Free engine analyzer - zero install

[n86121]

I have been flying without and engine analyzer for 27 years.

Sure, I also like pretty things that go blinkety blink.
I confess I HAVE been thinking about it.

I see too many people get hysterical about one egt probe being 10F 'too high'
C'mon. These sensors are sitting in the flame off a torch.

Savvy has a nice article pointing out all readings are just averages anyways.

SO

On a trip from DC to 'Flarida and back about a month ago.
About 20 mins after takeoff, a slight vibration.
Subsequently disappeared.

Doing some math in my head...
First, round off the arithmetic for my own convenience.
(Like leaving a nice rounded $10 tip for a $42.68 bill)

So, let's call it 2400 RPM to make the math easy.

2400 RPM = 40 RP(Second)
In a 4 stroke engine power comes from 1 out of 4 rotations,
no matter how many cylinders...

So each cylinder fires about 10 times per sec.

So a slight 10 hz vibration meant one cylinder (out of 24) was unhappy.

There was no 'morning sickness,'
Valves probably happy, sticking valve unlikely.
AND going directly into annual just after return anyways.

Borescope of all valves showed very happy little round pizzas.
Cleaned all injectors, all happy happy.

Did I just save myself $12k on an engine analyzer?

(The 790 appeals to me anyway...)