Inspection of Inlet Valve, Exhaust Valve and Valve Guide

08028-0D/H5250/94.08.12

L23/30H

Dismantling of Inlet and Exhaust Valve Spindles

1) Land and fasten the cylinder head upon the special work table and remove the lifting tool.

Or as an Alternative:

Land the cylinder head on the floor upon wooden supports and remove the lifting tool.

2) Mount the supporting devices for the valve spindle heads on the work table.

Or as an alternative:

Place wooden blocks under the valve spindle heads.

3) Turn back the rocker arm and remove the spring-loaded valve bridge over the valve spindles.

A

B

Fig 1.

4)Mount the tool for mounting af valves, see fig 2.

5)Compress the valve springs by tightening nut A, see fig 1.

6)Remove the cone rings, see fig 2.

7)Release the springs again.

8)Remove nut A and traverse B, see fig 1.

9)Remove valve rotator and springs.

Fig 2.

table and take out the valve spindle.

11) Repeat point 4 - 10 to remove the two other valve spindles.

Inspection of Valves/Valve Seats

A slight grinding of valve/valve seat can be carried out by means of the handle as shown, see fig 3.

If the valve seat is heavily burnt or scarred, it should be ground using the valve seat grinder, see working card 505-01.10.

Inspection of Valve Guide

Fig 3.

08028-0D/H5250/94.08.12

Too much clearance between valve spindle and spindle guide may cause:

-increased lub. oil consumption.

-fouling up of the spindle guide and thus give the risk of a sticking valve spindle.

Too much clearance also means insufficient guidance of the valve spindle, and thus bad alignment between spindle head and valve seat ring.

In connection with overhaul of the cylinder head, the valve spindle guides should be cleaned, inspected and measured for wear.

If the inner diameter of the valve spindle guide exceeds the tolerance, see page 500.35, the valve spindle guide must be replaced. See working card 505-01.20.

Mounting of Valve Spindle

12) For mounting of valve spindle follow the

Fig 4.

instructions in point 4 - 10 in reversed order.

Max inner diameter,

see page 500.35.

08028-0D/H5250/94.08.12

L23/30H

Reconditioning of Valve Seat Ring

Reconditioning of valve seat rings by machining is carried out by means of a grinding machine, the pilot spindle of which is to be mounted in the valve spindle guide. For operation of the grinding machine, see separate instructions.

Grinding of Valve Seats

Grinding of valve seat rings should be carried out according to the following sequence:

1)Grind the seating surface with a feed at an angle "A" of 30° ± 0,10°0. .

2)Continue the grinding until a clean and uniform surface condition has been obtained.

3)Carry out the final grinding with a feed in the direction inside and outwards. Normally, the best surface quality is obtained this way.

"A" 30 ± 0,10°0

"R"

"S"

Fig 1. Valve Seat Ring

Scrapping of Valve Seat Rings

Normally, the valve seat ring can be reconditioned several times.

However, when the seat "S" has been ground to such an extent that the recess "R" disappears, see fig 1, the valve seat ring has to be scrapped and a new one must be installed, see working card 505-01.35

Reconditioning of Valve Spindle

Reconditioning by machining is carried out with the valve spindle being rotated in a turning lathe and a special grinding machine mounted on the tool post of the turning latch.

Grinding of Valve Spindle

For operation of the grinding machine, see separated instructions.

1) Grind the seating surface with a feed at an angel "A" of 30° ± 0.

0,25°.

2)Continue the grinding until a clean and uniform surface condition has been obtained.

3)Check the height "H"1 after completing the grinding, see fig 2.

"H"1 has as a minimum to be as indicated on page 500.35.

If measured to be less, the spindle has to be scrapped.

4) After assembling the valves, check - on account

"A" 30° ± 0,25°0