Checking the pistons
- Make
- Alfa Romeo
- Model
- 145/146 Engines, 146 Bodywork and Engine Overhaul Manual
- Year
- 1994–2001
- Section
- Overhauling › Checking the pistons
‹ Prev Checks and inspection crankcaseNext › Checking the clearance between connecting rod journals and the corresponding half bearings
Engine overhaul: 2.0 Twin Spark 16VChecking the pistons
Checking the pistons
- Measure the outside diameter of the pistons and check that it is within the specified limits.
| Outside diameter of pistons (1) | |
|---|---|
| Class A (Blue) | 82.952 ÷ 82.962 mm |
| Class B (Pink) | 82.959 ÷ 82.971 mm |
| Class C (Green) | 82.968 ÷ 82.978 mm |
| Oversize of 0.1 mm | |
(1) To be measured at right angles to the gudgeon pin hole at a distance of 12.5 mm from the lower edge of the piston skirt.
- Calculate the clearance between the cylinder and the piston and check that it is within the specified limits.
| Clearance between piston and cylinder | |
|---|---|
| 0.038 ÷ 0.062 mm |
- Check that the difference in weight between the pistons complete with gudgeon pins and seal rings is within the specified limits.
| Difference in weight between pistons | |
|---|---|
| ± 5 g |
Checking the seal ring gap
- Insert the seal rings in the cylinder, check that they adhere to the whole circumference and that the gap is within the specified limits.
| Ring gap | |
|---|---|
| First ring | 0.25 ÷ 0.50 mm |
| Second ring | 0.30 ÷ 0.50 mm |
| Oil scraper ring | 0.25 ÷ 0.45 mm |
Checking the play between gudgeon pins and seats on pistons
- Measure the outside diameter of the gudgeon pins and check that it is within the specified limits.
| Outside diameter of gudgeon pins | |
|---|---|
| 19.996 ÷ 20.000 mm |
- Measure the diameter of the pin mating hole in the piston and check that it is within the specified limits.
| Diameter of pin seat in pistons | |
|---|---|
| 20.002 ÷ 20.007 mm |
‹ Prev Checks and inspection crankcaseNext › Checking the clearance between connecting rod journals and the corresponding half bearings
Parts & tools for this job For 1994 Alfa Romeo 145/146
- PARTEngine gasket setSearch: Alfa Romeo 145/146 1994 engine gasket set
- TOOLTorque wrenchSearch: 3/8 inch torque wrench
- TOOLFeeler gauge setSearch: feeler gauge set
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