Connecting rod half bearings

Make

Alfa Romeo

Model

145/146 Factory Service Manual

Year

1994–1999

Section

Engine › Connecting rod half bearings

Technical data and maintenanceConnecting rod half bearings

Connecting rod half bearings

Unit: mm
Thickness of connecting rod half bearings "a"	Class A - Red 1.527 ÷ 1.531
	Class B - Blue 1.530 ÷ 1.534
	Class C - Yellow 1.533 ÷ 1.537
Undersize 0.127
Operating clearance connecting rod pins and their half bearings	Class A - Red
	Class B - Blue 0.03 ÷ 0.056
	Class C - Yellow

Seal rings

Unit: mm
Thickness of rings "a"	First ring 1.170 ÷ 1.190
	Second ring 1.475 ÷ 1.490
	Oil scraper ring 2.975 ÷ 2.990
Ring gap "b" (1)	First ring 0.25 ÷ 0.50
	Second ring 0.30 ÷ 0.50
	Oil scraper ring 0.25 ÷ 0.45
Axial play between seal rings and seats	First ring 0.030 ÷ 0.070
	Second ring 0.020 ÷ 0.055
	Oil scraper ring 0.020 ÷ 0.055
(1) To be measured in the checking ring nut or in the cylinder

Gudgeon pins

Unit: mm
Outside diameter of gudgeon pins "a"	19.996 ÷ 20.000
Clearance between gudgeon pins and their seats on pistons	0.002 ÷ 0.011

CYLINDER HEAD

Head

Unit: mm
Diameter of sedi valve guide seats "a"	12.950 ÷ 12.977
Valve guide protrusion "b"	11.25 ÷ 11.75
Diameter of valve cup seats "c"	33.000 ÷ 33.025
Diameter of valve seat housing "d"	Intake 34.989 ÷ 35.014
	Exhaust 28.991 ÷ 29.012
Minimum depth of combustion chamber "e"	13 ± 0.2
Maximum error of flatness of head lower surface	0.1
Diameter of camshaft supports "f"	26.045 ÷ 26.070
Diameter of timing variator support "g"	55.990 ÷ 56.015

02 Maintenance