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.
Other jobs from the same factory chapter: Crankshaft and bearing clearances (Turbo); Crankshaft seals, pulley, sprocket and pulse sensor (Turbo); Balancer shaft unit and backlash (Turbo).
Pistons and con-rods: removal and installation
Turbo (Z20LET) only.
Remove
- Remove upper part of oil pan – see "Oil Pan, Upper, Replace". Remove cylinder head – see "Cylinder Head, Remove and Install".
- Remove balancer shaft unit – see "Balancer Shafts, Replace".
- 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.
- Remove combustion residue in upper part of the cylinder bore. Remove piston with con-rod upwards from cylinder bore.
- Clean and check all parts, replace if necessary.
Install
- 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.
- Coat piston rings with engine oil and compress with commercially available piston ring compressor.
- Push piston into cylinder bore with hammer shaft.
- Caution
- Installation position: Arrow on piston head points to engine timing side.
- 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°.
- Apply a bead of adhesive sealing compound (black) to joints of oil pump and rear crankshaft bearing cap.
- Install balancer shaft unit – see "Balancer Shafts, Replace".
- Install cylinder head – see "Cylinder Head, Remove and Install".
- Install upper part of oil pan – see "Oil Pan, Upper, Replace".
Piston or con-rod replacement
Turbo (Z20LET) only.
Remove
- Remove piston and con-rod – see "Piston and Con-rod, Remove and Install".
Install
- 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.
- 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.
- Install piston and con-rod – see "Piston and Con-rod, Remove and Install".
Con-rod bearing replacement
Turbo (Z20LET) only.
Remove
- Remove upper part of oil pan – see "Oil Pan, Upper, Replace".
- Remove balancer shaft unit – see "Balancer Shafts, Replace".
- 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. Press con-rod bearing out of con-rod and con-rod bearing cap.
Clean
- Clean con-rod bearing journal and con-rod bearing cap.
Install
- 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°.
- Install balancer shaft unit – see "Balancer Shafts, Replace".
- Install upper part of oil pan – see "Oil Pan, Upper, Replace".
Piston rings
Turbo (Z20LET) only.
Remove
- Remove piston with con-rod- see "Piston and Con-rod, Replace".
Clean
- Remove piston rings with piston ring pliers.
- Clean piston ring grooves - use ground-down side of old piston ring.
Inspect
- Check piston ring gap with feeler gauge by inserting piston ring at narrowest point of the cylinder bore.
- Permissible ring gap:
- Squared ring:
- 0.30 to 0.50 mm.
- Tapered ring:
- 0.30 to 0.50 mm.
- Oil scraper ring:
- 0.40 to 1.40 mm.
Install
- Check piston ring vertical play with feeler gauge in piston ring groove.
- Permissible vertical play:
- Squared ring:
- 0.02 to 0.04 mm
- Tapered ring:
- 0.02 to 0.04 mm
- Oil scraper ring:
- 0.01 to 0.03 mm.
- Insert piston rings with piston ring pliers and identification "TOP" upwards in piston.
- 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.
- Install piston with con-rod - see "Piston and Con-rod, Replace".
Engine vent flange
Turbo (Z20LET) only.
Remove
- Disconnect air intake hose from mass air flow meter and turbocharger (Release 2x clip; Move air intake hose to one side)
- Remove support bracket with engine lifting eye from cylinder head (Remove bolt)
- Remove engine vent hose from cylinder head cover and engine vent flange (Release 2x clip; Pull off)
- Remove heat shield from support bracket on cylinder head (Remove 4x bolt, 4x washer)
- Remove engine vent flange from engine cylinder block (Remove, then discard gasket)
Install
- Install new engine vent flange to engine cylinder block (Clean mating surfaces; Use new gasket; Install 2x bolt 25 Nm)
- Install heat shield to support bracket on cylinder head (Install 4x bolt, 4x washer)
- Install engine vent hose to cylinder head cover and engine vent flange (Secure 2x clip; Push on)
- Install support bracket with engine lifting eye to cylinder head (Apply locking compound)
- Connect air intake hose to mass air flow meter and turbocharger (Secure 2x clip)