From left: Arthur, Dave, Mervin, Dean (I got to work with these guys last Monday at Classic Aviation., when Dave had me lap the exhaust valves in cylinders 3 and 5.)

Scroll down for more info about this valve lapping adventure.


Diamond DA40 annual inspection – here are some squawks we discuss in this episode:

  • Electroair ignition leads.
  • Nose gear issues, including a missing elastomer element:
This is the elastomer pack for the nose gear. The small elastomer element in the yellow circle is the one that we replaced since the old one had split and fallen out of position. The hydraulic press was very helpful in compressing the stack to get the nut started. The end in the yellow circle goes on the bottom end when installed on the airplane, and the rod end bearing at the bottom of the photo is actually the top of the stack, and attaches to the engine mount at the firewall.
  • AmSafe seatbelts
  • RG24-15M aircraft battery
  • Alternator 500 hour brush inspection
  • Alternator aux. wire terminal loose
  • Aft door warning light inop.
  • Prop governor nuts under-torqued
  • Bolt dangling from the induction airbox
  • Oil leak caused by the engine driven fuel pump:
  • Engine baffling issues
  • Loose brake caliper bolts
  • Aluminum dust on prop spinner bulkheads:
  • Aft avionics fan inlet filter badly deteriorated and filthy:
  • Rudder cable tension low
  • Wiring and baffle rod under right side of engine

Now back to the valve lapping project with the Bonanza – here are the exhaust valves from cylinder 3 and cylinder 5… #3 compression improved from 60/80 to 62/80, and #5 compression improved from 55/80 to 69/80. The real test will be when we see the results after another 25, 50, and 100 hours of operation.

The #3 exhaust valve definitely has some irregularities; hopefully it will return to a normal appearance in several hours of operation after lapping and installing a new rotocoil.
The #5 exhaust valve looks quite healthy overall, with a very small questionable area at about the 1 o’clock position. We also lapped this one and installed a new rotocoil as a proactive measure.

By the way, these photos were taken with my new Vividia VA-400 borescope… I was very impressed with the photo resolution compared with my older borescope from a couple years ago.

Click here to check out the new Vividia VA-400 borescope.

There are various options, and if you want to display the images on your iPhone or iPad, I recommend the VA-400 WiFi Bundle #1: VA-400 and W01 wifi box (Model: VA-400W1)

When you purchase from Oasis Scientific and use the code “Dean” you will receive a 10% discount, and you’ll be supporting the podcast at the same time.


It was a great experience meeting Dave Ovad and working on his F33A Bonanza along with Mervin and Arthur.

It was also a pleasure to see Arthur’s P35 Bonanza that day:

Arthur has a really nice panel in his airplane as well… check it out:


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