Look for the DC-7 engine info here

Why are piston engines so unreliable in airliners?

It is the 3rd post down. The person is so messed up with their math. Just wow! And no one caught it.

"an 18 cylinder radial engine requires approximately 54,000 ignition events per minute of flight "
And there is more.......

WOW that is one fast revving piston engine - and the 192 spark plugs in a Lancaster as well tho someone did pick that one.
AND the turbine engines were not as reliable even in the early/mid 1990s.
The RR RB211 engines in the 747SP at that stage had an in flight shutdown rate of one ever 1470 hours according to Boeing records of the time. The CF6-80 in the B767-300EREM on the other hand had an IFSD rate of one every 156,000 hours, partly because those were operating ETOPS (extended twin-engine Ops) with the related higher maintenance (EM) requirements.