IC Engines

1.     What is the firing order of a four stroke engine? 
For most four cylinders inline firing order is 1-3-4-2 but each engine has a different firing order like 6cylinders its 1-5-3-6-2-4.




 2.What is the difference between a S.I and C.I engine?

(S.I) is a spark ignition engine that has a spark plug where is a (C.I) compression ignition engine does not have a spark plug as it ignites under high compression.

                                             
S.I engine piston                                                                           C.I engine piston

 3.Is there any difference between a S.I and C.I piston if so what?

The difference between the s.i and c.i is that the piston is shaped differentthe head of diesel pistons have a cup and the petrol pistons are quite flat.