Inspection and Cleaning.

TM 10-3930-621-34

b. Inspection and Cleaning.

(1) Examine valve carefully for fit in guide,

(4) Check tension of each valve spring with a

excessive wear, warping or burning.

suitable spring scale.

(2) Remove all carbon and burnt oil.

(5) Tension of all springs should be equal.

(3) Inspect spring coils for bright spots that may

Spring free length is 2.250 inch. Compressed to 1.938

be an indication of weakness when found

inch the scale should read approximately 36 pounds.

(6) Replace defective parts as authorized.

1. Poppet valve

12.

Flat washer

2. Intake salve guide

13.

Cotter pin

3. Exhaust valve guide

14.

Machine bolt

4. Spring

15.

Screw

5. Spring retainer

16.

Gear

6. Valve spring lock

17.

Retaining ring

7. Retainer cap

18.

Lock plate

8. Valve tappet

19.

Thrust plate

9. Center sleeve bearing

20.

Key

10. Front sleeve bearing

21.

Camshaft

11. Nut

22.

Rear sleeve bearing?

Figure 3-6. Cam shaft, valves and tappets, exploded view

c. Grinding.

(1) The accuracy of grinding valve seats

If it does have any upper end movement the seat not be

depends upon the condition of the valve guide and the

ground true.

pilot mandrel's fit, both in the guide itself, and the hub of

(2) Guides that are worn too much to give the

the grinder stone. It is vitally important to make sure that

mandrel solid support should be replaced before grinding

the mandrel is a snug fit in the valve guide, and does not

is attempted.

The manufacturers instructions for

wobble at the upper end.

dressing the grinding wheel must be owed to secure

smooth, accurate seats.

3-8