O-470 camshaft inspection

Rjw872Rjw872
in General Discussion

Does anyone know of a way to inspect a camshaft that is still installed in an O-470. I’ve heard that you can but a borescope down thru the oil fill tube and look or pull a rocker tube and look thru there. Does anyone have any experience or ideas on this. The plane I’m looking at hasn’t flow much over the past few years and I’m concerned about corrosion on the cam.

Comments

  • Scott ShererScott Sherer COO Forum Moderator

    Have you taken it to a shop with appropriate experience?

    Scott Sherer
    Wright Brothers Master Pilot, FAA Commercial Pilot
    Aviation Director, Cessna Owners Organization Forum Moderator and Cessna Owners Author.

    Need help? Let me know!

  • Paul NewPaul New

    I do this inspection often. Acutally, just did it yesterday while performing a pre-buy evaluation on a P210. Just take the oil filler cap off and put your borescope down through the port. Be careful while rotating the prop to get the crankshaft in a good postition that you don't crush your borescope. You can see one intake cam lobe (the wide one), one exhaust cam lobe and three followers. With a little effort you can look forward and aft to see some of the rest of the cam and lifters but it won't be illuminated well enough to get good quality images. I attached three of the images I tood yesterday so you can see the possibility. No mechanic needed. Just get a borescope and have at it.

    WIN_20240620_12_12_14_Pro.jpg
    WIN_20240620_12_11_00_Pro.jpg
    WIN_20240620_12_10_34_Pro.jpg


  • planewrenchplanewrench IA 48yr A&P DAL A/C Inspector

    NIce shots Paul.

    carl

    IA 47yr A&P DAL A/C Inspector 172n

  • BruceCFVVUBruceCFVVU

    Thanks Paul.

    I am going to do this on my 470U during my next oil change when i have my borescope out. I’m not sure what i might find but it may be interesting to do this every oil change to have a benchmark.

  • PlaneJane1PlaneJane1

    I was volunteering at OSH when this was posted, so sorry about the late reply.

    Could this also work on the O-300 in my 172?

  • JimH in CAJimH in CA

    I have a similar engine, a GO-300 , and the only way to access the cam area is to remove the crankcase vent fitting and snake the borescope around the crankshaft to view the cam below it.

    Continental cams are less prone to corrosion, since it is below the crank vs a Lycoming where the cam is near the top of the crankcase and is more likely to collect any water vapor condensation.

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