I beg to differ. How is it that several thousand 80 year old Model A cars are still running? While I'll grant you that their motors have been rebuilt many times since they rolled out of Henry's plant, they're hardly "worn out". Also, due to the lack of good roads back in their day, along with society's preference to use trains for long distances, ANY car that accumulated even a forth of that 100,000 miles was rare. Harvey
I think that given prevailing conditions that most flathead engines operated in, they survived exceedingly well. Many of the people who worked on them had the barest amount of tools,information,training,and experience.....yet they kept them running. Roads were dusty, filters were laughable or non existant compared to engines of today. The quality of oil was incomparable to the oils of today. Strapped for money, owners often reused the same oil after letting it sit so impurities could settle to the bottom of the barrel.........or used "bulk" rerefined oil. Gaskets were simplistic at best. The alloys used to manufacture components were good for the day, but again they are well below todays materials. Ignition systems were primitive, but easy to work on and fairly reliable for the needs of the day. All in all, the flathead was a pretty darn good engine for its time. With a little upgrade and modification to newer standards and using newer oils, the old flathead is basically bulletproof. The downside is that it is difficult to extract additional power at lower rpms due to the flatheads restrictive valve arrangement, and the limited power per pound could very well become dangerous to disasterous. Most people would agree that lighter is better in airplane engines. While the novelty of having a nostalgic engine powering ones plane may be appealing, I would advise very careful consideration and calculation if you decide to go that route. I don't think reliability is a concern, but power to weight and weight/balance might be.If you can verify that the engine is sufficient for your needs, then it would be pretty neat to hear a flathead purring overhead........