Volkswagen Corrado (1993 year). Manual - part 137

 

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Volkswagen Corrado (1993 year). Manual - part 137

 

 

ENGINE OVERHAUL PROCEDURES - GENERAL INFORMATION 

         ASSEMBLING PISTON & CONNECTING ROD

         Install proper fitted piston on connecting rod for proper
cylinder. Ensure piston marking on top of piston marked is in
correspondence with connecting rod and cap number. See Fig. 14.

Fig. 14:  Piston Pin Installation - Typical
This Graphic For General Information Only

         Lubricate piston pin and install in connecting rod. Ensure
piston pin retainers are fully seated (if equipped). On pressed type
piston pins, follow manufacturer's recommended procedure to avoid
distortion or breakage.

         CHECKING PISTON RING CLEARANCES

         Piston rings must be checked for side clearance and end gap.
To check end gap, install piston ring in cylinder which it is to be
installed. Using an inverted piston, push ring to bottom of cylinder
in smallest cylinder diameter.
         Using feeler gauge, check ring end gap. See Fig. 15. Piston
ring end gap must be within specification. Ring breakage will occur
with insufficient ring end gap.
         On some manufacturers, insufficient ring end gap may be
corrected by using a fine file while other manufacturers recommend
using another ring set. Mark rings for proper cylinder installation
after checking end gap.

ENGINE OVERHAUL PROCEDURES - GENERAL INFORMATION 

         For checking side clearance, install rings on piston. Using
feeler gauge, measure clearance between piston ring and piston ring
land. Check side clearance in several areas around piston. Side
clearance must be within specification.
         If side clearance is excessive, piston ring grooves can be
machined to accept oversized piston rings (if available). Normal
practice is to replace piston.

         PISTON & CONNECTING ROD INSTALLATION

         Cylinders must be honed prior to piston installation. See
CYLINDER HONING under CYLINDER BLOCK in this article.
         Install upper connecting rod bearings. Lubricate upper
bearings with engine oil. Install lower bearings in rod caps. Ensure
bearing tabs are properly seated. Position piston ring gaps according
to manufacturers recommendations. See Fig. 16. Lubricate pistons,
rings and cylinder walls.

ENGINE OVERHAUL PROCEDURES - GENERAL INFORMATION 

         Install ring compressor. Use care not to rotate piston rings.
Compress rings with ring compressor. Install plastic tubing protectors
over connecting rod bolts. Install piston and connecting rod assembly.
Ensure piston notch, arrow or "FRONT" mark is toward front of engine.
See Fig. 17.

Fig. 17:  Installing Piston & Connecting Rod Assembly - Typical
This Graphic For General Information Only

         Carefully tap piston into cylinder until rod bearing is

ENGINE OVERHAUL PROCEDURES - GENERAL INFORMATION 

         CONNECTING ROD SIDE CLEARANCE

         Position connecting rod toward one side of crankshaft as far
as possible. Using feeler gauge, measure clearance between side of
connecting rod and crankshaft. See Fig. 18. Clearance must be within
specifications.

Fig. 18:  Measuring Connecting Rod Side Clearance - Typical
This Graphic For General Information Only

         Check for improper bearing installation, wrong bearing cap
or insufficient bearing clearance if side clearance is insufficient.
Connecting rod may require machining to obtain proper clearance.
Excessive clearance usually indicates excessive wear at crankshaft.
Crankshaft must be repaired or replaced.

         MAIN & CONNECTING ROD BEARING CLEARANCE

         Plastigage Method
         Plastigage method may be used to determine bearing clearance.
Plastigage can be used with an engine in service or during reassembly.
Plastigage material is oil soluble.
         Ensure journals and bearings are free of oil or solvent.
Oil or solvent will dissolve material and false reading will be
obtained. Install small piece of Plastigage along full length of
bearing journal. Install bearing cap in original location. Tighten
bolts to specification.

CAUTION: DO NOT rotate crankshaft while Plastigage is installed.
         Bearing clearance will not be obtained if crankshaft is

 

 

 

 

 

 

 

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