BMW 1989-1995 525i Service Manual page 117

CYLINDER HEAD AND VALVETRAIN
Table f. Valve Guide Specifications
116-19
Specifications
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M20 Engine M30 Engine M50 Engine M50TU Engine M60 Engine
(1991 -1992) (1993-0n)
Valve guid e wear. maxim um (valve tilt
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0.8 mm (0.031 in.)
0.8 mm (0.03 1 in.) 0.5 mm (0.020 in.) 0.5 mm (0.020 in.) 0.5 mm (0.020 in.)
cleara nce measured with new valve)
Va lve guide inside diameter. installed
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(tolerance per ISO allowance H7)
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standard 17.0 mm (0.275 in.) 8.0 mm (0.31 5 in.) 7.0 mm (0.275 in.) 6.0 mm (0.236 in.) 6.0 mm (0.236 in.)
-
oversize 1 ' 7.1 mm (0.280 in.) 8.1 mm (0.319 in.) 7.1 mm (0.280 in.) 6.1 mm (0.240 in.) 6.1 mm (0.240 in.)
•
-
oversize 2
17.2 mm (0 .283 in.)
8.2 mm (0.323 in.) 7.2 mm (0.283 in.) 6.2 mm (0.244 in.) 6.2 mm (0.244 in.)
Table g. Valve Specifications
Specification M20 Engine M30 Engine M50 Engine M50TU Engine
M60 M60
(1991-1992) (1993·later) (3.0 liter) (4.0 liter)
-
.-
-
Valve head dia.
Intake 42 mm (1 .635 in.) 47 mm (1.850 in.) 33.0 mm (1.299 in.) 33 .0 mm (1 .299 in.) 32.0 mm (1.260 in.) 35.0 mm (1.378 in.)
exhaust 36 mm (1.417 in.) 38 mm (1 .496 in.) 30.5 mm (1.201 in.) 30.5 mm (1.201 in.) 28.5 mm (1.122 in.) 30.5 mm (1 .201 in.)
- - -
--
Minimum valve
head thickness
intake 1.3 mm (0.05 1 in.) 1.3 mm (0 .05 1 in.)
N /A N /A N/A N/A
exhaust
2.0 mm (0.079 in.) 2.0 mm (0 .079 in.)
N/A N /A N/A
N/A
- - -
Va lve lace angl e 45'
45 · 45 ·
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45·
45 '
45·
-
Valve stem dia.
sta nda rd
1
7.0 mm (0.280 in.) intake 8.0 mm (0 .315 in.) 6.975 mm (0.275 in.) 5.975 -0.0 15 mm 5.975 -0.0 15 mm 5.975 -0.015 mm
(0.235 -0.0006 in.) (0.235 -0.0006 in.)
(0.235 -0.0006 in.)
exhaust
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7.0 mm (0.280
in.) 8.0 mm (0 .3 15 in.) 6.975 mm (0.275 in.) 5.960 -0.0 15 mm 5.960 -0.0 15 mm 5.960 -0.0 15 mm
(0.2346 -0.0006 in.) (0.2346 -0.0006 in.) (0.2346 -0.0006 in.)
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Oversize 1
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intake 7.1 mm (0.280 in.) 8.1 mm (0 .3 19 in.)
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7.1 mm (0.280 in.) 6.075-0.015 mm 6.075-0.015 mm 6.075-0.0 15 mm
(0.239-0.0006 in.) (0.239-0.0006 in.) (0.239-0.0006 in.)
exhaust 7.1 mm (0.280
in.) 8.1 mm (0 .3 19 in.) 7.1 mm (0.280 in.) 6.060-0.015 mm 6.060-0.0 15 mm 6.060-0.0 15 mm
(0.239-0.0006 in.) (0.239-0.0006 in.) (0.239-0.0006 in.)
Ove rsize 2
intake 7.2 mm (0.283 in.) 8.2 mm (0 .323 in.) 7.2 mm (0.283 in.) 6.175-0.015 mm 6.175-0.015 mm 6.175-0.015 mm
exhaust
7.2 mm (0.283 in.) 18.2 mm (0. 323 in.)
(0.243-0.0006 in.) (0.243-0.0006 in.)
(0.243-0 .0006 in.)
7.2 mm (0.283 in.) 6.160-0.015 mm 6.160-0.015 mm 6.160-0.015 mm
,
(0.243-0.0006 in.) (0.243-0.0006 in.) (0.243-0 .0006 in.)
NOTE -
BMW special tool no. 11 1 250 (M20. M30. M50 en-
gines)
or
special tool no. 11 2 090 (M50TU VANOS) is
available to remove the valve stem oil seals. As an st-
ternative. standard valve seal removal too ls are avail-
able (rom most automotive parts stores. See Fig. 40.
When installing the valve stem oil seals, the use of BMW
special tool 11 1 200 is recommended. Lubricate the new
seals and install them using hand pressure only . Be sure to in-
stall the valve spring seat before installing the seal.
Valve Seats
The valve seats should be resurfaced whenever new
valves or valve guides are installed. Cutters are required to reo
surface the seats. Always check the valves for leaks after reo
conditioning a valve seat as described above.
NOTE-
Standard size replacement valve seats are not avail-
able (rom BMW Replacement valve seats are only
available (rom BMW in 0.4 mm oversize (oversized in
both height and diameter).
CYLINDER HEAD AND VALVETRAIN RECONDITIONING