the engine block

disassembled the head from the block..
removed the pistons from  the crankshaft,then removed the crankshaft itself

Main journals.

	1	2	3	4	5
Diameter A1	49.844	49.943	49.944	50	50
Diameter B1	49.943	50	50	50	49.944
Diameter A2	49.894	49.944	49.944	49.945	50
Diameter B2	49.942	49.943	50	49.944	49.945
Ovality A minus B	0.601
Largest diameter A1 or B1	B1	B1	B1	Same	A1
Smallest diameter A2 or B2	a2	b2	A2	B2	B2
Taper A1 minus A2	0.05	0.001	0	0.055	0
STD. diameter
Smallest diameter (from A or B)	A	B	B	B	A
Wear

Big end journal specification:-

Diameter 39 – 40 (0.05 mm out of round) mm

Taper limit mm

Ovality limit mm

	Cyl 1	Cyl 2	Cyl 3	Cyl 4
Diameter A1	40.04	40.04	40.04	40..04
Diameter B1	40.04	40.04	40.04	40.04
Diameter A2	40.04	40.04	40.04	40.04
Diameter B2	40.04	40.04	40.04	40.04
Ovality A minus B	0	0	0.001	0
Largest diameter A1 or B1	Same	Same	A1	Same
Smallest diameter A2 or B2	Same	Same	B1	Same
Taper A minus B	0	0.002	0.001	0
STD. diameter
Smallest diameter (from A or B)	Same	40.042	40.043	40.043
Wear

above is the crankshaft with pistons on the side and the table of results for the journals taper and ovality against the provided specification sheet for a Mazda 323 engine.They were with in specs.

The table below show results of a visual check on the piston rings.

	Cylinder 1	Cylinder 2	Cylinder 3	Cylinder 4
Top ring	Broken	Ok	Ok	Ok
Second ring	Ok	Ok	Ok	Ok
Third ring	Ok	Ok	Ok	Ok
Oil ring	Ok	Ok	Ok	Ok

the pistons were measure for the skirt diameters with micrometer and rings inspected and cleared fitted refitting.

Piston clearance.

		Cylinder 1	Cylinder 2	Cylinder 3	Cylinder 4
(A)	Largest bore diameter ( From the chart above )	78.047	78.048	78.045	78.047
(B)	Piston skirt diameter ( From page 4 )	78.097	78.096	78.095	78.097
	Piston to cylinder clearance ( A - B )	0.05	0.049	0.05	0.05
	ok/fail	Ok	Ok	Ok	Ok

above is the block showing the piston bores which were measured diameter on 3 points with bore guage and venier calipers to check for distortion.subtracting the diameter of bores minus piston diameter gave figure for pistons clearance.all was with in specs and was cleared for reassembling.

Cylinder bore measurement.

		Cylinder 1	Cylinder 2	Cylinder 3	Cylinder 4
(1)	First measurement (direction x )	78.097	78.096	78.095	78.097
	First measurement ( direction y )	78.096	78.096	78.096	78.097
(2)	Second measurement ( x )	78.096	78.096	78.096	78.096
	Second measurement ( y )	78.096	78.096	78.095	78.097
(3)	Third measurement ( x )	78.096	78.096	78.095	78.097
	Third measurement ( y )	78.096	78.095	78.095	78.096
	Amount of taper (subtract third measurement from first measurement)	0.001	0.001	0.001	0.001
	Amount of ovality (subtract (x) measurement from (y) measurement)	0.001	0.001	0.001	0.001
	ok/fail	Ok	Ok	Ok	Ok

	Top ring end clearance
	Specification mm
	0.15 – 0.30	OK.	fail.
Cyl 1	broken	ok
Cyl 2	0.30mm	ok
Cyl 3	0.30mm	ok
Cyl 4	0.30mm	ok

check for damage on machined surface of block but none was picked up

	Cracks	Corrosion	Damage
Block face	None	No	no
Front face	None	No	No
Rear face	None	No	No
Water jackets	None	No	No
Exterior surfaces	None	No	no

Also checked shell bearing and refitted them.

main bearings oil clearance was within specs.

Checking the big end bearing clearances.

Place a strip of plasti-gauge across the connecting rod journal.

Fit the connecting rod cap with the bearing shell and torque to the manufacturer’s specification.

Remove the cap and measure the widest part of the plasti-gauge and record in the table below.

Lubricate the rod journal and the bearing shells and re-torque the cap to the rod.

Ensure the crankshaft turns freely.

Repeat these steps for all the other piston assemblies and record the big end journal oil clearances below.

Specification	0.024 – 0.042 mm( 0.08 mm max)
	1	2	3	4
Oil clearance (actual)	0.05	0.05	0.025	0.05
Ok/fail	Ok	Ok	Ok	Ok

Check the connecting rod end play, using a feeler gauge

Specification	0.30mm
	1	2	3	4
Con-rod end play (actual)	0.25mm	0.27mm	0.27mm	0.28mm
Ok/fail	Ok	Ok	Ok	Ok

i reassembled the engine block and tightend the bolts to the specifed torque and fittted the cylinder head onto the block to torque given

Component	Torque specification
Bearing caps	54 – 59 Nm
Connecting rods caps	35 Nm
Rear cover	8 – 11 Nm
End plate	8 – 11 Nm
Oil pump	19 – 26 Nm
Oil strainer	8 – 11 Nm
Oil pan	8 – 11 Nm

.i did the cam-timing and the lecturer approved of the work done

(the table were taken from the worksheet of the the practical 4843 short engine block)

fuel injectors

on car


used a multimeter to measure the resistance for the injectors against the given resistance spec. of the injectors
and pulsing/voltage at idle and when gently reved
also used a multi meter to measure the duty cycle of the injectors which was 100%
also used a logic probe  to measure injectors' pulsing,off the connection
from/to the ECU.


Resistance: 16.5

 Injector #1 …16.2…………….. Ω

Injector #2 …16.5…………….. Ω

Injector #3 …16.5…………….. Ω

Injector #4 …16.2…………….. Ω

I used the logic probe, connected to the ECU's connection to the injectors. I started the engine and the light was pulsing. When the engine was rev'd up the flickering was faster.this is because when the engines reving there alternator charges the battery with a bigger charge so the flickering is in response to the increased voltage.

I did the same test this time with a voltmeter. the red lead was on the injectors and the black lead was grounded. When engine was started the voltage was 14.2 V

When reving the voltage was 13.35 V. The increase is also attributed to battery charge increase as the injectors put out more fuel. As this a test of the fuel injectors an increase in voltage would then indicate that the injectors are working well.

Measuring Duty cycle: set the multi meter to dutycycle. When engine was started, the duty cycle was 100.5%.  Reving the engine the duty cycle was 100.3%

above,checking resistance of the fuel injectors.remove injectors caps and measure on the pins

average resistance of 16.5 ohms

injectors voltage 14.33 V at idle and 13.45 V at gentle rev

checking the duty cycle of the injectors:100%