Machining valve seats

Data

Intake

Exhaust

Valve seat width b

1.3-1.6

2.5-2.9

Permissible runout of valve seat

0.03

Minimum distance “a” with new valves and new valve seats

Intake

+ 0.17 to-0.23

Exhaust

+ 0.12 to -0.28

Maximum distance “a” with new valves and machined (ref inished) valve seats

Intake

1.0

Exhaust

The max. distance is reduced by the same amount by which the cylinder head parting surface has been ref inished.

Valve stem wear (wear limit)

0.05

Special tools

Valve adjusting wrench 14 mm (2 each)

615 589 00 01 00

Holding wrench for valve spring retainer

615 589 00 03 00

Assembly mandrel for valve stem seals Intake and exhaust

617 589 00 43 00

Plug gage 10 mm dia. for intake and exhaust valve guide

615 589 00 21 00

05.8-291/1 F2

Cylinder head clamping fixture

e.g. made by Christ, D-6801 Neckarhausen Order No. DBK 60-2

Valve seat machining tool

e.g. made by Hunger, D-8000 Miinchen Type VDNSL 1/45/30, order No. 236.03.308

Test kit for valve seats

e.g. made by Hunger, D-8000 Munchen Order No. 216.93.300

Clamp cylinder head into clamping fixture for disassembly and machin­ing.

Machine valve seats with valve machin­ing tool, with valve seat grinding machine or with valve seat milling cutter.

1 Check valve guides and replace, if required (05-285).

05.8-291/2 F2

2    Machine valve seat (30°) (refer to operating in­structions of tool manufacturer).

Release pilot (013) only after runout of valve seat has been checked.

3   Measure valve seat width b and correct below to 60°, if required.

If required, also correct clearance (/3) to 60°.

4 Check runout of valve seat.

For this purpose, slip test sleeve (017) with dial gage holder (016) and dial gage on pilot (013) and rotate test sleeve. The permissible runout of 0.03 mm should then not be exceeded.

013 Pilot

016    Dial gage holder

017    Test sleeve

5 Introduce new valve and measure max. distance a.

05.8-291/3 F2