I inspected another A36 Bonanza recently, and one of the cylinder compressions was too low… lower than the minimum prescribed by Continental using the master orifice tool.
I had two options:
Option One: Remove the cylinder for repair or replacement.
Option Two: Make the exhaust valve seal better and improve the compression result in hopes of saving the cylinder from premature amputation.
I chose Option Two.
It was at least worth a try…
… and the result was stunning!
After lapping the valve in place and installing a new rotocoil, I ran the engine again and rechecked the compression.
It was 75/80!
The lowest cylinder on the engine was now the highest cylinder.
I also lapped the exhaust valve in cylinder #2, and that one improved from 49/80 to 63/80.
I recently inspected a Piper Saratoga, and I found the following condition on the right exhaust collector:
Earlier this week, I sent this photo to my email subscribers and asked if they would change this piece of exhaust if it was on their airplane. I received a huge response about this, with a large range of thoughts and opinions. Thanks to everyone who responded, as it really helped me think through the issue in a much more comprehensive way and I think you’ll find it helpful as well.
I read all the email responses in this episode of the podcast, and listed some lessons for us to learn from this exhaust story.
Today, I removed that exhaust collector and all three of the risers. When I looked on the inside, it became clear to me why it was bulged and deformed. The inside was eroded and thin in the area of the bulging, and I was glad we decided to change it.
I was reminded that when a piece of exhaust shows something like this on the outside, there is likely something happening on the inside as well. Here’s a close-up of the inside:
That’s evidence of many hours of exhaust gases rushing down on this area and going out the muffler.
It was definitely time to change this one. After reading all the responses and thinking about this all week, I’m convinced it’s much better to err on the safe side with exhaust systems.
Dave Ovad provided a link to an accident report where a Beech Debonair crashed because of a muffler failure and subsequent engine fire caused by the exhaust gases. It’s a startling reminder of how important it is to give special attention to exhaust systems. Here’s the link:
Dave, along with at least one or two others, also pointed out that it’s very important to fly with a good quality CO detector, to help prevent carbon monoxide poisoning.
Thanks so much to all of you who contributed to this episode by sharing your thoughts with me!
For more information about exhaust systems and carbon monoxide dangers, check out episode 035:
After a successful career in computers early in life, Carl Valeri decided years ago it was time to pursue his passion for aviation. Since that time, he’s been an airline pilot, flight instructor, aviation careers coach, mentor, Piper Cherokee pilot, and many other things.
Carl is well known as the host of two podcasts, the Aviation Careers Podcast, and the Stuck Mic AvCast. You can find him in both of those places:
In today’s episode, we talked about all kinds of fascinating things, including:
Carl’s background and how he got into aviation.
How he was hired years ago as an airline pilot, and furlowed the same year, in 2011.
How his struggle served to prepare him for what has become one of his greatest passions… “Helping people move forward with their aviation career.”
What the acronym “CAMEL” means to an airline pilot… I had never heard this before, and I thought it was really cool.
Carl’s current opportunity to lease and fly a Piper Cherokee… the 12th Cherokee to come off the line years ago.
The maintenance issues he’s encountered recently with the Cherokee.
And since this is the Airplane Owner Maintenance podcast, it’s only appropriate that we document this part with some pictures.
ISSUE #1: Smoke in the cockpit! Apparently somebody forgot to tighten an oil line!
The oil made a mess on the cowling. And upon closer examination, the source was identified – the rocker oil return line B-nut had come loose. When the oil dripped down on the hot exhaust, it produced smoke that made its way into the cockpit.
Solution and reminder: Always double check engine fluid lines and hoses, and apply torque putty to the B-nuts.
ISSUE #2: Fuel leak. Carl told us about a leak that showed up under the airplane on the left side. Listen to the episode to hear his advice about how to communicate with your A&P about issues like this.
It turned out the leak was from his “gascolator” or fuel strainer. Here are the parts from this ancient piece of technology… just like you might have seen on your grandpa’s tractor!
In this situation, Carl made the wise decision to upgrade to a “Steve’s Aircraft” gascolator, a much better design with increased reliability and ease of maintenance. Take a look:
ISSUE #3: Exhaust leak. Carl noticed some abnormal discoloration at the cowling seam.
It turned out there was a significant leak at one of the exhaust sleeve transitions in the engine compartment.
This situation is a little different than many Cherokees, since this particular engine was installed with an STC.
ISSUE #4: Electrical problem. With the benefit of 20/20 hindsight, Carl was able to recognize how the airplane had been showing some warning signs of this issue… be sure to listen to the audio to get the details.
What seemed like a complex problem in the beginning, turned out to be a blown fuse.
Sometimes the little things can make a big difference!
In spite of the maintenance challenges, Carl still loves to fly the Cherokee. I think one reason why is because he shares his love for aviation with others:
In telling about his aviation adventures in life, Carl is quick to acknowledge that, “I could never have done any of that without the help of others.” Now, he’s “paying it forward” in so many ways to help those who are coming behind him.
And finally, to finish up with a little humor: “Even an airline pilot who flies jets, recognizes there’s something missing in the following picture!
Carl, thank you very much for pushing all of us to keep moving forward and appropriately pursue our aviation dreams! We appreciate you, and I sure am glad flying still puts a smile on your face!
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