How many times a minute

[simmitc]

Take a standard 4-stroke A-series engine running at 4,000 rpm. How many times a minute does each cylinder fire? It's a simple calculation, and I have my own answer, just looking for reassurance that I haven't missed anything obvious, so all comments answers and arguments welcome. Thanks.

[rayofleamington]

ignoring the number of cylinders as you want an answer for each cylinder firing.

4000rpm = 4000 times the piston rises up to TDC every minute
As it's a 4 stroke half of these are compression strokes and half are venting,
So the number of firings will be 2000 per minute (= 33.3 times per second )