Reddit reviews Mike Busch on Engines: What every aircraft owner needs to know about the design, operation, condition monitoring, maintenance and troubleshooting of piston aircraft engines

There is no limit, fly it as long as you want. I know a guy with a cherokee flying an o-320 with 4500 hours soh.

Edit: If you are going to be an owner and be involved in the maintenance (which you should be), buy this book asap https://www.amazon.com/Mike-Busch-Engines-maintenance-troubleshooting/dp/1718608950

I've done exactly one, but it exposed some issues with my plugs, so I'll be doing it more regularly (not every flight, probably, but periodically). Per Savvy:

> Also known as the "in-flight LOP mag check," the ignition stress test is the best way to evaluate the performance of your engine's ignition system. Every student pilot is taught to perform a mag check during the pre-flight engine run-up, but many pilots have never shut off a magneto in flight and are uncomfortable with the idea. That's a shame, because the in-flight ignition stress test is far more exacting and revealing of any ignition system problems than the usual run-up. The typical pre-flight mag check can detect only the grossest ignition system defects, while the in-flight stress test will reveal much more subtle ignition issues. ... [I]f your ignition system performance is marginal, it will show up during a lean (preferably LOP) in-flight test long before it becomes apparent in any other phase of operation. ... I recommend performing the ignition stress test on a regular basis - I do it on most every flight, generally at the end of the cruise phase just before starting my descent. It should always be performed any time any sort of engine anomaly is suspected.

https://www.savvyanalysis.com/articles/in-flight-diagnostics (Author: Mike Busch, A&P IA, airplane engine guru; this should be required reading IMHO)

My on-the-ground mag checks were fine, ~100 rpm drop on both mags, smooth, temp changes were normal. But the in-flight test revealed three of my eight spark plugs have drifted way out of spec (>5000K Ohms internal resistance), a problem that would have eventually grounded me on a run-up mag check - but I caught it well before it degraded to that point.

It absolutely will catch developing issues that aren't "visible" during the run-up check.

Mike Busch is the author of Manifesto, which is an easy read, but introduces the general aviation pilot to a whole new way of thinking about aircraft maintenance. Now he's come out with a 500-page ultimate guide to GA piston aircraft engines. I can't wait to read this and know everything a pilot should know about how to treat their engine and how to handle it when things go wrong.

https://www.amazon.com/Mike-Busch-Engines-maintenance-troubleshooting/dp/1718608950/

I'm really glad you brought this up because I'm about to pick up my IO-360 with a fresh major overhaul, and I've been researching it. Lycoming says "Continue break-in operation for 50 hours or until oil consumption stabilizes." Millenium/Superior says about the same thing, but leaves out the 50 hours and just says "till the rings have seated, oil consumption stabilizes, and cylinder head temperatures drop" This is a sign that the cylinders are broken in". At 100 hours with negligible oil consumption, you are there for sure. So, nice job!

Have you read Mike Busch's book Mike Busch on Engines? If not, you should. Really interesting and informative. Do you have a digital engine monitor installed?