Valveoscopy

[339A]

This post is an update to the earlier one I called Tool Deathmatch in which I discovered the "cheap" Chinese dental camera.

Well with 339A down for some maintenance (the nose wheel is getting the Anti Splat Bearing Mod, should have it back before LOE. Thanks Allan.) and with some spare time on my hands, I finally managed to perform a Valveoscopy on the H2AD. This engine has a total time of 1810 hours on it, of which 1125 belong to 339A. A compression check before starting the Valveoscopy showed the following: #1 78/80, #2 78/80, #3 78/80, & #4 75/80. #3 exhaust valve, which had been my problem child, still remains good!

With my Chinese Valvescope in hand, I began the surgical procedure and managed to snap the following pictures. What I'm interested in is educated comments/opinions on the internal condition of my engine. I know there are several knowledgeable Engine Gurus on here (you know who you are), and maybe we might all learn something. My internal engine experience is zero, but I didn't notice any cracks or serious discoloration in the valves that concerned me. Although #4 exhaust face looks like it has the measles, and there seems to be a lot of lead buildup on everything? Hopefully this might motivate others with high engine times to take a look and dig a little deeper.

I have created a Picasa Web album instead of trying to post all the pics on here. Here are a few of what I consider to be the more interesting ones.

#1 Exhaust Valve Face



#1 Exhaust Seat



#1 Top Plug Hole



#3 Exhaust Seat



#3 Intake Stem



#4 Exhaust Face looks like it has the Measles.



Thanks for looking, and hopefully some good will come out of this thread.

Regards,

[kevinh]

Cool! Btw - I just found what seems to be the same camera from the very reputable Chinese importer 'Deal Extreme' for $70. The URL is:

http://dx.com/p/usb-2-0-4-0-mp-50x-p...n-37296?item=4

[Vlad]

Scott I looked through your gallery with great interest. Thanks for sharing.

[tim2542]

I wonder if that is corrosion on the valve that appears as red specs?
Also can you tell us how you run the engine,ie LOP or ROP?
Thanks for the info, gotta get me one of those!
Tim

[miyu1975]

I don't know a lot about engines, but those are great pics and I see no cavities. May need to add a Chinese dental camera to my tool box.

[PeteP]

What camera are you using for the pictures. I looked at several and they all seem a bit large or bulky for internal cylinder pictures.

[erich weaver]

I believe folks are doing a bit of surgery and trimming down the neck of the dental cameras and then repairing them with heat shrink or equivalent so that they will fit the spark plug holes.

Erich

[339A]

Originally Posted by PeteP

What camera are you using for the pictures. I looked at several and they all seem a bit large or bulky for internal cylinder pictures.

Originally Posted by kevinh

Cool! Btw - I just found what seems to be the same camera from the very reputable Chinese importer 'Deal Extreme' for $70. The URL is:

http://dx.com/p/usb-2-0-4-0-mp-50x-p...n-37296?item=4

Looks like Kevin has found what appears to be the same one, but even cheaper! Nice going Kevin.

One note about the supplied software that I received. It really doesn't work. I found some "Freeware" on line called Debut Video Capture software. Be careful as they have a Professional version which they want money for. The free version seems to work fairly well. It's what I used to take all of these pics.

Originally Posted by tim2542

I wonder if that is corrosion on the valve that appears as red specs?
Also can you tell us how you run the engine,ie LOP or ROP?
Thanks for the info, gotta get me one of those!
Tim

I am running ROP. As of late I've been trying to be more aggressive with my leaning though. ROP would probably explain why it looks like lead buildup all over the place...? Certainly could be rust I suppose... just not sure.

Originally Posted by erich weaver

I believe folks are doing a bit of surgery and trimming down the neck of the dental cameras and then repairing them with heat shrink or equivalent so that they will fit the spark plug holes.

Erich

Erich is correct. That's what I did (you can see it in the link to my first post). You have to be very careful with the camera after the case is cut. I thought I had broke it this weekend when removing it from one of the spark plug holes... The LED block came loose and almost fell off. A little super glue on the side and amazingly it still worked! It's pretty delicate once you cut the case apart so be careful with it.

[BillL]

Cool pictures, the exhaust seats are showing their age. #4 appears to have low contact area, either due to pitting or deposits. Exhaust valves are cooled when they sit on the seats, between combustion cycles and with less contact for heat transfer they (it) will normalize at a higher temp. That might explain the spots, as they could be high temp corrosion, but hard to tell from the picture clarity. No idea how much life remains.

Decades ago, we mechanics would take a small coke bottle with water and dribble in the carb of car engines with lots of build up in the combustion chambers. It would clean them shiny ( like a leaking head gasket) and puke all the carbon/lead out the exhaust. It was certainly not an often used process, but quite effective. The engines ran much smoother at idle afterward due to more equal compression ratios and no pre-ingnition sources, but did nothing for valve seats or oil usage as would be expected. No engines were harmed in the process.

Maybe some guys with aviation engine experience could weigh in.

[RV10inOz]

Scott

The red spots are normal, all is good.

Your pictures make an excellent advertisement for running LOP.

Start using the APS method of climb leaning, leaning on the ground and in the cruise 10-20LOP at typically 65% or less and over the next hundred hours or so you will see things clean up.

If that was my engine I would be inclined to give it some high power and leaned into the "red box" time. For a few short bursts it will not do any damage, but it will clean it up a little.