meter conversions 2

 

Meter Unit Symbol Conversions Exercise 2

Practice converting from one unit of measurement to another. The value of the reading should stay the same, but it is expressed in another unit of measurement. (Example from K ohms to ohms, or millivolts to volts.)

1. 2.3 K ohms = ___2300___ ohms

2. 934 millivolts = ___0.934__ volts

3. 4.76 K ohms = ___4760______ ohms

4. 4 milliamps = __0.004___ amps

5. 24 K ohms = _24000__ ohms

6. 4.7 milliamps = _0.0047__ amps

7. 457 milliamps = _0.457 amps

8. 1014 millivolts = _1.014_ volts

9. 0.568 K ohms = __568__ ohms

10. 31 K ohms + 132 ohms = __31132_ ohms

11. 1500 ohms = ___1.5__ K ohms

12. 0.000225 amps = ___0.225_milliamps

13. 0.887 volts = ____887_ millivolts

14. 5.1 K volts = ___5100000__ millivolts

15. 121,955 ohms = ___121.955_ K ohms

16. 143,000 milliamps = ___143_mps

17. 125 millivolts + 11.875v = ___12_ volts

18. 310,000 ohms = __0.000000310_ M ohms

19. 0.00045 amps = ____0.45_ milliamps

20. 1,200 millivolts = ______1.2_ volts

meter conversion 1

 

Meter Unit Symbol Conversions Exercise 1

Practice representing a numeric value into different units of measurement. Notice the value remains the same, even though it is expressed using different symbols and the decimal place has moved to different positions.

Convert the following into it’s equivalent values:

Milli (m) Base Unit Kilo (K) Mega (M)

1. 1,700,000 mV ____1,700 V__ ___1.7 KV____ __0.0017MV__

2. _2,200,000mV___ ____2,200 V____ ____2.2 K____ __0.0022MV__________

3. _358000 mA__ 358A______ ___0.358KA______ __0.000358Ma______

4. _578,000mΩ__ _____578Ω______ ___0.578Ω ______ __.000578MΩ___

5. ___757000mA____ ____757A______ __0.757 KA__ _0.000757MA______

6. ____1300mV_____ ___1.3 V_____ ___0.0013KV_____ _0.0000013MV_____

7. _143,000mΩ____ ____143Ω___ ____0.143KΩ____ ___0.000143Ω________

8. _2,125,000,000mΩ __2,125,000Ω____ __2,125KΩ_______ ____2.125 MΩ__

9. __0.775 mA__ __0,000775A___0.000000775KA____0.000000000775MA____

10. _753mA_________ ___0.753 A_____0.000753KA__ 0.000000753KA________

11. 4,780,000mΩ_____ ___4,780Ω____ _4.78KΩ________ _0.00478MΩ_________

12. 3,520,000,000mA___3,520,000A_____ 3,520KA_______ ___3.52 MA__

13. __793 mV___ _0.793V____ ___0.000793KV___0.000000793MV___________

14. _3,473,000mΩ_ __3,473Ω_____ ___3.473_KΩ_ 0.003473MΩ______

15. 58,870,000,000mV _58,870,000V____ 58,870KV_______ ___58.87 MV_

16. _560,000mV_____ __560V________ ____0.56 KV__ 0.00056MV________

17. _246,782,300mΩ__ __246782.3Ω_ _246.7823KΩ_____ 0.2467823MΩ________

18. 340mΩ ____ ___0.34Ω___ __0.000 34 kΩ _______ ­­_0.00000034MΩ

yaaya!!

Mazda 323 engine head

dismantled an engine cylinder head, took out the camshaft, the valves and the valve springs,and measured the disassmbled components.




to disassemle the clynder head, i loosened the bolts holding the cam shafts. Marked on the holders is either "E" for intake or "I" for exhaust to indicate which side they go. to remove valves, i used a valve compressor.


 the first test is a visual inspection for any damage to the compenents. common damage is rusting,cracking warping or carbon build up. i found none and proceeded with the checks.


this picture is off the valves and springs when removed from the cylinder head.measured the components were within specs and were good for further use


Valve Spring Squareness(using set square to measure)

1. 0.508 0.508mm OK

2. 0.483 0.457mm OK

3. 0.076 0.178mm OK

4. 0.483 0.457mm OK

5. 0.508 0.584mm …....................................OK l

6. 0.762 0.711mm OK

7. 0.711 0.711mm OK

80.483 0.457mm OK

Valve spring free length:   

(Note: All springs in a set should have a free length within 1.5 mm of each other.)

1. 47mm 47.34 mm OK

2. 47.9mm 47.50mm OK

3. 47.6mm 47.46mm OK

4. 47.5mm 47.44mm OK

5. 47.5mm 47.60mm OK

6. 47.5mm 47.60mm OK

7. 47.5mm 47.55mm OK

8. 47.5mm 47.50mm OK

Valve spring installed height:

1. 39.52mm 39.56mm OK

2. 40mm 39.66mm OK

3. 39.66mm 39.37mm OK

4. 39.3mm 39.56mm OK

5. 40.32mm 39.52mm OK

6. 40.38mm 39.81mm OK

7. 39.81mm 40.94mm OK

8. 39.96mm 40.06mm OK

I check the spring tension or seat pressure which is checked on a valve spring pressure tester at the installed height obtained before. All measures should be in 5kilograms of each other

1. 18kg 17.6Kg OK z

2. 16.7kg 18.2Kg OK z

3. 17.8kg 18.1Kg OK z

4. 19.4kg 17.4Kg OK z

5. 15.6kg 18.1Kg OK z

6. 15.6kg 17.4Kg OK z

7. 17.3kg 14.3Kg OK z

8. 16kg 16.2Kg OK z

 the camshaft was measured for taper and ovality and passed specification.
the cam lobes were measured for wear, passed specification for further use

	Front	Middle
	1	2	3
Journal Ovality	26.043mm	26.043mm 26.043mm	26.043mm
Journal Taper	0	0 0	0
	OK ‚	OK ‚	OK ‚

	Front	Middle
	1	2	3
Journal Ovality	26.043mm	26.043mm 26.043mm	26.043mm
Journal Taper	0	0 0	0
	OK ‚	OK ‚	OK ‚

the results below are for the cam lobes and their lift.  the intake and exhaust lobes would have been the same at manufacture but due to wear from usage they change in measurements

1. Inlet:- (A)41.03mm - (B)33.0412mm = (Lift)7.988mm
2. (A)41.03mm - (B)33.041mm = 7.989mm 

Cylinder 1.

1. Exhaust:- (A)41.039mm - (B)33.001mm = (Lift)8.038mm
2. (A)41.038mm - (B)33.001mm = 8.037mm

1. Inlet:- (A)41.03mm - (B)33.043mm = (Lift)7.987mm
2. (A)41.04mm - (B)33.043mm = 7.997mm

Cylinder 2.

1. Exhaust:- (A)41.039mm - (B)33mm = (Lift)8.039mm
2. (A)41.037mm - (B)33mm = 8.037mm

1. Inlet:- (A)40.53mm - (B)33.045mm = (Lift)7.485mm
2. (A)40.53mm - (B)33.044mm = 7.486mm

Cylinder 3.

1. Exhaust:- (A)41.038mm - (B)33mm = (Lift)8.038mm
2. (A)41.039mm - (B)33mm = 8.039mm

1. Inlet:- (A)40.531mm - (B)33.043mm = (Lift)7.488mm
2. 40.53mm - (B)33.044mm = 7.486mm

Cylinder 4.

1. Exhaust:- (A)41.033mm - (B)33mm = (Lift)8.033mm
2. (A)41.036mm - (B)33mm = 8.036mm
   
   
   Checking camshaft bearing oil clearance (using plastigauge).
   
   
   
   
   1. Ensure the camshaft journal and bearing are clean.
   
   
   2. Position a strip of "Plastigauge" on top of the journal (in an axial direction).
   
   
   3. Place the camshaft caps in position and tighten to specified torque.
   
   
   4. Remove the camshaft cap and measure the oil clearance.
   
   
   Oil Clearance:
   
   

   	Journal 1	Journal 2	Journal 3	Journal 4	Journal 5
   Oil clearance	0.076	0.050	0.050	0.050	0.076

   
   
   
   
   
   
   
   
   
   
   From the results i determined the cam lobes and bearings were in good enough condition to be used again.

the cam shaft sprockets were visually inspected and were reassembled to within the torque specs.
 timing belt was relatively new so was clear for further use

  when removing and reassembling the valves,a valve compressor was used.separated the valves from
the springs and measured stems, length and clearance and when passed to within specifications where refitted
 onto cylinder head.below is the valve clearance results table

	Cylinder 1		Cylinder 2		Cylinder 3		Cylinder 4
Position A (i)	6.47mm	6.46mm	6.47mm	6.47mm	6.47mm	6.47mm	6.47mm
Position A (ii) At 90° to "A (i)"	6.42mm	6.47mm	6.47mm	6.47mm	6.47mm	6.46mm	6.47mm
Position B (I)	6.47mm	6.46mm	6.46mm	6.47mm	6.47mm	6.46mm	6.47mm
Position B (ii) At 90° to "B (i)"	6.42mm	6.46mm	6.47mm	6.46mm	6.47mm	6.46mm	6.47mm
Position C (i)	6.34mm	6.28mm	6.28mm	6.32mm	6.32mm	6.24mm	6.33mm
Position C (ii) At 90° to "C (i)"	6.41mm	6.34mm	6.34mm	6.02mm	6.28mm	6.32mm	6.29mm
	In	Ex	In	Ex	In	Ex	In
Average Reading	6.42mm	6.41mm	6.41mm	6.36mm	6.41mm	6.40mm	6.41mm

Cylinder	1	2	3	4
Inlet	Ok	Ok	Ok	Ok
Exhaust	Ok	Ok	Ok	ok
	OK fail  	OK fail  	OK fail  	OK fail  

 another shot illustrating valves when reassembling the valves and cotters(keepers) which was not an easy task without the specialised tools for it

the tutor provided us wuth torque specification for the Mazda engine which i referenced when reassembling the head components and the head onto the engines short block

Component	Torque specification
Cylinder head bolts	76 – 81 Nm
Water pump	19 – 26 Nm
Camshaft caps	11 – 14 Nm
Seal plate	8 – 11 Nm
Camshaft pulley bolt	49 – 61 Nm
Cylinder head cover	3- 4 Nm
Timing belt pulley	108 – 128 Nm
Idler Puller	37 – 52 Nm
Timing belt tensioner	37 – 52 Nm
Timing belt cover	8 – 11 Nm
Crankshaft pulley	12 – 17 Nm
Water Pump Pulley	8 – 11 Nm

Relays  :  use a low amperage circuit to switch on a higher amperage circuit. They are very common on vehicles, and although there are many types, they are very similar in how they work. 




5 pin relay









86 positve side of control with 85 as the negative. 30 is battery supply for the switched circuit and 87a is normally closed switch circuit,87 is the other switch

in the above picture the black is the negative pin 85,the bottom two pins are the positive powewrd 86 and 30,
top red clip is the switch when closed with 87a in the middle  and 87 pin to the light bulb with the green clip

Circuit Off                     Circuit On

86 0 V                           86: 12.09 V

85 V                               85 0 V

30 12.09mV                 30 12.8 V

87a 12.09V                  87a 0 V

87 0 V                          87 12.8V

first two pics show the relay used in class with an assigned switch to simulate headlights turning on and off.
last picture is of a four pin relay
..works similar to the five pin except the 5 pin has another switch circuit
(http://www.reuk.co.uk/Automotive-Relays.htm)


testing the relays


Resistance of circuits...86 to 85 88.2 Ω

                                  30 to 87a 0.2 Ω

                                   30 to 87 0.2 Ω

Control circuit that switches the points: __85__,86

Switched points that carry the higher amps: _30_, 87(87a)

If 12volts are used, the amperage would be: 12 V / 88.2 ohms = 0.136 A

in the drawing below the relay control is the switch for the light bulb.in this case it is off.

following it one of a two light bulb circuit, as the points are switched one of the two bulbs will be on,in this case the high beam because the point is closed