Engines

What is taper and ovality in the bore, how is it caused how do you check it?
Taper is a decrease in diameter from one end to the other.  for example when the piston hits against the bore continuesly changes the shape to oval. 



What is side clearance on a piston and how is it checked? 
Side clearance is the gap between the cylinder bore and the piston.

How can you tell the difference between a inlet and exhaust vavle and why?
The inlet valve is much bigger than the exhaust valve and that is because its job is to suck in as much air  as it can.



What sort of tempatures do the inlet and exhaust valves get upto?
The inlet temp is 250 degrees and exhaust is 750 degrees.

What temperatures and speeds must the piston be able to cope with?
The piston should be able to get up to 300 degrees and a speed of 30 metres per second.


Why do we have piston ring end gap clearance ?
The reason for this is so that the it allows carbon in so it can push the rings against the bore for better compression.



What could the result be if the piston ring end gap is too small?
The ends of the rings will touch when the engine heats up this can damage the cylinder walls.



Why do aluminum cylinder heads usually have a steel shim (washer) between the valve spring and the 
cylinder head surface ?
Thats because the aluminium is not strong enough on its own therefore by having the steel it will help not warn the head when it hits. 

What is meant by the terms S.I and C.I in a four stroke engine?
SPARK ignition and COMPRESSION ignition.  
What is the purpose of the margin on the valve?

Engines

How does a four stroke engine work? Name the cycles ,I want to now what the piston is doing and the vavles on each stroke?
The four stroke engine works by intake, compression, power, and exhaust.

Who and what year was the  four stroke engine invented?


The four stroke engine was invented by Nikolaus Otto in 1877.

What is the purpose of the crankshaft,camshaft,vavles collects(keepers),vavle sterm seals,head gasket,pistons,piston rings name them all, cambelt,flywheel?

CRANKSHAFT:  The purpose of the crankshaft is to drive the pistons.

CAMSHAFT: The camshaft job is to open and close the intake and exhaust valves.




























                                                                                                                                                        VALVES: The intake valve opens so that it can let air and fuel mixture into the combustion chamber and exhaust valve which cleans out all the used up gases from the cylinder.

VALVES STEM: The purpose of the valve stem is to open and admits gas to chamber. 

HEAD GASKET: The purpose of the gasket is to seal the cylinders to ensure maximum compression, avoid any leakage of coolant and to keep engine oil away from the cylinders.
















PISTON: The purpose of the piston is to transfer force from the expanding gas in the cylinder to the crankshaft.

PISTON RINGS NAMES: Compression rings, oil control rings, top compression rings.

CAMBELT: the cambelt is what controls the timing of the valves it is connected to the crankshaft and camshaft.


















FLYWHEEL: What the flywheel do is resists changes in speed and helps steady the rotation of the crank shaft.

























What is the bore and stroke. the stroke is when the engine travels from bottom dead centre to top dead centre. and the bore is where the piston goes and it lets it compress force 

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