear

1

Install with toothed belt fitted in place.

10

Combination screw M a x 35

2

M 6x 28

3

12

Support housing

1

13

Shaft seal A 30 x 42 X 7

1

Drive in to stop, apply oil to sealing lip.

14

O-ring 40 x 4

1

Replace, oil lightly.

15

Combination screw M & x 16

1

16

Power pump

1

17

Combination screw M 6 x 18

2

18

Mounting bracket

1

Ccmbination screw = Hexagon-head bolt with captive washer

Ccmbination screw = Hexagon-head bolt with captive washer

17 26 38 Removing and installing pressure regulating valves (Pressure

Porsche 964 Oil Pressure Relief Valve

432-17

No

1 Designation

Removal

Installation

Pressure relief valve A

(Crankcase half,

right-hand side)

Plug M 18 x 1.5

1

! ' - f

Tightening torque

.4 -

60 Nm (44 ftlb.)

2

Plunger

1

Use wooden stick to pull

out, if required. Check

plunger and housing

bore for signs of

seizure. Remove

seizure marks carefully,

-

replace plunger if

i

required

3

Thrust spring, 89 mm long

i.

4

Guide sleeve

1

5

Spacer ring

1

Push onto guide

sleeve

6

Seal A 18 x 24

1

Replace

Safety valve B

(Crankcase,

left-hand side)

" if'.'.*"

Plug M 18 x 1.5

1

Tightening torque

•'«!)

60 Nm (44 ftlb.)

2

Seal A 18 x 24

1

Replace

3

Thrust spring 70 mm long

4

Plunger

1

ci : ;

Use wooden stick to pull

out if required. Check

plunger and housing

bore for signs of seizure.

Remove seizure marks

carefully, replace

plunger if required

17 10 30 Cleaning crankcase (oil

The oil passages in the crankcase are plugged (i.e. closed) with sheetmetal covers during production.

Porsche 993 Restoration
1872- 17

If the sheetmetal covers have been removed e.g. to clean the oil passages after bearing damage has occurred, the sheetmetal covers have to be replaced with service aluminum plugs.

Sheetmetal covers have not been released

1873 - 17

Replacement aluminium plugs

The following oversize plugs are available for repairs:

0 23 mm, part no. 911 101 185 01 (2 plugs) Plug (B)

Abelha Cupira
2250-17

Removal

Drill out plug (using a 6.5 mm bit) and tap M8 thread. Pull out plug using a "home-made" extractor consisting of an M8 bolt, spacer ring and washer. Push out the opposite plug, for example using a 10 mm dia. pipe.

Installation

Apply Optimoly HT (copper paste) to plug and press plug in flush.

17 03 01 Checking oil pressure

1. Screw standard oil pressure tester or VW 1342 tester combined with M 10 x 1 fitting and M 14 x 1.5 flange into hole of temperature sender unit in base.

Engine Crankcase Porsche 993

2. Warm up engine to operating temperature (80 °C to 90 °C oil temperature).

Use oil temperature tester (Special Tool 9122 + 9122/2) to check temperature.

3. The oil pressure at idle speed must remain between 2.0 and 2.5 bar. Have a second person raise the engine speed to 2,500 rpm. Read off oil pressure on tester. The reading must be above 5 bar.

4. Fit temperature sender unit with new seal.

15 70 37 Dismantling and assembling cylinder head Tools

Tools

No.

Designation

Special tool

Order number

Explanation

1

Screwdriver insert for polygon head nuts

9295

000.721.929.50

2

Valve spring assembling tool

P200a

000.721.200.10

3

Puller for valve stem seals

3237

000.721.923.70

4

Valve grinder

Standard, e.g. Hazet 765

5

Socket for temperature sensor II in cylinder head (cyl. no. 3)

9291 (SW 14)

000.721.929.10

6

Pressure piece for inserting valve seal

9569

000.721.956.90

70 17 D ntF igan assembf ng cy inder hear!

Exhaust Valve Collet Removal

No.

Designation

Removal

Installation

2

Cylinder head nut Valve collet

4 4

Use screwdriver insert for 9295 polygon-head nut

Apply a thin coat of Optimoly HT to cylinder head nut bearing surface

3

Valve spring retainer

2

4

Valve spring, outer

2

5

Valve spring, inner

2

6

Inlet valve

1

7

Valve stem seal

2

Pull off

Replace, use assembly sleeve

8

Valve spring ring

2

9

Washer

X

10

Exhaust valve

1

11

Valve guide, inlet

1

12

Valve guide, outlet

1

13

Thread insert

2

14

Valve seat insert, inlet

1

15

Valve seat insert, exhaust

1

16

Roll pin

2

Pressed in to stop

17

Cylinder head

1

18

Studs M 8 x 22

2

Fitted with Loctite 270, protruding length 23 - 0.5 mm. Screw studs with unmarked end into cylinder head (exhaust side)

Tightening the cylinder heads Tightening method based on rotating angle

Tools

Tool Repair The Cylinder Head

No.

Designation

Special tool

Order number

Explanation

Gradoscope

Standard, e.g. Stahlwille No. 15/20

Tightening the cylinder heads

Tighten cylinder heads with tightening method based on rotating angle.

Assembly notes

1. Apply a thin coat of Optimoly HT (copper paste) to the stud threads.

2. Fit cylinder heads.

3. Apply a thin coat of Optimoly HT to the cylinder head nuts and tighten them as follows:

Tightening in two steps:

1st step: 20 Nm (18 ftlb.) according to specified tightening sequence

2nd step: 1 x 90" ± 2* in identical sequence

Porsche 993 Knock SensorPorsche Knock Sensor Bridge
435-15

4. Tighten knock sensor bridges to a final

Where The Knock Sens P11

Note

The hexagon head bolts of the knock sensor bridge should only be screwed in manually before tightening the cylinder heads.

15 59 04 Measuring valve lifters

Each time valve seats or valves are machined, the lift of the valve lifters must always

The following parts are needed for the test

1 intake rocker arm 1 exhaust rocker arm

(the valve lifters must be free from oil; clean them in petroleum spirit)

Note: These parts should only be used for checking valves and lifters and must therefore be appropriately marked and stored separate-

original rocker arm shafts fastening screws dial gauge mount (VW 387) dial gauge

Measurement

Set piston to TDC, at which point the valves are closed. If the timing chain is not installed, turn the camshaft until the rocker arms are within the circle of the cam.

2. Push rocker arm by hand and read valve lift

John Deere X748 Mower Belt Diagram

The lift must be at least 0.2 mm on the in-

take rocker é haust rocker arm

If the valve lift measured is lower than the figure specified, a special, shorter replacement valve lifter must be installed.

Replacement valve lifters are available in

Size 1: 0.5 mm shorter

Part No. 993 105 141 50

Size 2.1.0 mm shorter

Part No. 993 105 141 60

Caution:

The lift must not exceed

1.85 mm on the intake rocker arm

2.25 mm on the exhaust rocker arm!

15 75 02 Checking valve guides

1. Clean valve guides thoroughly

2. Use a new valve to measure the tilting play

3. Fit dial gauge holder VW 387 to cylinder head. The dial gauge must be aligned parallel to the valve head.

993 Porsche Cylinder Head
1763-15

4. The tilting play is measured at a valve lift of 10 mm (clearance from valve head to valve seat).

Wear limit for inlet guide = 0.80 mm exhaust guide = 0.80 mm

Note

Any ovaiity in the entry section of the valve guides may be disregarded.

15 75 02 Checking valve guides

15-8a

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