Engine Capacity

Engine Capacity = Swept Volume = Engine Displacement

We use all of these terms interchangeably and they all mean the same thing

When we calculate the capacity of an engine it is simply the bore, stroke and number of cylinders calculation. The swept volume of a single cylinder is the cylindrical volume = stroke x pi x bore2 / 4

An engine with a bore = 25mm and a stroke = 50mm has a capacity of 24500mm3 and you need to divide this by 1000 to convert to cubic centimeters = 24.5cc

Our excel workshop calculation has a tab for engine calculations and has this all in a simple spreadsheet.

We can achieve the same engine displacement by changing the bore and stroke, this will result in the same engine capacity, but those engines will have different characteristics.

If the stroke is bigger than the bore we term this a long stroke engine, characteristically: slow revving, tall and with higher torque.

About Nigel 411 Articles
I've been making models since I was around 7 years old and using a lathe from the age of 11, a self taught engineer with a passion for making model engines.

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