Cylinder Heads

GENERAL 150-1

Special tools 150-1

CYLINDER HEADS 150-2

Cylinder head service 150-3

VALVES 150-4

Valve guide, checking 150-4

Valve guide, replacing 150-4

Valve seat, checking 150-5

Valve seat, replacing 150-5

Valve seat, cutting 150-6

Valves 150-6

Valve spring height, setting 150-6

TABLES

a. Valve Guide Outside Diameters 150-4

b. Valve Seat Dimensions 150-6

c. Valve Seat Cutting Guide 150-6

d. Valve Specifications 150-6

Special Tools

1984 911 Seat

Special tool

A 1020 (source: Baum Tools Unlimited) Valve spring compressor

B P 206 Valve guide go/nogo gauge

(Porsche ordering #000 721 206 00) C 87a (source: Baum Tools Unlimited) . Valve guide removal drift D 83 (source: Baum Tools Unlimited) Valve guide installation drift E 10-204 (source: Baum Tools Unlimited)Valve stem seal installer

F P10c Valve spring height gauge

(Porsche ordering #000 721 010 30)

GENERAL

This repair group provides reconditioning information for the cylinder heads, including valvetrain reconditioning specifications.

Cylinder head repair and reconditioning require that the engine be removed from the car and disassembled on an appropriate engine stand. Engine disassembly is described in 102 Engine Disassembly and Assembly.

CAUTION—

The information contained in the repair group is intended to be used as a reconditioning guide for the professional or experienced automotive technician.

Special tools

^ Some of the procedures require special tools.

CYLINDER HEADS

Five of the cylinder heads are identical. Cylinder head 3 has a threaded boss for the temperature sensor.

Lower Seat Cylinder Head

1. Valve

2. Valve seat

3. Cylinder head

4. Valve guide

5. Valve spring seat shim

6. Valve spring seat

7. Valve stem seal

8. Outer valve spring

9. Inner valve spring

10. Valve spring retainer

11. Valve keeper

12. Spark plug threaded insert

13. Cylinder head washer

14. Cylinder head nut (8 mm alien)

Cylinder Head 993

Cylinder head service

Remove and install valve springs using Porsche special tool P 200 a or equivalent.

Keep parts for each valve assembly (keepers, springs, spring retainer etc.) together.

— On cylinder head no. 3: remove temperature sensor using Porsche special tool 9222/1 or equivalent.

— Wash cylinder head and clean thoroughly by bead blasting. NOTE —

Check sealing surfaces on cylinder head prior to cleaning. If any head studs were found to be broken during disassembly, check carefully for damage to the castings caused by blow-by.

Inspect cylinder head sealing surface. Cylinder heads can be machined, providing the following rules are adhered to:

• Mill surfaces A and B equal amounts.

• Mill all three heads on each side an equal amount.

• Bevel edges of machined surfaces slightly.

• Mark cylinder head with "-25", indicating that head was machined.

Cylinder Head Machining Limit

• Mill surfaces A and B . 0.25 ± 0.02 mm (0.01 ± 0.001 in.)

• Cylinder head surface may only be machined once.

• When assembling an engine with machined cylinder heads, be sure to use thicker 0.50 mm (0.02 in.) base gaskets. The 0.50 mm gaskets are available from an authorized Porsche parts department.

VALVES

Valve guide, checking

Use Porsche special tool P 206 (valve guide go/nogo gauge) or bore gauge/micrometer to check guide for wear. Check against specification.

Valve Guide Wear Limit

• Intake valve guide inside dia. to intake valve stem clearance 0.15 mm (0.006 in.)

• Exhaust valve guide inside dia. to exhaust valve stem clearance 0.20 mm (0.008 in.)

440 Valve Guides

Valve guide, replacing

— Working from camshaft side, machine away top of valve guide flush with top of cylinder head.

— Dislodge each valve guide with sharp blow from a hammer.

— Press guide out through combustion chamber using an appropriate drift.

^ Measure guide bores in cylinder head. Machine replacement valve guides so that valve guide diameter is 0.06-0.09 mm (0.0023-0.0035 in.) larger than valve guide hole.

When the valve guides are removed, the bores in the cylinder head will most likely be widened. Replacement valve guides from Porsche are oversized and must be machined (turned on a lathe) so that an interference fit is obtained.

Table a. Valve Guide Outside Diameters

Valve guide

Guide outside diameter (A)

Standard size

13.060 mm (0.514 in.)

Oversize 1

13.260 mm (0.522 in.)

Porsche Valve SizesCobb AnglePorsche 911 Valve Guide Removal

^ Apply lubricant (tallow-based) to valve guide and press new guides in to specified installed height using 9 mm stepped drift.

Valve Guide Installed Height

• Height above cylinder head (B)____13.2 mm (0.520 in.)

• Reamed diameter (C) 9.00 - 9.015 mm (0.354 - 0.355 in.)

— Ream new valve guides with special tool no. 78HSS (9 mm)

Valve seat, checking

Place valve in cylinder head and measure distance between top of valve stem and valve spring seat (shims removed).

Valve Seat Check

• Valve seat checking height D 46.0 ± 0.3 mm (1.811 ± 0.011 in.)

— If dimension D exceeds specifications, recheck with new valve. If measurement is still out of specifications, replace valve seat or cylinder head.

Valve seat, replacing

— Use rough cut stone to carefully grind away valve seat until seat becomes loose in cylinder head. Remove seat.

^ Measure valve seat outer diameter d1. Measure cylinder head bore diameter D1.

— Machine replacement valve seats so that seat diameter is larger than valve seat hole according to fit specifications. See Table b.

— Install valve seat using appropriate drift.

— Allow cylinder head to slowly cool to room temperature.

— Reheat cylinder head to 200° C (400° F) and maintain temperature for 2 hours.

— Allow cylinder head to slowly cool to room temperature.

Table b. Valve Seat Dimensions

Valve Seat

Valve seat diameter (d1)

Cylinder head bore diameter (D1)

Standard size Intake seat

Exhaust seat

51.680-51,661mm (2.0346 - 2.0339 in.) 44.200 - 44.184 mm (1.7402-1.7395 in.)

51.500 - 51.530 mm (2.0276 - 2.0287 in.) 44.000 - 44.025 mm (1.7323-1.7333 in.)

Oversize 1 Intake seat

Exhaust seat

52.000-51.981 mm (2.0472 - 2.0465 in.) 44.760 - 44.744 mm (1.7622-1.7616 in.)

51.820-51.850 mm (2.0401 -2.0413 in.) 44.560 - 44.585 mm (1.7543-1.7553 in.)

Valve seat to cylinder head clearance (interference fit) Intake valve Exhaust valve

-0.16 to -0.20 mm (-0.0063 to 0.0078 in.) -0.14 to -0.18 mm (-0.0055 to 0.0071 in.)

Porsche 911 Valve Seat Cut

Valve seat, cutting

Use illustration and Table c as guide in cutting valve seat. Table c. Valve Seat Cutting Guide

Intake valve/exhaust valve

Valve seat angle (a)

45°

Valve seat lower edge (b)

75°

Valve seat upper edge (c)

30°

Valve seat width (d)

1.5 ± 0.1 mm (0.059 ± 0.004 in.)

Valves

^ Use illustration and Table d for valve specifications and measurements.

Table d. Valve Specifications

Dimension

Intake

Exhaust

Valve head diameter (a)

49.00 ±0.10 mm (1.929 ±0.004 in.)

41.5 ±0.10 mm (1.634 ±0.004 in.)

Valve stem diameter (b)

8.97-0.012 mm (0.3531 - 0.0004 in.)

8.95-0.012 mm (0.3523 - 0.0004 in.)

Total valve length

(e)

110.1 +0.25 mm (4.335 ±0.010 in.)

108.4 ±0.25 mm (4.268 ±0.010 in.)

Valve seat angle (d)

45°

911 Valve Spring Cap

Valve spring height, setting

Keep each set of valves, springs, keepers and spring retainers with the cylinder head that they came out of. Check both inner and outer springs for damage. The outer valve spring is progressively wound and should be installed with the tighter coils resting on the cylinder head. The inner spring can be installed either way.

^ Use Porsche special tool P 10 c or equivalent to measure distance A.

• Adjust valve spring height by adding or subtracting shims under valve spring.

♦ Correct valve spring height to specifications listed.

Valve Spring Height Specification

• Intake or exhaust (A) ... 34.5-0.3 mm (1.358-0.012 in.)

130 Crankcase and Crankshaft

GENERAL 130-1

Special tools 130-1

CRANKSHAFT OIL SEALS 130-2

Front crankshaft oil seal

(pulley end), replacing 130-2

Rear crankshaft oil seal (flywheel end), replacing 130-3

CRANKCASE 130-4

Crankcase, inspection 130-5

Intermediate shaft, inspection 130-7

CRANKSHAFT AND

CONNECTING RODS 130-9

Crankshaft gears, removing and installing... .130-9

Crankshaft main and rod bearings 130-10

Connecting rods 130-11

TABLES

a. Intermediate Shaft Clearances 130-8

b. Crankcase/Gear Assembly Code 130-9

c. Crankshaft Gear Circlip Thickness 130-10

d. Crankshaft Journal Sizes 130-11

e. Crankshaft Clearances 130-11

f. Connecting Rod Weights 130-12

g. Connecting Rod Dimensions 130-12

Special Tools

Porsche Pulley Oil Seal 1984 Porsche 911 Crankshaft

Special tools

A 9236 Pulley holding spanner wrench

(Porsche ordering #000 721 923 60)

B 681 Oil seal puller

(source: Baum Tools Unlimited)

C P 216 a Pulley end oil seal installer

(Porsche ordering #000 721 216 10)

D 9126 Flywheel end oil seal installer

(Porsche ordering #000 721 912 60)

GENERAL

This repair group provides reconditioning information for the crankcase, crankshaft and intermediate shaft. Engine disassembly is described in 102 Engine Disassembly and Assembly.

The information contained here is intended to be used as a reconditioning guide for the professional or experienced automotive technician.

Special tools

Some of the procedures require special tools.

Special Tools

Porsche 928 How Remove Engine

Special tool

E P 370 Clutch spline aligning tool

(source: Baum Tools Unlimited)

F 17 Dial bore gauge 50-150 mm

(source: Baum Tools Unlimited)

G P 209 a Bracket for holding crankshaft in vise

(Porsche ordering #000 721 209 10)

H 12 Micrometer

(source: Baum Tools Unlimited)

CRANKSHAFT OIL SEALS

The pulley end of the engine is referred to as the front. The flywheel end of the engine is referred to as the rear.

Front crankshaft oil seal (pulley end), replacing

The front crankshaft oil seal can be replaced with the engine installed in the vehicle.

— Remove alternator and A/C compressor belts. See 270 Battery, Starter, Alternator.

— Remove pulley mounting bolt and remove pulley. NOTE —

Use Porsche special tool no. 9236 to counter hold pulley.

— Remove crankshaft oil seal with Porsche special tool no. 681 or equivalent.

^ Using Porsche special tool P 216 or equivalent press new seal into position.

Porsche Pulley Oil Seal

0018638

Lubricate inner lip of new seal with engine oil prior to installation.

— Install pulley and bolt. Counterhold pulley when tightening bolt.

Tightening Torque

— Install alternator and A/C compressor belts.

Rear crankshaft oil seal (flywheel end), replacing

Replacement of the rear crankshaft oil seal requires that the engine be removed from the car and the transmission be separated from the engine.

— Remove engine and transmission and separate transmission from engine as described in 101 Engine Removal and Installation.

— Remove clutch mounting bolts and remove clutch pressure plate and disc.

— Remove flywheel bolts and remove flywheel.

— Remove crankshaft oil seal with Porsche special tool no. 681 or equivalent.

Using Porsche special tool no. 9126 (arrow) or equivalent press seal into crankcase.

Lubricate inner lip of new seal with engine oil prior to installation.

— Reinstall flywheel and clutch using Porsche special tool no. P370 or equivalent to align clutch disc.

Tightening Torques

— Join transmission and engine and reinstall. See 101 Engine Removal and Installation.

Tightening Torques

• Crankcase to transmission 48 Nm (36 ft-lb)

911 Engine Tightening

0018674

CRANKCASE

All disassembled parts should be thoroughly cleaned before inspection. If bearings are to be reused, they should always be reinstalled in their exact positions. Parts should never be interchanged between cylinders.

• When cleaning engine parts always wear eye protection.

• Solvents used for cleaning parts are highly flammable, especially in aerosol form. Use with care. Do not smoke. Do not use these products near any source of sparks or flame.

41 43

Oil Sensor Temperature Porsche 997

1. Oil pressure switch, 20 Nm (15 ft-lb)

4. Oil thermostat

6. Case bolt sealing ring

7. Case bolt beveled washer

9. Crankcase

10. Case bolt

11. Oil pressure sensor, 35 Nm (26 ft-lb)

12. Oil pressure sensor sealing ring,

(18x24 mm)

13. Oil pressure sensor adapter bolt,

14. Adapter bolt sealing ring. (12x16 mm)

15. Transmitter adapter housing

16. Oil temperature sensor,

17. Temperature sensor sealing ring

19. Front pulley

20. Intermediate shaft cover bolt

21. Intermediate shaft cover bolt washer

22. Intermediate shaft cover

23. Crankshaft oil seal, front

24. Chain guide rail bolt

25. Guide rail bolt sealing ring (10x16 mm)

26. Chain guide rail

28. Drain plug sealing ring, (22 x 27 mm)

29. Oil pressure relief valve piston

30. Oil pressure relief valve spring

31. Oil pressure relief valve sleeve

34. Line adapter sealing ring, (22 x 27mm)

36. Oil pressure safety valve spring

37. Cylinder head alien nut

38. Cylinder head washer

39. Cylinder head stud

40. Crankshaft oil seal, rear

41. Flywheel

42. Heater blower after-run temperature switch, 25 Nm (18 ft-lb)

43. Temperature switch sealing ring

44. Breather cover

45. Breather cover gasket

Crankcase assembly

41 43

Porsche Lubrication Circuit

Crankcase, inspection

^ On engines that have had a mechanical failure, the complete lubrication circuit must be cleaned and flushed to remove foreign material before reassembling the engine. This includes cleaning all oil lines, oil pressure valves, crankcase oil passages (arrows) and oil reservoir. In addition to thorough cleaning, the engine oil coolers should be replaced. See 170 Engine Lubrication.

^ Check cast oil pipe webbing in right crankcase half (lower oil cooler area) for oil leakage due to porous casting material.

• To repair, thoroughly clean crankcase in problem area using alcohol or acetone.

• Fill area with Silastic® 732 RTV sealing compound or equivalent using light uniform pressure until depression is filled.

1989 Porsche 911 Check Engine Light

^ Check for oil leakage at upper right mounting stud at rear engine carrier (arrow). If oil is present, metal between engine oil passages and stud hole threads may be porous. To correct this problem, replace M10 x 22 mm mounting stud with M10 x 15 mm stud, securing with Loctite®270.

Sealing Compound 440

0018800

Using Joint Compound Journals

Blow out all engine crankcase oil feed bores (arrows) with compressed air.

Install left half of crankcase and tap into place.

• Install all M10 crankcase bolts, washers and nuts.

• Install four M8 nuts on bearing 1 (flywheel end) and bearing 8 (pulley end).

• Finger tighten nuts.

• Align case sections with each other with light knocks from a plastic hammer. Bearing bore 8 joint must not be offset.

• Tighten all case bolts and nuts to specified torque.

Tightening Torques

• Crankcase bolts and nuts (M10) 35 Nm (26 ft-lb)

• No. 1 and 8 main journal nuts (M8) 25 Nm (18 ft-lb)

Measure bearing bores 1 to 8 with an internal micrometer. Check for wear, scoring or out of roundness.

Case Bore for Main Bearings (bearings removed)

Case Bore for Intermediate Shaft (bearings removed)

• Bearing 1 27.500-27.521 mm (1.0827-1.0835 in.)

• Bearing 2 26.500-26.521 mm (1.0433-1.0441 in.)

901 Intermediate Shaft

Intermediate shaft, inspection

— Inspect intermediate shaft drive gear for wear or damage.

^ Measure gear by placing two 4.5 mm dowel pins (or drill bits) in gear teeth 180° apart.

• Replace intermediate shaft with drive gear if measurement A falls below specifications.

Intermediate Shaft Drive Gear Specifications

Intermediate shaft drive gear code is stamped on machined face of gear.

— Check shaft for wear or damage. See Table a.

Table a. Intermediate Shaft Clearances

Journal dia. bearing 1

bearing 2

25.000 - 24.980 mm (0.9842 - 0.9835 in.) 23.980 - 23.967 mm (0.9441 - 0.9436 in.)

Intermediate shaft clearance (Plastigage®)

0.030 - 0.084 mm (0.00012-0.0033 in.)

Intermediate shaft axial clearance Wear limit

0.040 - 0.133 mm (0.0016-0.0052 in.) 0.16 mm (0.0063 in.)

The intermediate shaft and aluminum drive gear are one replacement part.

Intermediate shaft

Porsche Bearing Intermediateshaft

0018040

The intermediate shaft and aluminum drive gear are one replacement part.

Crankcase, drive gear on crankshaft, and drive gear on intermediate shaft are assembled as a coded set (arrows). This assembly code is based on the case bore centers. When replacing drive gears, note the code on the gear and use a gear with the same code. Additionally, the bore centers should be checked before final assembly as described below.

Measure distance between centerline of crankshaft and intermediate shaft bores (A).

• Match gears and crankcase as shown in Table b.

— The intermediate shaft is hollow and should be cleaned out whenever the engine is being reconditioned and in case of engine bearing failure.

• Drill 6.4 mm (0.252 in.) diameter hole in aluminum plug located in end of intermediate shaft. Tap hole with M8 tap.

• Install M8 X125 mm bolt into drilled hole and pull aluminum plug out of shaft.

• Flush residue from inside shaft and install new plug.

Intermediate shaft

0018040

Crankshaft

Table b. Crankcase/Gear Assembly Code

Distance A

Crankcase code

Crankshaft drive gear code

Intermediate shaft gear code

Backlash

103.975-103.990 mm (4.0935- 4.0941 in.)

0

0

0

0.029 - 0.049 mm (0.0011 - 0.0019 in.)

installation permitted

1

0

0.016 - 0.042 mm (0.0006 - 0.0016 in.)

0

1

0.017 - 0.043 mm (0.0006 - 0.0017 in.)

103.990-104.000 mm (4.0941—4.0945 in.)

1

1

1

0.012 - 0.041 mm (0.0004 - 0.0016 in.)

installation permitted

0

1

0.025 - 0.049 mm (0.0009 - 0.0019 in.)

1

0

0.025 - 0.048 mm (0.0009 - 0.0019 in.)

One Gear Shaft With Key And Shoulder

0018325

CRANKSHAFT AND CONNECTING RODS

— Bolt crankshaft in special mounting tool (special tool P 209) and mount in a shop vise.

— Remove circlip holding gears on crankshaft.

^ Remove complete gear assembly from crankshaft with a suitable puller. Check gear bore and shaft diameter (interference fit).

^ Install drive gear to crankshaft.

• Install woodruff key to crankshaft.

• With shoulder on gearfacing in (arrow), slide drive gear fully onto crankshaft.

Crankshaft gears, removing and installing

Crankshaft Drive Gear Fit

• Timing gear shaft dia 42.002-42.013 mm (1.6536 - 1.6540 in.)

• Timing gear bore dia 41.975-42.000 mm (1.6526 -1.6535 in.)

• Fit tolerance -0.002 to -0.038 mm (-0.00008 to -0.0015 in.)

0018325

Use protective gloves or shop rag when handling the hot gear.

911 Porsche Distributor Shaft

0018327

Crankshaft assembly

Cylinder Spacer Longer Connecting Rod

7. Crankshaft

8. Woodruff key

9. Connecting rod

10.Connecting rod bearing

11. Main bearing

Crankshaft assembly

-flc

1. Pulley bolt

3. Circlip

4. Distributor drive gear

5. Spacer

6. Intermediate shaft drive gear

7. Crankshaft

8. Woodruff key

9. Connecting rod

10.Connecting rod bearing

11. Main bearing

Install spacer to crankshaft.

— Install distributor drive gear to crankshaft.

• Heat gear to 100°C (212°F) in water bath. Install gear to crankshaft with gear mark facing out.

Use protective gloves or shop rag when handling the hot gear.

Be sure marking on distributor drive gear faces V-belt drive pulley end of crankshaft. Incorrect installation will cause initial ignition timing to be off by approximately 13°.

^ Install selective circlip to crankshaft so that zero clearance is best obtained.

Circlip used to hold gears in place on crankshaft comes in different thicknesses. See Table c. Select circlip to best obtain near zero clearance.

Table c. Crankshaft Gear Circlip Thickness

Porsche P/N

Thickness

Marking

901 102 148 00

2.4 mm

0

901 102 148 01

2.3 mm

1

901 102 148 02

2.2 mm

2

901 102 148 03

2.1 mm

Porsche Crankshaft Nose Bearing

Crankshaft main and rod bearings

Crankshaft main bearings are numbered from the rear of the engine (flywheel end) forward. Main bearing 8, (nose bearing) is at the pulley end.

Crankshaft main bearing shells, if they are to be reused, should only be installed in their original positions.

When servicing crankshaft, bolt crankshaft in special mounting tool (special tool P 209) and mount in a shop vise.

^ Mark installed position of connecting rods and remove them from crankshaft.

Crankshaft journal sizes are listed in Table d. Crankshaft clearance specifications are listed in Table e. Crankshaft bearings are available in standard size and four undersizes.

Crankshaft axial play (also called end play) is controlled by a two-piece thrust bearing. The thrust bearing is the no. 1 main bearing (flywheel end).

Porsche Crankshaft Nose Bearing

0018332

Table d. Crankshaft Journal Sizes

Size (mm)

Main bearing 8 (nose bearing)

Main bearings 1 -7

Connecting rod bearing

Crankshaft drive gear

Crankshaft flywheel

Standard

30.980- 30.993 mm (1.2197-1.2202 in.)

59.971-59.990 mm (2.3611-2.3618 in.)

54.971-54.990 mm (2.1642-2.1650 in.)

42.002-42.013 mm (1.6536-1.6541 in.)

89.780-90.000 mm (3.5346-3.5433 in.)

Undersize 1 (- 0.25 mm)

30.730 - 30.743 mm (1.2098-1.2103 in.)

59.721-59.740 mm (2.3512- 2.3520 in.)

54.721 - 54.740 mm (2.1544 - 2.1551 in.)

Undersize 2 (- 0.50 mm)

30.480 - 30.493 mm (1.2000-1.2005 in.)

59.471- 59.490 mm (2.3414-2.3421 in.)

54.471 - 54.490 mm (2.1445 - 2.1453 in.)

Undersize 3 (- 0.75 mm)

30.230 - 30.243 mm (1.1901 -1.1907 in.)

59.221 - 59.240 mm (2.3315-2.3323 in.)

54.221 - 54.240 mm (2.1347 - 2.1354 in.)

Undersize 4 (-1.00 mm)

29.980 - 29.993 mm (1.1803-1.1808 in.)

58.971 - 58.990 mm 2.3217 - 2.3224 in.)

53.971 - 53.990 mm (2.1248 - 2.1256 in.)

-

-

Axial play should be measured at the center main bearing journal with the crankshaft supported on rollers on the outer main bearing journals.

Table e. Crankshaft Clearances

Crankshaft main bearing no. 1-7 radial clearance (Plastigage®)

0.010-0.072 mm (0.0003-0.0028 in.)

Crankshaft main bearing no. 8 radial clearance (Plastigage®)

0.048-0.104 mm (0.0019-0.0041 in.)

Connecting rod bearing radial clearance (Plastigage®)

0.020-0.088 mm (0.0008-0.0035 in.)

Crankshaft axial clearance Wear limit

0.110-0.195 mm (0.0043-0.0078 in.) 0.20 mm (0.008 in.)

Maximum permissible crankshaft runout

0.15 mm (0.0060 in.)

Connecting rods

— Check weight of each connecting rod. Weigh a complete connecting rod, less the bearing shells. See Table f.

Replacement connecting rods are available in different weight classes. Each class can be identified by the last digit of the part number. The weight class is stamped on the shaft of the connecting rod.

CAUTION—

In a complete set of connecting rods installed in one engine no two must differ in weight by more than 9 grams.

— Hold connecting rod in soft-jawed vise and torque old rod bolts/nuts for measurement.

Do not use new fasteners when making this check. This check should be performed with used rod bolts.

Porsche Rod Bolts Pics

Checking Torque

• Connecting rod bolt/nut 50-55 Nm (37-41 ft-lb)

^ Use micrometer and bore gauge to check connecting rod dimensions. See Table g.

Table f. Connecting Rod Weights

Weight in grams

Weight class

Porsche P/N

615 to 624

3

964 103 020 53

624 to 633

4

964 103 020 54

633 to 642

5

964 103 020 55

642 to 651

6

964 103 020 56

651 to 660

7

964 103 020 57

660 to 669

8

964 103 020 58

669 to 678

9

964 103 020 59

678 to 687

10

964 103 020 60

687 to 696

11

964 103 020 61

Table g. Connecting Rod Dimensions

Big end bore (A)

58.000 - 58.019 mm (2.2835-2.2842 in.)

Small end bore (B)

23.020 - 23.033 mm

Width at big end (C)

1984-1985

1986-1989

21.70 - 21.80 mm (0.8543 - 0.8583 in.) 21.85 - 21.90 mm (0.8602 - 0.8622 in.)

Width at small end (D)

24.5 - 25.0 mm (0.9646 - 0.9842 in.)

Distance between centers (E)

126.95 -127.00 mm (4.998 - 5.000 in.)

Connecting rod bushing/piston pin clearance Wear limit

0.020 - 0.037 mm (0.0008 - 0.0014 in.) 0.055 mm (0.0022 in.)

— Check piston pin fit to small end bushing. Pin should slide through bushing with light pressure.

— Check that numbers stamped on side of cap and rod are the same (cap and rod are a matched set).

— Insert bearing shells in connecting rod and corresponding rod cap.

— Lubricate bearing surfaces with suitable engine assembling lubricant.

Porsche 911 Con Rod Assembly

Always use new connecting rod nuts and bolts during final assembly.

^ During reinstallation, matching numbers on side of connecting rod and rod cap should all be facing same side of engine (for example, all marked numbers should face exhaust side of engine).

^ With all connecting rods installed, torque each connecting rod nut.

Tightening Torques

• Connecting rod bolt/nut

Connecting rod must rotate easily under its own weight when the bearing is lubricated with engine oil.

440 Exhaust Bolts And Nuts Diagram
...0018073d

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