Visual Examination Cylinder Walls C-145 O-300

[MoonlightVFR]

I want to visually view the cylinder engine walls for rust

How do I accomplish this in a simple manner?

I have good average compression.

It has been 12 years since TCM introduced SB03-3 and required boroscope inspections. Have we learned anything?


After reading reviews on 10 video inspection scopes I don't have much trust in purchasing a new tool.

Is there a consensus on our forum?

Regards

[GAHorn]

...Is there a consensus on our forum?...

Is that a trick question?

The cheap video inspection tools I've seen offered by HF and Northern Tool are not much more than a camera and a dentist's mirror. Some of them, contrary to their advertisements, will not even fit into the spark plug hole.

A quality boroscope will show you the upper cylinders and the rust which often forms above the travel of the top compression-ring.... but, ...
my own experience with the recommendations of the TCM Field Representative was that such rust above the travel of the compression ring is not worth worrying about. Both IO-470's in my Baron were overhauled by TW Smith back in the 1970's and one of them had chrome cyls and one of them had steel. The airplane sat outdoors for several years in New Smyrna Beach, Florida without any operations whatsoever when I bought it. I took it to an ABS Service Clinic where the TCM rep inspected them with a boroscope. The steel cyls were quite rusted above the ring-travel and the chrome cyls showed none at all, as expected.
The TCM rep advised me to "fly 'em and enjoy 'em." That was back in 1995 and those engines are still operating on that airplane with the next owner, a Continental captain who bought it from me in 1999. He called me not long ago (we became friends) and they are both well beyond TBO by now, I'm sure.
The conclusion I drew from it was, rust above the ring travel is not of much concern. The rings clean off the area they use. It's rust down in the lower end of the engine which is probably more trouble.

[cessna170bdriver]

Check the forums at vaf.net and do a search on "borescope". Like any forum you'll have separate the wheat from the chaff, but there's a lot of good info. No need to sign up unless you want to add to the conversation.

[DaveF]

I like toys and tools, so I bought a cheap USB camera like this one. It's fun to use and actually makes a decent image of the areas it sees, but it's nowhere near as good as actual eyeballs.

Continental's SB is really aimed at diagnosing exhaust valve problems. The cheap borescope would work for seeing colors and uneven deposits on the valve.

What I like least about the borescope was that I had to click "OK to Install" on a piece of software from China!

[4583C]

Grady
Before Del hauled "the eternal project" to Arkansas my curiosity got the best of me and I went to Horrible Freight for one of their cheapo bore scopes not really expecting much. After charging the battery and pulling the top plugs I spent nearly two hours poking the camera into the cylinders and felt much better when I finished. The only rust I found was at the very top of the cylinder where it tapers out to the head. Hopefully I can post some pictures.[resizeimg][/resizeimg]

[LBPilot82]

So I know you would most likely be looking for rust and deposits on the valve seats... but what about oil in the cylinder? I noticed during my annual what I thought to be excessive oil in 2 of my cylinders (although I can't remember off hand which ones). Mechanic said not to worry since I had only flown a few hours in the previous month or two. So away I went over the next month or two and put about 20 hours on it only to pull the top plugs again and see the same thing. I guess the question is how much is too much? I suppose there was a tablespoon or so of oil. Cylinders are ECI steel with 250 hrs. Runs like a top and I've never noticed it to be a problem so I haven't put too much of my attention towards it.

[counsellj]

[quote="Aryana"]The oil is a normal phenomenon. Everyone put your cameras away and go fly. Bring it out only if there is an actual problem and you want to know if you have to pull the jug. I've had mine for a few years and it's come in handy, most of the time it was validating an already suspected bad cylinder.

Arayana or anyone else,

What causes this oil pooling? I assume it must seep in past the valve guides. Or with no compression, can it seep past the rings when the engine is shut down?

[DaveF]

Here's an interesting borescope.
http://www.circuitspecialists.com/aardv ... oC9kbw_wcB

[GAHorn]

...Arayana or anyone else,

What causes this oil pooling? I assume it must seep in past the valve guides. Or with no compression, can it seep past the rings when the engine is shut down?

Yes, oil in the rocker box drains down onto the valve stems/guides after shut-down and seeps past into the cylinder. It doesn't necessarily signify any serious problem.

[n2582d]

... there doesn't seem to be a provision for a 90 deg mirror.

From the website:

Hook, magnet, and mirror tip attachments included

They show a picture of these items in the bottom frame. Not sure if the mirror attachment would fit in a spark plug hole.