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Engine

Crankshaft, balancer shafts and piston rings (Turbo)

The factory steps for the Turbo's crankshaft, its bearing clearance checks, oil seals, pulley and sprocket, the balancer shaft unit and its backlash, the piston rings, the crankshaft pulse sensor and the engine vent flange, from the Vauxhall TIS.

vx220.info/guides/crankshaft-balancer-shafts-and-piston-rings-turbo · Last updated 25 October 2026

Applies to: VX220 and Speedster, TurboDifficulty: SpecialistTime: Not stated

Tools

  • KM-535
  • KM-635
  • KM-652
  • KM-662-C
  • KM-693
  • KM-798
  • KM-853
  • KM-949

Torques & specs

Crankshaft bearing caps to cylinder block 50 Nm + 45° + 15°50 Nm
Con-rod bearing caps to con-rod 35 Nm + 45° + 15°35 Nm
Attach transmission to cylinder block – tightening torque 60 Nm60 Nm
Attach crankshaft bearing cap to cylinder block with new bolts - 50 Nm + 45° + 15°.50 Nm
Install con-rod bearing cap with con-rod bearing shell to con-rod - Tightening torque 35 Nm + 45° + 15°.35 Nm
Secure flywheel to crankshaft65 Nm
Install clutch plate with pressure plate to flywheel15 Nm
Install transmission to engine60 Nm
Install transmission to engine40 Nm
Secure 6x bolt 65 Nm + 30° + 15° symmetrically65 Nm
Install 6x new bolt 15 Nm symmetrically15 Nm
Install 7x bolt 60 Nm symmetrically Note: Includes installation of support bracket for engine harness.60 Nm
Install 4x bolt 40 Nm symmetrically40 Nm
Install crankshaft sprocket to crankshaft130 Nm
Install lower cover of camshaft timing belt6 Nm
Install ribbed V-belt tensioner25 Nm
Install crankshaft pulley20 Nm
Install upper cover of camshaft timing belt6 Nm
Secure rear road wheel90 Nm
Install bolt 130 Nm + 45° – Counter-hold using KM-662-C130 Nm
Install 2x bolt 6 Nm6 Nm
Install 2x bolt 25 Nm25 Nm
Install 4x bolt 20 Nm – Counter-hold centre nut on crankshaft sprocket using spanner20 Nm
4x bolt, security bolt 90 Nm90 Nm
Install new crankshaft pulley Note: Note position of crankshaft pulley.20 Nm
Install 4x bolt 20 Nm – Counter-hold centre nut on crankshaft sprocket20 Nm
Install new crankshaft sprocket to crankshaft130 Nm
Secure tensioner20 Nm
Install crankshaft pulley Note: Note position of crankshaft pulley.20 Nm
Secure rear road wheel right side90 Nm
Install new bolt 130 Nm + 45° – Counter-hold using KM-662-C130 Nm
Secure bolt 20 Nm20 Nm
Install crankshaft pulse sensor to engine cylinder block8 Nm
Install accessory bracket to engine cylinder block35 Nm
Install ribbed V-belt idler pulley to accessory bracket20 Nm
Install bolt 8 Nm8 Nm
Install 4x bolt 35 Nm35 Nm
Install 3x bolt, washer 20 Nm20 Nm
Install balancer shaft unit to engine20 Nm
Install oil pick up pipe to engine8 Nm
Install upper oil pan to engine20 Nm
Secure oil level sensor to lower oil pan8 Nm
Install lower oil pan to upper oil pan8 Nm
Install drain bolt 10 Nm10 Nm
Secure rear engine mount46 Nm
Install toothed belt lower cover6 Nm
Install toothed belt upper cover6 Nm
Install 15x bolt 20 Nm + 45°20 Nm
Install 2x bolt to oil pump 8 Nm8 Nm
Secure 2x bolt 46 Nm46 Nm
Install front baffle plate to balancer shaft unit8 Nm
Install 15x bolt 20 Nm + 45° – Clean all mating surfaces20 Nm
Install 2x bolt 8 Nm8 Nm
Install new engine vent flange to engine cylinder block25 Nm
The steps below are shortened from the Vauxhall TIS pages for the Speedster. The VX220 shares the same engines and most of the car, but check anything unusual against your own car. The TIS pictures and the full wording aren't reproduced, so use the workshop manual if you are doing the job. We haven't seen owners' accounts of this job, so there are no owner tips here.

Engine-out work. Clearances are on Turbo engine data and torques on Torque values.

A four post hoist must be used to raise the vehicle when removing the engine undertray and exhaust pipe undertray. The vehicle can be moved to a two post hoist for other operations if required.

Crankshaft: replacement

Turbo (Z20LET) only.

Remove

  1. Attach engine with Adapter KM-412-8-A to Engine Overhaul Stand KM-412 – remove necessary attaching parts.
  2. Remove transmission from cylinder block.
  3. Remove oil pump – see "Oil Pump, Replace".
  4. Remove upper part of oil pan – see "Oil Pan, Upper, Replace".
  5. Remove balancer shaft unit – see "Balancer Shaft Unit, Replace".
  6. Lock flywheel with KM-652 and remove from crankshaft.
  7. Mark order of con-rod bearing caps – bead points to transmission side.
  8. Remove con-rod bearing cap from con-rod.
  9. Mark the order of the crankshaft bearing caps and remove from cylinder block.
  10. Remove crankshaft from cylinder block.

Clean

  1. Clean all parts.

Inspect

  1. Check crankshaft - see "Crankshaft, Out-of-round, Check".

Install

  1. When replacing crankshaft: transfer crankshaft pulse pickup sensor disc with new bolts - tightening torque 13 Nm
  2. Coat new bearing shells with engine oil and insert in cylinder block and bearing caps. Carefully insert crankshaft in cylinder block. The seating of the crankshaft can be corrected by light blows on the crank webs with a rubber hammer. Apply bead of adhesive sealing compound (black) to grooves of the crankshaft rear main bearing cap. Install crankshaft and con-rod bearing caps - note identification.
  3. Crankshaft bearing caps to cylinder block 50 Nm + 45° + 15°
  4. Important: Use new fastening bolts.
  5. Note: After assembly of rear main bearing cap, press in adhesive sealing compound (black) from above again until it escapes from the joints.
  6. Con-rod bearing caps to con-rod 35 Nm + 45° + 15°
  7. Important: Use new fastening bolts.
  8. Install rear crankshaft oil seal – see "Crankshaft Oil Seal, Flywheel Side, Replace".
  9. Install balancer shaft unit – see "Balancer Shaft Unit, Replace".
  10. Install upper part of oil pan – see "Oil Pan, Upper, Replace".
  11. Install oil pump – see "Oil Pump, Replace".
  12. Attach transmission to cylinder block – tightening torque 60 Nm

Crankshaft bearing clearance: micrometer method

Turbo (Z20LET) only.

Remove

  1. Note: The crankshaft is removed.
  2. Install crankshaft bearing cap with crankshaft bearing shell at cylinder block - tightening torque 50 Nm + 45° + 15°. To check the crankshaft bearing play, bolt can be reused.

Measure

  1. The average crankshaft bearing diameter is determined using an inside micrometer at points I, II and III and then calculated.
  2. Formula for calculating the average crankshaft bearing diameter:
  3. I + II + III
  4. Example:
  5. 54.972 mm
  6. 54.981 mm
  7. + 54.984 mm
  8. 164.937 mm
  9. ÷ 3 = 54.979 mm
  10. The average crankshaft bearing diameter is 54.979 mm.
  11. The crankshaft journal diameter is measured with a micrometer at points I and II and then calculated.
  12. Formula for calculating the average crankshaft bearing journal diameter:
  13. I + II
  14. Example:
  15. 54.962 mm
  16. + 54.964 mm
  17. 109.926 mm
  18. ÷ 2 = 54.963 mm
  19. The average crankshaft journal diameter is 54.963 mm.
  20. The crankshaft play is calculated from the difference in diameter between the crankshaft bearing bore and crankshaft journal.
  21. Example:
  22. Average crankshaft bearing diameter
  23. 54.979 mm
  24. Average crankshaft journal diameter
  25. - 54.963 mm
  26. 0.016 mm
  27. Permissible crankshaft bearing play: 0.015 to 0.043 mm.

Crankshaft bearing clearance: Plastigage method

Turbo (Z20LET) only.

Inspect

  1. Bearing play - bearing cover removed.
  2. Caution
  3. Clean crankshaft journal and crankshaft bearing shell and lubricate slightly so that thread does not tear when bearing cap is removed. Do not turn crankshaft.

Measure

  1. With "Plastigage" (deformable plastic thread).
  2. Cut strip to width of bearing and lay axially between crankshaft bearing journal and bearing shell (arrow). Attach bearing cap with torque - tightening torque 50 Nm + 45° + 15°.
  3. Note: The bolts can be reused for checking crankshaft bearing play.
  4. Compare width of flattened plastic thread (arrow) with measuring scale.
  5. "Plastigage" is available for various measuring ranges.
  6. Perm. crankshaft bearing play: 0.015 to 0.043 mm.
  7. Note: When reading the value, do not confuse millimetres with inches on the measuring scale.
  8. Torque-angle method
  9. Attach crankshaft bearing cap to cylinder block with new bolts - 50 Nm + 45° + 15°.

Remove

  1. Remove bearing cover.

Con-rod bearing play: micrometer method

Turbo (Z20LET) only.

Install

  1. Note: Con-rod and crankshaft are removed.
  2. Install con-rod bearing cap with con-rod bearing shell to con-rod - Tightening torque 35 Nm + 45° + 15°.
  3. The bolts can be reused for checking the con-rod bearing play.

Measure

  1. Formula for calculating the average con-rod bearing diameter:
  2. I + II + III
  3. Example:
  4. 42.738 mm
  5. 42.732 mm
  6. + 42.741 mm
  7. 128.211 mm
  8. ÷ 3 = 42.737 mm
  9. The average con-rod bearing diameter is 42.737 mm.
  10. The con-rod bearing journal diameter is measured with a micrometer at points I and II and then calculated.
  11. Formula for calculating the average con-rod bearing journal diameter:
  12. I + II
  13. Example:
  14. 42.729 mm
  15. + 42.725 mm
  16. 85.454 mm
  17. ÷ 2 = 42.727 mm
  18. The average con-rod bearing journal diameter is 42.727 mm. The con-rod bearing play is calculated from the difference in diameter between the con-rod bearing bore and the con-rod bearing journal.
  19. Example:
  20. Average con-rod bearing diameter
  21. 42.737 mm
  22. Average con-rod bearing journal diameter
  23. - 42.727 mm
  24. 0.010 mm
  25. Permissible con-rod bearing play: 0.006 to 0.031 mm.

Con-rod bearing play: Plastigage method

Turbo (Z20LET) only.

Measure

  1. Mark installation position of con-rod bearing cap - remove con-rod bearing cap from con-rod.
  2. Caution
  3. To prevent the strip from tearing when removing the con-rod bearing cap, remove grease from the con-rod journal and lightly oil con-rod bearing shell. Do not turn the crankshaft.
  4. Route Plastigage (malleable plastic strip) over the entire width of the con-rod bearing journal.
  5. Torque-angle method
  6. Attach con-rod bearing cap to con-rod - tightening torque 35 Nm + 45° + 15. To check the con-rod bearing play, the bolts can be used once again.
  7. Remove con-rod bearing cap again. Compare width of flattened plastic thread (arrow) with measuring scale.
  8. Permissible con-rod bearing play: 0.006 to 0.031 mm.
  9. Note: When reading the value, do not confuse millimetres and inches on the measuring scale.

Install

  1. Clean con-rod bearing journal and con-rod bearing shell and lubricate lightly.
  2. Attach con-rod bearing cap to con-rod with new bolts - note installation position of con-rod bearing cap - tightening torque 35 Nm + 45° + 15°.

Crankshaft oil seal, flywheel side

Turbo (Z20LET) only.

Remove

  1. Remove engine with transmission - see “Engine with Transmission, Remove and Install (Z 20 LET)”
  2. Remove turbocharger heat shield from engine and transmission assembly (Remove 2x bolt)
  3. Remove transmission from engine assembly (Remove 11x bolt)
  4. Remove clutch plate with pressure plate from flywheel
    • Install Flywheel Holder KM-652 to (Install Flywheel Holder KM-652 to engine block)
    • Remove 6x bolt, then discard
  5. Remove flywheel from crankshaft (Remove 6x bolt, then discard)
  6. Remove Flywheel Holder KM-652 from engine block
  7. Remove seal ring from crankshaft (Prise out using suitable tool)

Install

  1. Install seal ring to crankshaft (Use Seal Ring Installer KM-635 with; Apply oil to seal lip)
  2. Install flywheel to crankshaft (Do not tighten (Apply locking compound))
  3. Immobilize flywheel (Install Flywheel Holder KM-652 to)
  4. Secure flywheel to crankshaft (Secure 6x bolt 65 Nm + 30° +)
  5. Install clutch plate with pressure plate to flywheel (Install 6x new bolt 15 Nm)
  6. Remove Flywheel Holder KM-652 from engine block
  7. Install transmission to engine (Install 7x bolt 60 Nm; Install 4x bolt 40 Nm)
  8. Install turbocharger heat shield to engine and transmission assembly (Install 2x bolt)
  9. Check oil level and top-up if required

Crankshaft oil seal, timing side

Turbo (Z20LET) only.

Remove

  1. Remove engine undertray (Raise vehicle; Remove 13x bolt, 13x washer)
  2. Lower vehicle
  3. Disconnect battery negative lead
    • Release windscreen wash reservoir, then move to one side
    • Remove nut, bolt
  4. Disconnect intercooler hose from throttle body (Release clip)
  5. Raise vehicle to suitable working height and support
  6. Remove rear road wheel from right side
    • Use special socket located under front bonnet
    • Remove 4x wheel bolt
  7. Remove liner from wheel arch (Remove 6x screw)
  8. Disconnect intercooler hose from intercooler (Release clip; Remove, then discard 4x cable tie)
  9. Remove upper cover of camshaft timing belt (Remove 2x bolt)
  10. Remove ribbed V-belt
    • Using suitable spanner rotate tensioner clockwise, then (Using suitable spanner rotate tensioner clockwise, then Install suitable locking pin)
  11. Remove crankshaft pulley
    • Apply match marks to crankshaft pulley and crankshaft
    • Remove 4x bolt, using spanner to counter-hold centre nut on
  12. Remove ribbed V-belt tensioner (Remove 2x bolt)
  13. Remove lower cover of camshaft timing belt (Remove 2x bolt)
  14. Rotate crankshaft clockwise to top dead centre (TDC) on cylinder No. 1, until 2x timing mark are aligned
  15. Lock camshafts in position (Use Locking Tool KM-853)
  16. Release tension from camshaft timing belt
    • Release bolt, then turn adjusting eccentric in direction of
  17. Remove camshaft timing belt from pulleys, move to one side
    • Do not remove camshaft timing belt from vehicle
  18. Remove crankshaft sprocket from crankshaft (Counter-hold using KM-662-C)
  19. Remove retaining key from crankshaft (Prise out using suitable tool)
  20. Remove washer from crankshaft
  21. Remove, then discard crankshaft oil seal from crankshaft (Prise out using suitable tool)

Install

  1. Install new crankshaft oil seal to crankshaft (Use Assembly Sleeve KM-693)
  2. Install washer to crankshaft
  3. Install retaining key to crankshaft
  4. Install crankshaft sprocket to crankshaft (Counter-hold using KM-662-C)
  5. Install camshaft timing belt to pulleys (Ensure timing marks are aligned)
  6. Adjust tension of camshaft timing belt - see “Camshaft Timing Belt Tension, Check and Adjust (Z 20 LET)”
  7. Install lower cover of camshaft timing belt (Install 2x bolt 6 Nm)
  8. Install ribbed V-belt tensioner (Install 2x bolt 25 Nm)
  9. Install crankshaft pulley
    • Align match marks on crankshaft pulley and crankshaft
    • Counter-hold centre nut on crankshaft sprocket using (Counter-hold centre nut on crankshaft sprocket using spanner)
  10. Install ribbed V-belt
    • Using suitable spanner rotate tensioner clockwise, then remove
  11. Install upper cover of camshaft timing belt (Install 2x bolt 6 Nm)
  12. Install intercooler hose to intercooler (Secure clip; Install 4x new cable tie)
  13. Install liner to wheel arch (Install 6x screw)
  14. Install rear road wheel (Install 4x bolt, security bolt; Do not tighten)
  15. Lower vehicle
  16. Secure rear road wheel (Tighten 4x bolt, security bolt 90)
  17. Connect intercooler hose to throttle body (Secure clip)
  18. Connect battery negative lead (Install nut, bolt; Secure windscreen wash reservoir)
  19. Program all volatile memories
  20. Raise vehicle
  21. Install engine undertray (Install 13x bolt, 13x washer)
  22. Lower vehicle

Crankshaft pulley

Turbo (Z20LET) only.

Remove

  1. Remove engine undertray (Raise vehicle; Remove 13x bolt, 13x washer)
  2. Remove ribbed V-belt
    • Using suitable spanner rotate tensioner clockwise, then (Using suitable spanner rotate tensioner clockwise, then Install suitable locking pin)
  3. Remove crankshaft pulley Note: Note position of crankshaft pulley.
    • Counter-hold centre bolt on crankshaft sprocket

Install

  1. Install new crankshaft pulley Note: Note position of crankshaft pulley.
    • Counter-hold centre nut on crankshaft sprocket
  2. Install ribbed V-belt
    • Use suitable spanner to rotate tensioner clockwise, then remove
  3. Install engine undertray (Install 13x bolt, 13x washer)
  4. Lower vehicle

Crankshaft sprocket (timing belt)

Turbo (Z20LET) only.

Remove

  1. Remove engine undertray (Raise vehicle; Remove 13x bolt, 13x washer)
  2. Lower vehicle
  3. Disconnect battery negative lead
    • Release windscreen wash reservoir, then move to one side
    • Release nut, bolt
  4. Disconnect intercooler hose from connecting pipe for throttle body (Release clip; Pull off)
  5. Raise vehicle to suitable working height
  6. Remove rear road wheel from right side
    • Use special socket located under front bonnet
    • Remove 4x wheel bolt
  7. Remove wheel arch liner, right rear (Remove 4x screw, 2x clip)
  8. Remove intercooler hose from intercooler (Release clip; Remove, then discard 4x cable tie)
  9. Remove upper front cover for timing belt (Remove 2x bolt; Pull off)
  10. Remove ribbed V-belt
    • Using suitable spanner rotate tensioner clockwise, then (Using suitable spanner rotate tensioner clockwise, then Install suitable locking pin)
  11. Remove crankshaft pulley Note: Note position of crankshaft pulley.
    • Counter-hold centre bolt on crankshaft sprocket
  12. Remove ribbed V-belt tensioner (Remove 2x bolt)
  13. Remove lower cover for timing belt (Remove 2x bolt)
  14. Rotate crankshaft in normal direction of rotation to Top Dead Centre (TDC) on cylinder no. 1, until timing marks are aligned
  15. Lock camshafts in position (Use Locking Tool KM-853)
  16. Release tension from timing belt
    • Release bolt, then turn adjusting eccentric clockwise in
  17. Remove timing belt from pulleys (Position timing belt to one side)
  18. Remove crankshaft sprocket from crankshaft (Counter-hold using KM-662-C)

Install

  1. Install new crankshaft sprocket to crankshaft (Counter-hold using KM-662-C)
  2. Check timing marks are aligned
  3. Install timing belt to pulleys
  4. Pre-tension timing belt
    • Turn eccentric of tensioner in direction of arrow
    • Remove Locking Tool KM-853 from
    • Rotate crankshaft two complete turns in normal direction of
    • Install Locking Tool KM-853 to
  5. Tension timing belt
    • Release tensioner bolt, then turn eccentric of tensioner in
  6. Secure tensioner (Secure bolt 20 Nm; Remove Locking Tool KM-853)
  7. Rotate crankshaft two complete turns in normal direction of rotation to (TDC) on cylinder no. 1, until timing marks are aligned. If pointer of tensioner does not align with corresponding notch mark, then repeat adjustment procedure
  8. Install lower cover of camshaft timing belt (Install 2x bolt 6 Nm)
  9. Install ribbed V-belt tensioner (Install 2x bolt 25 Nm)
  10. Install crankshaft pulley Note: Note position of crankshaft pulley.
    • Counter-hold centre nut on crankshaft sprocket
  11. Install ribbed V-belt
    • Use suitable spanner to rotate tensioner clockwise, then remove
  12. Install upper cover of camshaft timing belt (Push on; Install 2x bolt 6 Nm)
  13. Install intercooler hose to intercooler (Secure clip; Install 4x new cable tie)
  14. Install liner to wheel arch (Install 4x screw, 2x clip)
  15. Install rear road wheel to right side (Install 4x bolt, security bolt; Do not tighten)
  16. Lower vehicle
  17. Secure rear road wheel right side (Tighten 4x bolt, security bolt 90)
  18. Install intercooler hose to throttle body (Secure clip)
  19. Connect battery negative lead (Secure nut and bolt)
  20. Install windscreen wash reservoir (Push fit)
  21. Program all volatile memories
  22. Raise vehicle
  23. Install engine undertray (Install 13x bolt, 13x washer)
  24. Lower vehicle

Crankshaft pulse sensor

Turbo (Z20LET) only.

Remove

  1. Disconnect crankshaft pulse sensor from engine harness (Disconnect harness connector; Release 3x clip)
  2. Remove engine undertray (Raise vehicle; Remove 13x bolt, 13x washer)
  3. Remove ribbed V-belt
    • Using suitable spanner rotate tensioner clockwise, then (Using suitable spanner rotate tensioner clockwise, then Install suitable locking pin)
  4. Remove hose from turbocharger and intercooler (Release 2x clip; Remove, then discard cable tie)
  5. Remove ribbed V-belt idler pulley from accessory bracket (Remove 3x bolt, washer)
  6. Remove accessory bracket from engine cylinder block (Remove 3x bolt)
  7. Remove crankshaft pulse sensor from engine cylinder block (Remove bolt)

Install

  1. Install crankshaft pulse sensor to engine cylinder block (Install bolt 8 Nm)
  2. Install accessory bracket to engine cylinder block (Install 4x bolt 35 Nm)
  3. Install ribbed V-belt idler pulley to accessory bracket (Install 3x bolt, washer 20 Nm)
  4. Install hose to turbocharger and intercooler (Install new cable tie; Secure 2x clip; Remove, then discard cable tie)
  5. Install ribbed V-belt
    • Using suitable spanner rotate tensioner clockwise, then remove
  6. Install engine undertray (Install 13x bolt, 13x washer)
  7. Lower vehicle
  8. Connect crankshaft pulse sensor to engine harness (Connect harness connector; Secure 3x clip)

Balancer shaft unit

Turbo (Z20LET) only.

Remove

  1. Remove engine undertray (Raise vehicle; Remove 13x bolt, 13x washer)
  2. Remove exhaust pipe undertray (Remove 12x bolt, 12x washer, 2x clip)
  3. Lower vehicle
  4. Disconnect battery negative lead
    • Release windscreen washer bottle, then position to one
    • Release bolt, nut
  5. Release intercooler hose from throttle body (Release clip)
  6. Disconnect oxygen sensor harness from engine harness (Release integral clip; Remove, then discard cable tie)
  7. Release harness from chassis (Release 2x clip)
  8. Release harness from heatshield (Release clip)
  9. Remove oil level dipstick (Pull off)
  10. Release rear road wheel from right side
    • Use special socket located under front bonnet
    • Release 4x wheel bolt
  11. Raise vehicle
  12. Drain engine oil (Position collecting container; Remove drain plug; Remove, then discard O ring)
  13. Lower vehicle to suitable working height
  14. Remove rear road wheel from right side (Remove 4x bolt, security bolt)
  15. Remove right rear wheel arch liner (Remove 4x screw, 2x clip)
  16. Remove intercooler hose from intercooler (Release; Remove, then discard 4x cable tie)
  17. Remove toothed belt upper cover (Remove 2x bolt)
  18. Remove ribbed V-belt
    • Using suitable spanner rotate tensioner clockwise, then (Using suitable spanner rotate tensioner clockwise, then Install suitable locking pin)
  19. Remove crankshaft pulley
    • Apply match marks
    • Use spanner to counter-hold centre nut on crankshaft (Use spanner to counter-hold centre nut on crankshaft sprocket)
  20. Remove toothed belt lower cover (Remove 2x bolt)
  21. Rotate crankshaft in normal direction of rotation to Top Dead Centre (TDC) on cylinder no. 1, until timing marks are aligned
  22. Raise vehicle
  23. Remove secondary catalytic converter for exhaust
    • Remove 3x front nut, then discard
    • Remove 3x rear nut, then discard
    • Release rubber mount bracket
    • Release rubber mount
    • Remove gasket from front joint, then discard
  24. Install engine support to engine assembly
  25. Remove heat shield from rear engine mount (Remove 2x bolt from rear engine mount; Remove bolt from engine cylinder block)
  26. Remove engine support from engine assembly
  27. Release lower oil pan from upper oil pan Note: Support lower oil pan when removing to avoid damage to harness for oil level sensor. (Remove 16x bolt)
  28. Release oil level sensor from oil pan (Remove 2x bolt; Remove, then discard oil pan gasket)
  29. Disconnect engine harness from oil level sensor (Release integral clip)
  30. Remove upper oil pan from vehicle (Remove 18x bolt; Remove, then discard gasket)
  31. Remove oil pick up pipe from engine (Remove 2x bolt from oil pump; Remove 2x bolt from balancer shaft unit; Remove, then discard O ring)
  32. Remove balancer shaft unit from engine (Remove 15x bolt; Remove shim)

Install

  1. Install balancer shaft unit to engine (Install 15x bolt 20 Nm + 45°; Clean mating surfaces)
  2. Install oil pick up pipe to engine (Install 2x bolt to oil pump 8 Nm; Install 2x bolt to balancer shaft unit 8 Nm; Install new O ring)
  3. Install upper oil pan to engine
    • Install 18x bolt 20 Nm
    • Apply bead of adhesive sealant compound to rear crankshaft
    • Install new gasket
  4. Connect engine harness to oil level sensor (Secure integral clip)
  5. Secure oil level sensor to lower oil pan (Install 2x bolt 8 Nm)
  6. Install lower oil pan to upper oil pan (Install new oil pan gasket; Install 16x bolt 8 Nm)
  7. Install drain bolt 10 Nm (Lubricate new O ring)
  8. Install engine support to engine assembly
  9. Remove 2x bolt from rear engine mount
  10. Install heat shield to rear engine mount
    • Apply locking compound (Recut 2x bolt thread)
    • Secure bolt to engine cylinder block
  11. Remove engine support from engine assembly
  12. Secure rear engine mount (Secure 2x bolt 46 Nm)
  13. Install secondary catalytic converter for exhaust
    • Install 3x new front nut
    • Install 3x new rear nut
    • Install rubber mount bracket to flange bolt
    • Secure rubber mount
    • Install gasket to front joint
  14. Install toothed belt lower cover (Install 2x bolt 6 Nm)
  15. Install crankshaft pulley (Align match marks; Counter hold centre nut)
  16. Install ribbed V-belt
    • Using suitable spanner rotate tensioner clockwise, then remove (Using suitable spanner rotate tensioner clockwise, then remove suitable locking pin)
  17. Lower vehicle to suitable working height
  18. Install toothed belt upper cover (Install 2x bolt 6 Nm)
  19. Install intercooler hose to intercooler (Secure clip; Install new 4x cable tie)
  20. Install right rear wheel arch liner (Install 4x screw, 2x clip)
  21. Install rear road wheel to right side (Install 4x bolt, security bolt; Do not tighten)
  22. Lower vehicle
  23. Secure rear road wheel (Tighten 4x bolt, security bolt 90)
  24. Install oil level dipstick (Push fit)
  25. Secure intercooler hose to throttle body (Secure clip)
  26. Connect oxygen sensor harness from engine harness (Secure integral clip; Install new cable tie)
  27. Secure harness to chassis (Secure 2x clip)
  28. Secure harness to heatshield (Secure clip)
  29. Connect battery negative lead (Secure nut, bolt; Secure windscreen washer bottle)
  30. Program all volatile memories
  31. Fill engine to correct oil level
    • Start and run engine until oil light goes out
    • Check oil level, adjust if necessary
  32. Install engine undertray (Raise vehicle; Install 13x bolt, 13x washer)
  33. Install exhaust pipe undertray (Install 12x bolt, 12x washer, 2x clip)
  34. Lower vehicle

Balancer shaft backlash

Turbo (Z20LET) only.

Remove

  1. Remove upper oil pan, see “Oil Pan, Upper, Replace”
  2. Remove oil pick up pipe from engine (Remove 2x bolt from oil pump; Remove 2x bolt from balancer shaft unit; Remove, then discard O ring)
  3. Remove front baffle plate from balancer shaft unit (Remove 2x bolt)
  4. Install Screw Measuring Device KM-949
    • Set measuring arm to 9 o'clock position
    • Install short knurled bolt to balancer shaft unit
    • Set dial gauge to zero
  5. Measure balancer shaft unit, tooth backlash
    • Toothed backlash must be measured in 4 different locations
    • Permissible backlash 0.02 mm to
    • Use knurled bolt to rotate shaft
  6. Remove balancer shaft unit from engine (Remove 15x bolt; Remove shim)
  7. Check identification number against table (One shim only to be used)

Install

  1. Install balancer shaft unit to engine (Install shim; Clean all mating surfaces)
  2. Install Screw Measuring Device KM-949 (Set measuring arm to 9 o'clock position; Rotate shaft; Set dial gauge to zero)
  3. Measure balancer shaft unit, tooth backlash
    • Toothed backlash must be measured in 4 different locations
    • Permissible backlash 0.02 mm to
  4. Remove Screw Measuring Device KM-949 from balancer shaft unit
  5. Install oil pick up pipe to engine (Install 2x bolt to oil pump; Install 2x bolt to balancer shaft unit; Install new O ring)
  6. Install front baffle plate to balancer shaft unit (Install 2x bolt 8 Nm)
  7. Install upper oil pan, see “Oil Pan, Upper, Replace”

Pistons and con-rods: removal and installation

Turbo (Z20LET) only.

Remove

  1. Remove upper part of oil pan – see "Oil Pan, Upper, Replace". Remove cylinder head – see "Cylinder Head, Remove and Install".
  2. Remove balancer shaft unit – see "Balancer Shafts, Replace".
  3. Mark order of con-rod bearing caps – bead of con-rod bearing caps points to transmission side. Remove con-rod bearing cap from con-rod.
  4. Remove combustion residue in upper part of the cylinder bore. Remove piston with con-rod upwards from cylinder bore.
  5. Clean and check all parts, replace if necessary.

Install

  1. Adjust the piston ring gaps: First position, top ring (rectangular–section ring) in position, then piston middle ring (Napier ring) in position, intermediate ring of the oil scraper ring in position, steel band rings of the oil scraper ring in position.
  2. Coat piston rings with engine oil and compress with commercially available piston ring compressor.
  3. Push piston into cylinder bore with hammer shaft.
  4. Caution
  5. Installation position: Arrow on piston head points to engine timing side.
  6. Note sequence of con-rod bearing caps. Attach con-rod bearing cap to con-rod with new bolts – con-rod bearing cap bead points to transmission side – tightening torque 35 Nm + 45° + 15°.
  7. Apply a bead of adhesive sealing compound (black) to joints of oil pump and rear crankshaft bearing cap.
  8. Install balancer shaft unit – see "Balancer Shafts, Replace".
  9. Install cylinder head – see "Cylinder Head, Remove and Install".
  10. Install upper part of oil pan – see "Oil Pan, Upper, Replace".

Piston or con-rod replacement

Turbo (Z20LET) only.

Remove

  1. Remove piston and con-rod – see "Piston and Con-rod, Remove and Install".

Install

  1. Before removing piston pin, note installation position of con-rod and piston. Remove retaining ring from piston boss with suitable tool. Remove piston pin from piston and con-rod by hand.
  2. Coat piston pin with engine oil. Press piston pin by hand into piston and con-rod until ring groove is accessible. Insert retaining ring in ring groove of piston.
  3. Install piston and con-rod – see "Piston and Con-rod, Remove and Install".

Con-rod bearing replacement

Turbo (Z20LET) only.

Remove

  1. Remove upper part of oil pan – see "Oil Pan, Upper, Replace".
  2. Remove balancer shaft unit – see "Balancer Shafts, Replace".
  3. Mark order of con-rod bearing caps – bead of con-rod bearing caps points to transmission side.
  4. Remove con-rod bearing cap from con-rod. Press con-rod bearing out of con-rod and con-rod bearing cap.

Clean

  1. Clean con-rod bearing journal and con-rod bearing cap.

Install

  1. Insert new con-rod bearing shells with engine oil. Attach con-rod bearing caps to con-rod with new bolts – tightening torque 35 Nm + 45° + 15°.
  2. Install balancer shaft unit – see "Balancer Shafts, Replace".
  3. Install upper part of oil pan – see "Oil Pan, Upper, Replace".

Piston rings

Turbo (Z20LET) only.

Remove

  1. Remove piston with con-rod- see "Piston and Con-rod, Replace".

Clean

  1. Remove piston rings with piston ring pliers.
  2. Clean piston ring grooves - use ground-down side of old piston ring.

Inspect

  1. Check piston ring gap with feeler gauge by inserting piston ring at narrowest point of the cylinder bore.
  2. Permissible ring gap:
  3. Squared ring:
  4. 0.30 to 0.50 mm.
  5. Tapered ring:
  6. 0.30 to 0.50 mm.
  7. Oil scraper ring:
  8. 0.40 to 1.40 mm.

Install

  1. Check piston ring vertical play with feeler gauge in piston ring groove.
  2. Permissible vertical play:
  3. Squared ring:
  4. 0.02 to 0.04 mm
  5. Tapered ring:
  6. 0.02 to 0.04 mm
  7. Oil scraper ring:
  8. 0.01 to 0.03 mm.
  9. Insert piston rings with piston ring pliers and identification "TOP" upwards in piston.
  10. Piston ring positioning - piston rings (rectangular and tapered compression ring) offset 120°. Oil scraper rings - offset 25 to 50 mm to left and from right of gap in intermediate ring.
  11. Install piston with con-rod - see "Piston and Con-rod, Replace".

Engine vent flange

Turbo (Z20LET) only.

Remove

  1. Disconnect air intake hose from mass air flow meter and turbocharger (Release 2x clip; Move air intake hose to one side)
  2. Remove support bracket with engine lifting eye from cylinder head (Remove bolt)
  3. Remove engine vent hose from cylinder head cover and engine vent flange (Release 2x clip; Pull off)
  4. Remove heat shield from support bracket on cylinder head (Remove 4x bolt, 4x washer)
  5. Remove engine vent flange from engine cylinder block (Remove, then discard gasket)

Install

  1. Install new engine vent flange to engine cylinder block (Clean mating surfaces; Use new gasket; Install 2x bolt 25 Nm)
  2. Install heat shield to support bracket on cylinder head (Install 4x bolt, 4x washer)
  3. Install engine vent hose to cylinder head cover and engine vent flange (Secure 2x clip; Push on)
  4. Install support bracket with engine lifting eye to cylinder head (Apply locking compound)
  5. Connect air intake hose to mass air flow meter and turbocharger (Secure 2x clip)

Sources & credit

Written up from these owners' original posts. Thanks to everyone who contributed.

  • Vauxhall TIS: Crankshaft, Replace (Engine Removed) (Z20 LET) by Vauxhall TIS
  • Vauxhall TIS: Crankshaft Bearing Clearance, Check (Micrometer Method), (Z 20 LET) by Vauxhall TIS
  • Vauxhall TIS: Crankshaft Bearing Clearance, Check (Plastigage Method), (Z 20 LET) by Vauxhall TIS
  • Vauxhall TIS: Con-rod Bearing Play, Check (Micrometer Method), (Z 20 LET) by Vauxhall TIS
  • Vauxhall TIS: Con-rod Bearing Play, Check (Plastigage Method), (Z 20 LET) by Vauxhall TIS
  • Vauxhall TIS: Crankshaft Oil Seal, Flywheel Side, Replace (Z 20 LET) by Vauxhall TIS
  • Vauxhall TIS: Crankshaft Oil Seal, Timing Side, Replace (Z 20 LET) by Vauxhall TIS
  • Vauxhall TIS: Crankshaft Pulley, Replace (Z20 LET) by Vauxhall TIS
  • Vauxhall TIS: Sprocket, Crankshaft, Timing Belt, Replace (Z20 LET) by Vauxhall TIS
  • Vauxhall TIS: Sensor, Crankshaft Pulse, Replace (Z 20 LET) by Vauxhall TIS
  • Vauxhall TIS: Balancer Shaft Unit, Replace (Z20 LET) by Vauxhall TIS
  • Vauxhall TIS: Balancer Shaft Backlash, Check and Adjust (Z20 LET) by Vauxhall TIS
  • Vauxhall TIS: Piston and Con-rod, Remove and Install (Z20 LET) by Vauxhall TIS
  • Vauxhall TIS: Piston or Con-Rod, Replace (Z20 LET) by Vauxhall TIS
  • Vauxhall TIS: Con-rod Bearing, Replace (Z20 LET) by Vauxhall TIS
  • Vauxhall TIS: Piston Rings, Replace (Z 20 LET) by Vauxhall TIS
  • Vauxhall TIS: Engine Vent Flange, Replace (Z20 LET) by Vauxhall TIS

Last updated 2026-10-25

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