ZEST/BOLT

ENGINE 1.3 QUADRAJET (75PS)

Above is an example of identifying the main journal

and crankpin grade referring to an engine with nominal

diameter main journals (51.000 mm).

1) Crankpin alphabetical identification code - BBBB

(the same for all bearings): the first letter from the

left refers to the first timing side bearing.

2) Main journal alphabetical identification code -

AAAAA (the same for all bearings): the first letter

from the left refers to the first timing side bearing.

3) Alphabetical identification code for thrust washers

- R.

Only use the alphabetical codes for references 1, 2

and 3 in the diagram, all the other codes on the

counter-weight should not be used.

For the identification of the main journal grade, refer

to the alphabetical code 2 shown in the diagram.

In the case of the diagram, for example, the letter

code AAAAA (Grade A - Normal) indicates that all

five bearings are prepared for the fitting of half-

bearings with a Red coloured paint mark on the edge;

as a result, specific half-bearings should be identified

for different alphabetical codes (bearing grade).

The letter code stamped on the timing side counter-

weight is required for selecting the grade.

Normal grades are usually used on new engines with

undersizes only used in exceptional cases.

ALLOCATION OF HALF-BEARINGS TO MAIN

JOURNALS:

Having defined the grade for each crankshaft bearing

(to which a specific diameter corresponds according

to the grade), it is necessary to select the p air of

Main journal grade

Diameter

Paint Mark

grade A (normal) 51.000 ~ 50.994 mm RED paint mark

grade B (normal), 50.994 ~ 50.988 mm BLUE paint mark

grade C (normal), 50.988 ~ 50.982 mm YELLOWpaint mark

grade AM

(0.127 undersize) 50.873 ~ 50.867mm BROWN paint mark

grade BM

(0.127 undersize) 50.867 ~ 50.861mm, GREEN paint mark

grade CM

(0.127 undersize) 50.861 ~ 50.855mm BLACK paint mark

Minimum

Maximum

0.025 mm

0.052 mm

bearings which are the same colour. This is designed

to guarantee the optimum operational clearances for

all the bearings.

Lastly, we wish to point out that, generally , the

clearance between the main journal and the half-

bearing, obtained through the selection method

indicated above, should be within the following values: