4 strokes of a 4 stroke engine

November 28, 2016

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If an engine can go for 10000 rpm’s before it wears out; a 4 stroke engine with 100 rpm will run for 100 minutes than the other 2 stroke engine which has a higher rpm of 500 & will run for only 20 minutes.
  • No extra addition of oil :- Only the moving parts need lubrication intermediately. No extra oil or lubricant is added to fuel.

    1. Complicated design :- A 4 stroke engine has complex valve mechanisms operated & controlled by gears & chain. Also there are many parts to worry about which makes it harder to troubleshoot.
    2. Less powerful :- As power gets delivered once every 2 rotations of crankshaft(4 strokes), hence 4 stroke is less powerful.
    3. Expensive :- A four stroke engine has much more parts than 2 stroke engine. So they often require repairs which leads to greater expense.


    1. Simple design & construction :- It doesn’t have valves. It simply has inlet & outlet ports which makes it simpler.
    2. More powerful :- In 2 stroke engine, every alternate stroke is power stroke unlike 4 stroked one in which power gets delivered once every 4 strokes. This gives a significant power boost. Also, the acceleration will be higher & power delivery will be uniform due to same reason.
    3. Position doesn’t matter :- 2 stroke engine can work in any position as lubrication is done through the means of fuel (as the fuel passes by through whole cylinder & crankcase).


    1. Less fuel efficiency :- For every alternate power stroke, fuel gets consumed every alternate stroke. This makes the engine less fuel efficient although it results in uniform power delivery.
    2. Oil addition could be expensive :- Two-stroke engines require a mix of oil in with the air-fuel mixture to lubricate the crankshaft, connecting rod and cylinder walls. These oils may empty your pockets.
    3. More pollution :- 2 stroke engine produces a lot of pollution. The combustion of oil added in the mixture creates a lot of smoke which leads to air pollution.
    4. Wastage of fuel :- Sometimes the fresh charge which is going to undergo combustion gets out along with the exhaust gases. This leads to wastage of fuel & also power delivery of the engine gets effected.
    5. Improper combustion :- The exhaust gases often get trapped inside the combustion chamber. This makes the fresh charge impure. Therefore maximum power doesn’t get delivered because of improper incomplete combustion.
    Source: mechstuff.com
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