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...)

[mshac]

A smart, thoughtful pilot like yourself would benefit greatly from a recording engine monitor. Once you have one, you'll wonder how you ever flew without it.

[n86121]

The current best options seem to be:

JPI 790
Would fit nicely bottom of my avionics stack.
Maybe I unconsciously had it layed out that way...

Upside - 'Simple,' lowest installed cost ( I think)
Downside - A ton of wires from engines, but sufficient to do the trick.

The other option

Suite of EI CGR units to replace EVERYTHING
Two CGR 30P, one for each engine, replace MP and RPM
and a CGR30C where Shadin is, to replace everything else

The appeal to EI is a hub in each engine and minimal wiring from there to gauges.

Going through an extensive annual 'wallet-ectomy' this year,
and replacing the last window (front)
because it's not as nice as all the other ones which are new 'solar grade'

[GearUp]

Originally Posted by n86121

The current best options seem to be:

JPI 790
Would fit nicely bottom of my avionics stack.
Maybe I unconsciously had it layed out that way...

Upside - 'Simple,' lowest installed cost ( I think)
Downside - A ton of wires from engines, but sufficient to do the trick.

The other option

Suite of EI CGR units to replace EVERYTHING
Two CGR 30P, one for each engine, replace MP and RPM
and a CGR30C where Shadin is, to replace everything else

The appeal to EI is a hub in each engine and minimal wiring from there to gauges.

Going through an extensive annual 'wallet-ectomy' this year,
and replacing the last window (front)
because it's not as nice as all the other ones which are new 'solar grade'

Other than grossly exacerbating the "wallet-ectomy", is there another reason a pair of Garmin GI-275 EIS gauges didn't make your best options list to replace everything? They're at the top of my list, but now I'm worried I'm not smart or thoughtful enough.

[n86121]

Good catch! I handn't thought of those.
Looks like $8k for the two displays, plus install.

One for each engine.
Even handles 4 tanks.

Hmmm.
Interesting.....

I see an STC to install,
but do they officially replace need for existing fuel gauges?

[GearUp]

I think a pair of GI-275 EIS's would replace everything engine-related, including the fuel levels on at least four tanks, and be STC'd as primary-- even on our Skymasters according to the AML.