What is taper and ovality in the bore, how is it caused how do you check it? The wear of the cylinder bore. caused when the piston moves up and down the cylinder. If it is tapered you can measure the diameter in three places. The top, bottom and middle. When checking the ovality you have to measure the circumference of the bore. The bore will be oval instead of being round.
What is side clearance on a piston and how is it checked? The purpose of the piston ring is to close the gap that is under pressure that makes compression in the cylinder. It is the gap between the piston and the cylinder. Checking the side clearance for the piston: put the piston ring into the piston. Using a feeler gauge put it between the piston and cylinder.
How can you tell the difference between a inlet and exhaust vavle and why? The size of the valves are different. The inlet is larger than the exhaust. The inlet is used for the air/fuel mixture to go to the engine. The exhaust's use is to disguard the left over substances mostly burnt fuel/oil.
What sort of tempatures do the inlet and exhaust valves get upto?
Inlet Maximum: 250 degrees
Exhaust maxumim : 750 Degrees
What temperatures and speeds must the piston be able to cope with?
The handle rotations can reach 7500RPM so the piston needs to be able to hold tempretures up to 300 degrees.
Why do we have piston ring end gap clearance ? The piston ring needs to be able to expand when under heat. The end gap clearance allows this to happen.
What could the result be if the piston ring end gap is too small? The rings could bend or break, close the end gap, cause damage to the bore.
Why do aluminum cylinder heads usually have a steel shim (washer) between the valve spring and the cylinder head surface ? It will bring the tension of the spring up to spec because over time the valve loses tension.
What is meant by the terms S.I and C.I in a four stroke engine?
S.I : stands for Spark Ignition. The spark plug is used to ignite the air/fuel mixture.
C.I : Stands for Compression Ignition. Highly compressed hot air to ignite the fuel, air only is introduced into the combustion chamber at the top of the stroke, then the fuel is injected to the compressed air.
What is the purpose of the margin on the valve? Exhaust valves have a larger margin than the intake valves because they have more heat produced to them. The margins on a valve are to help with the heat because if the valve gets to hot it will burn.
What is the purpose of a core plug? they are used to remove sand from casting when the engine block is cast.
What is end float and run out on a crankshaft, hows is measured?
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