11A-4
Engine-proper
STRUCTURE AND OPERATION
P29712
1 Cylinder head
2 Head idler gear
3 Camshaft frame
4 Camshaft gear (Exhaust side)
5 Exhaust camshaft
6 Camshaft gear (Inlet side)
7 Inlet camshaft
8 Exhaust valve
9 Exhaust rocker shaft
10 Short rocker
11 Rocker shaft spring
12 Long rocker
13 Rocker cover
14 Short rocker
15 Inlet rocker shaft
16 Valve spring
17 Inlet valve
18 Piston
19 Flywheel
20 Connecting rod
21 Balance shaft RH
22 Rear plate
23 Crankshaft
24 Upper crankcase
25 Lower crankcase
26 Balance shaft LH
27 Injection pump gear
28 Balance shaft gear LH
29 Vacuum pump gear
30 No. 1 idler gear
31 Crankshaft gear
32 Oil pump gear
33 Balance shaft gear RH
34 Fan shaft assembly
35 Idler gear assembly
The 4M50T2 engine is of the double overhead camshaft (DOHC) type. The valve mechanism and timing gear arrangement
is illustrated above.
3
2
1
35
34
33
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
11A-5
11A
Cylinder Head, Cylinder Head Gasket, Camshaft and Camshaft Frame
1 Bolt (× 2)
2 Bolt (× 13)
3 Camshaft frame
4 Camshaft bearing (Upper)
5 Exhaust camshaft
6 Camshaft bearing (Lower)
7 Inlet camshaft
8 Cylinder head
9 Cylinder head gasket
10 Cylinder head bolt
A : Locating pin
B : Locating pin
C : Notched portion
* : Front
• The camshafts 5 and 7 have their journals supported by the cylinder head 8, and are held down from above by the
camshaft frame 3.
• The camshaft bearings 4 and 6, both upper and lower, are identical parts. When they are reassembled, however, be
sure to reinstall them in their original positions, as they were before disassembly.
• The exhaust camshaft 5 and the inlet camshaft 7 have the same gears but use different cams. Use care not to confuse
them at reassembly.
• As for the cylinder head gasket 9, select and use one of proper thickness suitable for the projection of the piston. The
thickness of gaskets is identifiable by a difference in the shape of the notched portion C.
• The bolts 2 (× 13) are threaded into the cylinder head 8, whereas the bolts