Westerbeke 20B TWO Manual de instalación descargar pdf (Pagina 50)

ENGINE

ADJUSTMENTS

NOTE:

WESTERBEKE recommends that the following engine adjust-

ments be peiformed by a competent engine mechanic. The information

below

provided to assist the mechanic.

CYLINDER

HEAD

BOLT

TIGHTENING

SEQUENCE

FRONT

SUB

BOLTS

"'"'

SUB

BOLTS~

TWO

CYLINDER

20B

·TWO

Cylinder head bolts must be tightened before valve

adjustment.

TORQUING

THE

CYLINDER

HEAD

BOLTS

After the initial break-in period (approximately 50 hours), the

cylinder head bolts should be re-torqued.

Loosen the cylinder head bolts one half tum in the order

shown. (The engine should be cold). Then tighten the bolts in

the sequence shown below.

One bolt at a time. Tighten the

rocker cover stud securely.

NOTE:

The rocker shaft assembly should be removed

for

access

the cylinder head bolts.

TORQUE

SPECIFICATIONS:

30B/30C-

THREE

Bolts

#1,

#2,

-14.4-

21.71b-ft

(2.0-

3.0

Kg-m)

Bolts#

#5, #6, #7,

#8,

#9,

#10,

#11-

54.2-

61.4

lb-ft

(7.5-

8.5

Kg-m)

20B-TWO

Bolts

#1,

14.4

21.7

lb-ft

(2.0

3.0

Kg-m)

Bolts#

#4,

#6, #7,

#8- 54.2-

61.4

lb-ft

(7.5-

8.5

Kg-m)

ROCKER

SHAFT

HOLD~DOWN

BOLTS

0 All main bolts are 14mm across the bolt head flats.

0 All sub bolts are 12mm across the bolt head flats.

0 Rocker shaft hold-down bolts are 12mm across the bolt

head flats.

0 Rocker cover hold-down cap nuts are lOmm socket (snug).

VALVE

CLEARANCE

ADJUSTMENT

The valve clearance must be adjusted every 500 operating

hours or whenever the valve rocker

abnormally noisy.

Valve adjustment should

done when the engine

cold.

Cold engine valve clearance

O.OlOin

(0.25mm).

Cylinder head bolts must be re-torqued before

valve adjustment.

MARK

PULLEY

VALVE

CLEARANCE

.INSPECTION

TIMING

MARKS

Pull off the air breather pipe from the rocker cover

and take off the rocker cover bolts. Adjust the valve

clearances at TDC (Top Dead Center) for each cylinder

when they are on their compression stroke.

2. Adjust all valve clearances at the TDC (Top Dead Center)

the compression stroke for each cylinder. Take care to

align the

TDC

timing mark on the crankshaft pulley

exactly with the indicator mark on the gear case, as

shown on the illustration.

these marks are not exactly

aligned, the values may be pushed

by the piston,

depending on the position

the cam lobe.

3. Confim1 that the valves do not move up or down when

the crankshaft is turned slightly in either direction from

the TDC mark.

4. Align the mark (as shown) for TDC for the No.1 cylinder

on its compression stroke and adjust the valve clearances

for both intake and exhaust valves for the No.1 cylinder

with the engine cold.

Engines

& Gener:ators

1 2 ... 45 46 47 48 49 50 51 52 53 54 55 ... 71 72

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Westerbeke 20B TWO Manual de instalación Pagina 50

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