339A
Well Known Member
Well this all came about because my #3 cylinder exhaust valve was leaking by again. A few years back I had the same problem. I lapped the exhaust valve and compression went back up. My last oil change showed a pretty significant drop down, about 70/80. Another check a couple weeks later had it at 65/80. This is getting somewhat serious now....
Lately I have been listening to Mike Busch "Savvy Aviator" series on the EAA website. He provides a lot of great information in his webinars. In the one "All About Cylinders", Mike talks about using an Intraoral Dental camera to inspect the cylinders. Well these things are pretty expensive and Scotty is pretty **** cheap. Also, I imagine it's hard to find a dentist who is willing to give one up. Alas, don't give up hope. The Chinese have made knock offs for just about everything out there. I came across a website called DH Gate and found a dental camera for $89.00 shipped direct from The Orient via China post...
Some notes about DH Gate: it appears to be some kind of Chinese Amazon from what I can tell. I was a bit leery ordering from this site but figured if I used Pay Pal and it didn't show up (they had a guarantee), well I'm out 90.00 bucks, but I might be able to get that back from Pay Pal. A couple weeks later it actually did show up as promised, via Chinese post, in my mail box.
I loaded the software.... Well let's just say the software is not the greatest. I think it is some kind of knockoff Dental software, however I did manage to make it work and figured out how to capture pictures with it. The instruction manual is written in the finest Chinglish now available. As an example from the troubleshooting section:
Item 3
trouble states: in the process of use, the image will be a little blurry
resolve methods: if you use it the first time, it belongs to natural reaction. It will be better later on
Item #4
trouble states: freezing images then appears dithering
resolve methods: the hand shakes when uses camera to capture image, when users are skillful for use products, the phenomena can be changed
Huh...???? I'm NOT making this up.
Oh well, it is from China after all.
Today I had the chance to give my new Chinese dental scope a try. First off (and I knew this might happen) it wouldn't fit into the spark plug hole. ****! No worries. I built an airplane, I'm sure I can modify this Chinese POS into something that will work. I'll just take it apart and see what's inside. This is what I came up with.
I opened it up, took it apart, cut the case on the band saw, and put it back together. A piece of green heat shrink to protect the circuit board and ICs. Voila!
I had re-lapped the #3 exhaust valve a couple weeks ago and wanted to check my compression to see if it had improved. After flying today and with my trusty Chinese dental scope in hand, it was time to find out. Good news, the #3 cylinder is back up to 78/80. Woo Hoo!! So let's try the camera and see how it works...
Now I called this post "Tool Deathmatch: Costco Borescope vs Chinese Oral Scope." What you haven't seen yet are the pictures I took with EAA Chapter 301's Costco borescope. I had borrowed this tool a couple months ago to try and get a look at the exhaust valve. The thing took terrible pictures. My grandson's Fisher Price camera works better than this! Honestly, this is the BEST picture I got of the exhaust valve. The rest of them were worse, if that's possible. You can sort of make out the shape of the valve.
Here are some pictures from today using the modified Chinese POS dental scope:
#3 Exhaust Valve. Look at the detail in the seat.
Another shot of the #3 exhaust valve
A pic of the #1 intake valve, just because.
Well, what can I say... looks like Chinese POS wins the match hands down! K.O. I'm pretty pleased with the results. For $89.00 dollars I've got a GOOD inspection tool for my engine. How long will it last, I have no idea.
Deb and I are planning a trip next week to San Diego to visit our son/daughter in-law and grandkids. I wanted to be sure that I didn't have an exhaust valve problem before we headed out over the Rocky pile. Now I feel much more comfortable about keeping this engine going. After all, this H2AD now has 1800 hours total time on it and 1100 of those are on 339A!
Regards,
Lately I have been listening to Mike Busch "Savvy Aviator" series on the EAA website. He provides a lot of great information in his webinars. In the one "All About Cylinders", Mike talks about using an Intraoral Dental camera to inspect the cylinders. Well these things are pretty expensive and Scotty is pretty **** cheap. Also, I imagine it's hard to find a dentist who is willing to give one up. Alas, don't give up hope. The Chinese have made knock offs for just about everything out there. I came across a website called DH Gate and found a dental camera for $89.00 shipped direct from The Orient via China post...
Some notes about DH Gate: it appears to be some kind of Chinese Amazon from what I can tell. I was a bit leery ordering from this site but figured if I used Pay Pal and it didn't show up (they had a guarantee), well I'm out 90.00 bucks, but I might be able to get that back from Pay Pal. A couple weeks later it actually did show up as promised, via Chinese post, in my mail box.
I loaded the software.... Well let's just say the software is not the greatest. I think it is some kind of knockoff Dental software, however I did manage to make it work and figured out how to capture pictures with it. The instruction manual is written in the finest Chinglish now available. As an example from the troubleshooting section:
Item 3
trouble states: in the process of use, the image will be a little blurry
resolve methods: if you use it the first time, it belongs to natural reaction. It will be better later on
Item #4
trouble states: freezing images then appears dithering
resolve methods: the hand shakes when uses camera to capture image, when users are skillful for use products, the phenomena can be changed
Huh...???? I'm NOT making this up.
Oh well, it is from China after all.
Today I had the chance to give my new Chinese dental scope a try. First off (and I knew this might happen) it wouldn't fit into the spark plug hole. ****! No worries. I built an airplane, I'm sure I can modify this Chinese POS into something that will work. I'll just take it apart and see what's inside. This is what I came up with.
I opened it up, took it apart, cut the case on the band saw, and put it back together. A piece of green heat shrink to protect the circuit board and ICs. Voila!
I had re-lapped the #3 exhaust valve a couple weeks ago and wanted to check my compression to see if it had improved. After flying today and with my trusty Chinese dental scope in hand, it was time to find out. Good news, the #3 cylinder is back up to 78/80. Woo Hoo!! So let's try the camera and see how it works...
Now I called this post "Tool Deathmatch: Costco Borescope vs Chinese Oral Scope." What you haven't seen yet are the pictures I took with EAA Chapter 301's Costco borescope. I had borrowed this tool a couple months ago to try and get a look at the exhaust valve. The thing took terrible pictures. My grandson's Fisher Price camera works better than this! Honestly, this is the BEST picture I got of the exhaust valve. The rest of them were worse, if that's possible. You can sort of make out the shape of the valve.
Here are some pictures from today using the modified Chinese POS dental scope:
#3 Exhaust Valve. Look at the detail in the seat.
Another shot of the #3 exhaust valve
A pic of the #1 intake valve, just because.
Well, what can I say... looks like Chinese POS wins the match hands down! K.O. I'm pretty pleased with the results. For $89.00 dollars I've got a GOOD inspection tool for my engine. How long will it last, I have no idea.
Deb and I are planning a trip next week to San Diego to visit our son/daughter in-law and grandkids. I wanted to be sure that I didn't have an exhaust valve problem before we headed out over the Rocky pile. Now I feel much more comfortable about keeping this engine going. After all, this H2AD now has 1800 hours total time on it and 1100 of those are on 339A!
Regards,
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