Peugeot 405 Manual

Crankshaft - refitting and main bearing running clearance check
Engine removal and overhaul procedures / Crankshaft - refitting and main bearing running clearance check


Selection of new bearing shells TU series engine
1 On early engines, both upper and lower main bearing shells were of the same thickness, with only two sizes of bearing shells being available: a standard size for use with the standard crankshaft, and a set of oversize bearing shells for use once the crankshaft bearing journals have been reground.

2 However, since February 1992, the specified main bearing running clearance has been significantly reduced. This has been achieved by the introduction of three different grades of bearing shell, in both standard sizes and oversizes. The grades are indicated by a colour-coding marked on the edge of each shell, which denotes the shells thickness, as listed in the following table. The upper shell on all bearings is of the same size (class B, colour code black), and the running clearance is controlled by fitting a lower bearing shell of the required thickness. This arrangement has been fitted to all engines produced since February 1992 and, if possible, should also be fitted to earlier engines during overhaul. Seek the advice of your Peugeot dealer on parts availability and the best course of action when ordering new bearing shells.

Aluminium block engine
Bearing Thickness (mm)
colour code Standard Undersize Blue (class A) 1.823 1.973 Black (class B) 1.835 1.985 Green (class C) 1.848 1.998 Cast-iron block engine
Bearing Thickness (mm)
colour code Standard Undersize Blue (class A) 1.844 1.994 Black (class B) 1.858 2.008 Green (class C) 1.869 2.019 3 On early engines, the correct size of bearing shell must be selected by measuring the running clearance as described under the sub-heading below.

4 On engines produced since February 1992, when the new bearing shell sizes were introduced, the crankshaft and cylinder block/crankcase have reference marks on them, to identify the size of the journals and bearing bores.

5 The cylinder block reference marks are on the right-hand (timing belt) end of the block, and the crankshaft reference marks are on the right-hand (timing belt) end of the crankshaft, on the right-hand web of No 4 crankpin (see illustration). These marks can be used to select bearing shells of the required thickness as follows.

18.5 Cylinder block and crankshaft main bearing reference marking locations -
18.5 Cylinder block and crankshaft main bearing reference marking locations - TU series engines

6 On both the crankshaft and block there are two lines of identification: a bar code, which is used by Peugeot during production, and a row of five letters. The first letter in the sequence refers to the size of No 1 bearing (at the flywheel/driveplate end). The last letter in the sequence (which is followed by an arrow) refers to the size of No 5 main bearing. These marks can be used to select the required bearing shell grade as follows.

7 Obtain the identification letter of both the relevant crankshaft journal and the cylinder block bearing bore. Noting that the cylinder block letters are listed across the top of the chart, and the crankshaft letters down the side, trace a vertical line down from the relevant cylinder block letter, and a horizontal line across from the relevant crankshaft letter, and find the point at which both lines cross.

This crossover point will indicate the grade of lower bearing shell required to give the correct main bearing running clearance. For example, the illustration shows cylinder block reference G, and crankshaft reference T, crossing at a point within the area of Class A, indicating that a blue-coded (Class A) lower bearing shell is required to give the correct main bearing running clearance (see illustration).

18.7 Main bearing shell selection chart, for use with TU series engines - see
18.7 Main bearing shell selection chart, for use with TU series engines - see text for further information

8 Repeat this procedure so that the required bearing shell grade is obtained for each of the five main bearing journals.

XU series engine
9 On some early engines, both the upper and lower bearing shells were of the same thickness.

10 However, on later engines the main bearing running clearance was significantly reduced. To enable this to be done, four different grades of bearing shell were introduced. The grades are indicated by a colour-coding marked on the edge of each shell, which denotes the shells thickness, as listed in the following table. The upper shell on all bearings is of the same size, and the running clearance is controlled by fitting a lower bearing shell of the required thickness.

Note: On all XU series engines, upper shells are easily distinguished from lower shells, by their grooved bearing surface; the lower shells have a plain surface. It was not clear at the time of writing whether undersize bearing shells are available for 1998 cc engine. Refer to your Peugeot dealer for the latest information.

1580 cc, 1761 cc and 1905 cc engines Bearing colour Thickness (mm) code Standard Undersize
Upper bearing:
Yellow 1.856 2.006
Lower bearing:
Blue (Class A) 1.836 1.986 Black (Class B) 1.848 1.998 Green (Class C) 1.859 2.009 Red (Class D) 1.870 2.020 1998 cc engines
Bearing colour Thickness (mm) code Standard Undersize
Upper bearing:
Black 1.847 N/A
Lower bearing:
Blue (Class A) 1.844 N/A Black (Class B) 1.857 N/A Green (Class C) 1.866 N/A Red (Class D) 1.877 N/A
11 On most later engines, new bearing shells can be selected using the reference marks on the cylinder block/crankcase. The cylinder block marks identify the diameter of the bearing bores, and the crankshaft marks the diameter of the crankshaft journals. Where no marks are present, the bearing shells can only be selected by checking the running clearance (see below).

12 The cylinder block reference marks are on the left-hand (flywheel/driveplate) end of the block, and the crankshaft reference marks are on the end web of the crankshaft (see illustration). These marks can be used to select bearing shells of the required thickness as follows.

18.12 Cylinder block and crankshaft main bearing reference marking locations
18.12 Cylinder block and crankshaft main bearing reference marking locations - XU series engines

A Bar Code (for production use only) B Reference marks

13 On both the crankshaft and block there are two lines of identification: a bar code, which is used by Peugeot during production, and a row of five letters. The first letter in the sequence refers to the size of No 1 bearing (at the flywheel/driveplate end). The last letter in the sequence (which is followed by an arrow) refers to the size of No 5 main bearing. These marks can be used to select the required bearing shell grade as follows.

14 Obtain the identification number/letter of both the relevant crankshaft journal and the cylinder block bearing bore. Noting that the crankshaft references are listed across the top of the chart, and the cylinder block references down the side, trace a vertical line down from the relevant crankshaft reference, and a horizontal line across from the relevant cylinder block reference, and find the point at which both lines cross. This crossover point will indicate the grade of lower bearing shell required to give the correct main bearing running clearance. For example, the illustration shows crankshaft reference 6, and cylinder block reference H, crossing at a point within the RED area, indicating that a Redcoded (Class D) lower bearing shell is required to give the correct main bearing running clearance (see illustration).

18.14 Main bearing shell selection chart, for use with XU series engines -
18.14 Main bearing shell selection chart, for use with XU series engines - see text for further information

15 Repeat this procedure so that the required bearing shell grade is obtained for each of the five main bearing journals.

16 Seek the advice of your Peugeot dealer on parts availability, and on the best course of action when ordering new bearing shells.

Note: On early models, at overhaul it is recommended that the later bearing shell arrangement is fitted. This, however, should only be done if the lubrication system components are upgraded (necessitating replacement of the oil pump relief valve piston and spring as well as the pump sprocket and drive chain) at the same time. If the new bearing arrangement is to be used without uprating the lubrication system, Peugeot state that Blue (Class A) lower bearing shells should be fitted. Refer to your Peugeot dealer for further information.

17 Since there are no bearing identification marks, the relevant main bearing shell grade must be selected by measuring the main bearing running clearance.

Main bearing
running clearance check
TU series engine
18 On early engines, if the modified bearing shells are to be fitted, obtain a set of new black (Class B) upper bearing shells and new blue (Class A) lower bearing shells. On later (February 1992-on) engines where the modified bearing shells are already fitted, the running clearance check can be carried out using the original bearing shells. However, it is preferable to use a new set, since the results obtained will be more conclusive.

19 Clean the backs of the bearing shells, and the bearing locations in both the cylinder block/crankcase and the main bearing ladder.

20 Press the bearing shells into their locations, ensuring that the tab on each shell engages in the notch in the cylinder block/crankcase or main bearing ladder location. Take care not to touch any shells bearing surface with your fingers. Note that the grooved bearing shells, both upper and lower, are fitted to Nos 2 and 4 main bearings (see illustration). If the original bearing shells are being used for the check, ensure that they are refitted in their original locations. The clearance can be checked in either of two ways.

18.20 On TU series engines, note that the grooved bearing shells are fitted
18.20 On TU series engines, note that the grooved bearing shells are fitted to Nos 2 and 4 main bearing journals

21 One method (which will be difficult to achieve without a range of internal micrometers or internal/external expanding calipers) is to refit the main bearing ladder casting to the cylinder block/crankcase, with the bearing shells in place. With the casting retaining bolts correctly tightened, measure the internal diameter of each assembled pair of bearing shells. If the diameter of each corresponding crankshaft journal is measured and then subtracted from the bearing internal diameter, the result will be the main bearing running clearance.

22 The second (and more accurate) method is to use a product known as Plastigauge.

This consists of a fine thread of perfectlyround plastic, which is compressed between the bearing shell and the journal. When the shell is removed, the plastic is deformed, and can be measured with a special card gauge supplied with the kit. The running clearance is determined from this gauge. Plastigauge should be available from your Peugeot dealer, otherwise enquiries at one of the larger specialist motor factors should produce the name of a stockist in your area. The procedure for using Plastigauge is as follows.

23 With the main bearing upper shells in place, carefully lay the crankshaft in position.

Do not use any lubricant; the crankshaft journals and bearing shells must be perfectly clean and dry.

24 Cut several lengths of the appropriatesize Plastigauge (they should be slightly shorter than the width of the main bearings), and place one length on each crankshaft journal axis (see illustration).

18.24 Plastigauge in place on a crankshaft main bearing journal
18.24 Plastigauge in place on a crankshaft main bearing journal

25 With the main bearing lower shells in position, refit the main bearing ladder casting, tightening its retaining bolts as described in paragraph 45. Take care not to disturb the Plastigauge, and do not rotate the crankshaft at any time during this operation.

26 Remove the main bearing ladder casting, again taking great care not to disturb the Plastigauge or rotate the crankshaft.

27 Compare the width of the crushed Plastigauge on each journal to the scale printed on the Plastigauge envelope, to obtain the main bearing running clearance (see illustration). Compare the clearance measured with that given in the Specifications at the start of this Chapter.

18.27 Measuring the width of the deformed Plastigauge using the scale on the
18.27 Measuring the width of the deformed Plastigauge using the scale on the card provided

28 If the clearance is significantly different from that expected, the bearing shells may be the wrong size (or excessively worn, if the original shells are being re-used). Before deciding that different-size shells are required, make sure that no dirt or oil was trapped between the bearing shells and the caps or block when the clearance was measured. If the Plastigauge was wider at one end than at the other, the crankshaft journal may be tapered.

29 If the clearance is not as specified, use the reading obtained, along with the shell thicknesses quoted above, to calculate the necessary grade of bearing shells required.

When calculating the bearing clearance required, bear in mind that it is always better to have the running clearance towards the lower end of the specified range, to allow for wear in use.

30 Where necessary, obtain the required grades of bearing shell, and repeat the running clearance checking procedure as described above.

31 On completion, carefully scrape away all traces of the Plastigauge material from the crankshaft and bearing shells. Use your fingernail, or a wooden or plastic scraper which is unlikely to score the bearing surfaces.

XU series engine
32 On early engines, if the later bearing shells are to be fitted, obtain a set of new upper bearing shells, and new green or grey (as applicable) lower bearing shells (see paragraph 10). On later engines where the modified bearing shells are already fitted, the running clearance check can be carried out using the original bearing shells. However, it is preferable to use a new set, since the results obtained will be more conclusive.

33 Clean the backs of the bearing shells, and the bearing locations in both the cylinder block/crankcase and the main bearing caps.

34 Press the bearing shells into their locations, ensuring that the tab on each shell engages in the notch in the cylinder block/crankcase or bearing cap. Take care not to touch any shells bearing surface with your fingers. Note that the upper bearing shells all have a grooved bearing surface, whereas the lower shells have a plain bearing surface (see illustration). If the original bearing shells are being used for the check, ensure that they are refitted in their original locations.

18.34 On XU engines, all the lower shells have a plain bearing surface.
18.34 On XU engines, all the lower shells have a plain bearing surface. Ensure tab (arrowed) is correctly located in the cap

35 The clearance can be checked in two ways.

36 One method (which will be difficult to achieve without a range of internal micrometers or internal/external expanding calipers) is to refit the main bearing caps to the cylinder block/crankcase, with bearing shells in place. With the cap retaining bolts tightened to the specified torque, measure the internal diameter of each assembled pair of bearing shells. If the diameter of each corresponding crankshaft journal is measured and then subtracted from the bearing internal diameter, the result will be the main bearing running clearance.

37 The second, and more accurate, method is to use Plastigauge. The method is as described above in paragraphs 17 to 26, substituting main bearing caps for all references to the main bearing ladder casting.

38 Note that Peugeot do not specify a main bearing running clearance for 1905 cc engines. The figure given in the Specifications is a guide figure which is typical for this type of engine. On these engines, therefore, always refer to your Peugeot dealer for details of the exact running clearance before condemning the components concerned.

Final crankshaft refitting TU aluminium block engines 39 Carefully lift the crankshaft out of the cylinder block once more.

40 Using a little grease, stick the upper thrustwashers to each side of the No 2 main bearing upper location; ensure that the oilway grooves on each thrustwasher face outwards (away from the cylinder block) (see illustration).

18.40 Refitting a crankshaft thrustwasher - TU series aluminium block engine
18.40 Refitting a crankshaft thrustwasher - TU series aluminium block engine

41 Place the bearing shells in their locations as described earlier. If new shells are being fitted, ensure that all traces of protective grease are cleaned off using paraffin. Wipe dry the shells and connecting rods with a lintfree cloth. Liberally lubricate each bearing shell in the cylinder block/crankcase with clean engine oil (see illustration).

18.41 Ensure each bearing shell tab (arrowed) is correctly located, and apply
18.41 Ensure each bearing shell tab (arrowed) is correctly located, and apply clean engine oil

42 Refit the Woodruff key, then slide on the oil pump drive sprocket, and locate the drive chain on the sprocket (see illustration).

18.42 Refitting the oil pump drive chain and sprocket - TU aluminium block
18.42 Refitting the oil pump drive chain and sprocket - TU aluminium block engine

Lower the crankshaft into position so that Nos 2 and 3 cylinder crankpins are at TDC; Nos 1 and 4 cylinder crankpins will be at BDC, ready for fitting No 1 piston. Check the crankshaft endfloat as described in Section 13.

43 Thoroughly degrease the mating surfaces of the cylinder block/crankcase and the main bearing ladder. Apply a thin bead of suitable sealant to the cylinder block/crankcase mating surface of the main bearing ladder casting, then spread to an even film (see illustration).

18.43 Apply a film of suitable sealant to cylinder block/crankcase mating
18.43 Apply a film of suitable sealant to cylinder block/crankcase mating surface . . .

44 Lubricate the lower bearing shells with clean engine oil, then refit the main bearing ladder, ensuring that the shells are not displaced, and that the locating dowels engage correctly (see illustration).

18.44 . . . then lower the main bearing ladder into position
18.44 . . . then lower the main bearing ladder into position

45 Install the ten 11 mm main bearing ladder retaining bolts, and tighten them all by hand only. Working progressively outwards from the centre bolts, tighten the ten bolts, by a turn at a time, to the specified Stage 1 torque wrench setting. Once all the bolts have been tightened to the Stage 1 setting, angle-tighten the bolts through the specified Stage 2 angle using a socket and extension bar. It is recommended that an angle-measuring gauge is used during this stage of the tightening, to ensure accuracy (see illustrations).

18.45a Tighten ten 11 mm main bearing bolts to the stage 1 torque setting . .
18.45a Tighten ten 11 mm main bearing bolts to the stage 1 torque setting . . .

18.45b . . . then angle-tighten them through the specified stage 2 angle
18.45b . . . then angle-tighten them through the specified stage 2 angle

If a gauge is not available, use a dab of white paint to make alignment marks between the bolt head and casting prior to tightening; the marks can then be used to check that the bolt has been rotated sufficiently during tightening.

46 Refit all the 6 mm bolts securing the main bearing ladder to the base of the cylinder block, and tighten them to the specified torque. Check that the crankshaft rotates freely.

47 Refit the piston/connecting rod assemblies to the crankshaft as described in Section 18.

48 Ensuring that the drive chain is correctly located on the sprocket, refit the oil pump and sump as described in Part A of this Chapter.

49 Fit two new crankshaft oil seals as described in Part A.

50 Refit the flywheel as described in Part A of this Chapter.

51 Where removed, refit the cylinder head as described in Part A. Also refit the crankshaft sprocket and timing belt as described in Part A.

TU series cast-iron block engine 52 Carefully lift the crankshaft out of the cylinder block once more.

53 Using a little grease, stick the upper thrustwashers to each side of No 2 main bearing upper location. Ensure the oilway grooves on each thrustwasher face outwards (away from the cylinder block) (see illustration).

18.53 Fitting a thrustwasher to No 2 main bearing upper location
18.53 Fitting a thrustwasher to No 2 main bearing upper location

54 Place the bearing shells in their locations as described earlier (see illustration). If new shells are being fitted, ensure that all traces of protective grease are cleaned off using paraffin. Wipe dry the shells and connecting rods with a lint-free cloth. Liberally lubricate each bearing shell in the cylinder block/ crankcase and cap with clean engine oil.

18.54 Ensure tab (arrowed) is located in the cap when fitting the bearing
18.54 Ensure tab (arrowed) is located in the cap when fitting the bearing shells

55 Lower the crankshaft into position so that Nos 2 and 3 cylinder crankpins are at TDC; Nos 1 and 4 cylinder crankpins will be at BDC, ready for fitting No 1 piston. Check the crankshaft endfloat, referring to Section 14.

56 Lubricate the lower bearing shells in the main bearing caps with clean engine oil. Make sure that the locating lugs on the shells engage with the corresponding recesses in the caps.

57 Fit the main bearing caps to their correct locations, ensuring that they are fitted the correct way round (the bearing shell lug recesses in the block and caps must be on the same side). Insert the bolts loosely.

58 Tighten the main bearing cap bolts to the specified Stage 1 torque wrench setting.

Once all the bolts have been tightened to the Stage 1 setting, angle-tighten the bolts through the specified Stage 2 angle, using a socket and extension bar. It is recommended that an angle-measuring gauge is used during this stage of the tightening, to ensure accuracy. If a gauge is not available, use a dab of white paint to make alignment marks between the bolt head and casting prior to tightening; the marks can then be used to check that the bolt has been rotated sufficiently during tightening.

59 Check that the crankshaft rotates freely.

60 Refit the piston/connecting rod assemblies to the crankshaft as described in Section 19.

61 Refit the Woodruff key to the crankshaft groove, and slide on the oil pump drive sprocket. Locate the drive chain on the sprocket.

62 Ensure that the mating surfaces of front oil seal housing and cylinder block are clean and dry. Note the correct fitted depth of the front oil seal then, using a large flat-bladed screwdriver, lever the seal out of the housing.

63 Apply a smear of suitable sealant to the oil seal housing mating surface, and make sure that the locating dowels are in position. Slide the housing over the end of the crankshaft, and into position on the cylinder block.

Tighten the housing retaining bolts securely.

64 Repeat the operations in paragraphs 62 and 63, and fit the rear oil seal housing.

65 Fit a new front and rear crankshaft oil seal as described in Part A of this Chapter.

66 Ensuring that the chain is correctly located on the drive sprocket, refit the oil pump and sump as described in Part A of this Chapter.

67 Refit the flywheel (Part A of this Chapter).

68 Where removed, refit the cylinder head and install the crankshaft sprocket and timing belt - see the relevant Sections of Part A.

XU series engines
69 Carry out the operations described above in paragraphs 52 to 56.

70 Fit main bearing caps Nos 2 to 5 to their correct locations, ensuring that they are fitted the correct way round (the bearing shell tab recesses in the block and caps must be on the same side). Insert the bolts/nuts, tightening them only loosely at this stage.

71 Apply a small amount of sealant to No 1 main bearing cap face mating on the cylinder block, around the sealing strip holes (see illustration).

18.71 Applying sealant to the cylinder block No 1 main bearing cap mating
18.71 Applying sealant to the cylinder block No 1 main bearing cap mating face

72 Locate the tab of each sealing strip over the pins on the base of No 1 bearing cap, and press the strips into the bearing cap grooves.

It is now necessary to obtain two thin metal strips, of 0.25 mm thickness or less, in order to prevent the strips moving when the cap is being fitted. Peugeot garages use the tool shown, which acts as a clamp. Metal strips (such as old feeler blades) can be used, provided all burrs which may damage the sealing strips are first removed (see illustrations).

18.72a Fitting a sealing strip to No 1 main bearing cap
18.72a Fitting a sealing strip to No 1 main bearing cap

18.72b Using the Peugeot special tool to fit No 1 main bearing cap
18.72b Using the Peugeot special tool to fit No 1 main bearing cap

73 Where applicable, oil both sides of the metal strips, and hold them on the sealing strips. Fit the No 1 main bearing cap, insert the bolts loosely, then carefully pull out the metal strips in a horizontal direction, using a pair of pliers (see illustrations).

18.73a Fitting No 1 main bearing cap, using metal strips to retain the side
18.73a Fitting No 1 main bearing cap, using metal strips to retain the side seals

18.73b Removing a metal strip from No 1 main bearing cap using a pair of
18.73b Removing a metal strip from No 1 main bearing cap using a pair of pliers

74 Tighten all the main bearing cap bolts/nuts evenly to the specified torque.

Using a sharp knife, trim off the ends of the No 1 bearing cap sealing strips, so that they protrude above the cylinder block/crankcase mating surface by approximately 1 mm (see illustrations).

18.74a With all bearing caps correctly installed, tighten their retaining
18.74a With all bearing caps correctly installed, tighten their retaining nuts and bolts to the specified torque . . .

18.74b . . . then trim the sealing strips, so that they protrude above the
18.74b . . . then trim the sealing strips, so that they protrude above the cylinder block mating surface by approximately 1 mm

75 On 1580 cc, 1761 cc and 1905 cc engines, refit the centre main bearing side retaining bolts and sealing washers (one at the front of the block, and one at the rear) and tighten them both to the specified torque.

76 Fit a new crankshaft rear oil seal as described in Part B of this Chapter.

77 Refit the piston/connecting rod assemblies to the crankshaft as described in Section 19.

78 Refit the Woodruff key, then slide on the oil pump drive sprocket and spacer (where fitted), and locate the drive chain on the sprocket.

79 Ensure that the mating surfaces of the front oil seal carrier and cylinder block are clean and dry. Note the correct fitted depth of the oil seal then, using a large flat-bladed screwdriver, lever the old seal out of the housing.

80 Apply a smear of suitable sealant to the oil seal carrier mating surface. Ensure that the locating dowels are in position, then slide the carrier over the end of the crankshaft and into position on the cylinder block. Tighten the carrier retaining bolts to the specified torque.

81 Fit a new crankshaft front oil seal as described in Part B of this Chapter.

82 Ensuring that the drive chain is correctly located on the sprocket, refit the oil pump and sump -refer to Part B or C of this Chapter.

83 Where removed, refit the rear timing cover and cylinder head as described in Part B.


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