Looking Back on the Engine Overhaul...

Well, Dan and I passed 2000-hr TBO on the engine at the end of 2011, and we proudly split those hours about 50:50 with our respective flying adventures over the past 6+ years. We decided to move ahead with the overhaul process now, rather then trying to eke out more hours. The engine was running reasonably well, but it had developed a number of small recurring issues that were increasing our repair expenditures and annual costs. The odds of an off-field landing and/or possible damage to our core value seemed higher in the coming year. I was thinking ahead about that flight to and from Lake Havasu across the desert and over the rugged terrain and mountains.
Our options - field overhaul (which had been performed on the last overhaul shortly before Dan bought the plane in 2004), factory overhaul, or factory remanufactured engine. A brand new engine was not an option. Since the engine had been previously field overhauled, we chose the factory remanuf route that would give us the best value - zero time engine to new specs. We signed on with Josh our IA A&P, and the engine was ordered mid-January. We got to fly until the new engine was delivered, and then it was to be a "quick" swap - out with the old, in with the new.

Then the fun began. The new engine arrived a bit early. It was time to say goodbye to our workhorse engine that had served us well. A 3-week turnaround was estimated, but lots of variables would be at play. The engine overhaul also results in other items getting overhauled or replaced - prop/governor, carburetor, new fluid-carrying hoses firewall forward, etc. We were also adding a spin-on oil filter adapter and moving to separate magnetos (non-dual, nonD). The work also revealed other needed fixes (e.g., Tanis heater probes, engine monitor probes). So there she hung with a worn red shop rag in her "nose" where the prop usually sits.

The engine mount got a closer scrutiny than it could during a regular annual with the engine in place. Ours was A-OK and ready to have the new engine swung into place. We're getting excited now. It was time to mount the new engine and to begin reconnecting everything. The work seemed to be progressing at a good rate, but not quite so fast. We discovered that going from D (dual) to nonD mags required some readjustments elsewhere like the prop governor and more.  The engine was delivered without the coveted spin-on oil filter adaptor that we (and our A&P) specified, and it resulted in considerable dickering around with Lycoming and the shops.  We won.  After about 3 weeks, we were ready for the first test run.

I wanted to be there for the first run up and ran out to the airport. They tugged it out on the ramp. Josh climbed in to the left seat. Another A&P stood ready with a fire extinguisher. I stood ready to snap photos. It cranks up easily, and Josh runs it up after some initial checks. The A&P and Josh swap places so that Josh can check the running engine for oil leaks and he finds a couple small ones. Unfortunately, he also discovered that the RPM reported on the tach seemed to be half the expected and not consistent with the sound of the engine. Another outcome of the D to nonD conversion, and the tach needed to be sent out for resetting.

A few days later, Josh signs it off, and Dan and I plan our first test flight - flying around the IOW pattern at 3500 ft for a couple hours and recording data on the engine - oil temps/pressures, CHTs, EGTs. All goes smoothly, and the engine sounds great...BUT...we soon discover that the oil pressure drops low below the green arc whenever we lean. This makes no sense to us, but we confirm it a couple of times. Otherwise, everything seems just fine. But leaning and oil pressure are not normally linked. ???

We flew a series of 5 test flights before resolving the oil pressure issue. Thinking that the oil pressure gauge was "blown", a test gauge was spliced into the line, but it showed the same phenomenon. The oil lines were adjusted and finally, resetting the lines at the oil cooler resolved it again. The weird thing is that the problem seemed illogical, and the fix was equally illogical.

But the problem was "fixed"...just in the nick of time for me to fly my scheduled trip to FL and Sun N Fun at the end of March. It was a perfect trip to break in the engine - flying at full throttle and at or below 5000 ft.  Let the fun begin...