Q: Jean from South Africa here. I need some advice, if possible. I am in the process of rebuilding a one-of-a-kind high-wing pipe and fabric airplane and replacing the engine (an underpowered car engine) with a recently major overhauled Lycoming O-235-C1B engine.
The airframe flew with the car engine, but as this is seen as a major design change I need to treat the whole aircraft as a first flight and build up from there.
The engine has not been started since the overhaul. The engine needs a proper break-in to make sure the rings seat nicely.
My problem is how to properly run/break in the engine while it’s on the ground as the aircraft won’t be able to fly for long periods to achieve the proper power setting and time required.
I could send the engine to have an initial break-in on a test cell/bench with the supplied aluminum propeller.
I have been warned not to start the engine as this could start corrosion if I don’t run it often. Basically I have to get the plane ready to fly. I am in the process of building the custom exhaust, then the cowling. Then we are 95% complete. At this stage all controls, ignition, filtered air, fuel is done, so I could start her.
I’ve spent a lot of money on the project so far and don’t want to risk the “new engine” being ruined because of eagerness. What should I do?
Jean van Niekerk
A: Jean it’s so nice to hear from you and it looks like you’ve got an interesting project in the works here.
I’ll begin by telling you not to be in any hurry to start your engine.
I’ll assume, from your comment, that this engine has not been started since the completion of the overhaul. That being the case, my suggestion would be delaying the start-up of the engine until you are very close to completing the rest of the work and are getting close to flying the aircraft.
Starting the engine weeks or months before the aircraft can be flown may cause the engine to develop some internal corrosion as a result of running it now and then having it set idle.
I’d strongly recommend that when you get within a couple of weeks from completing everything else, and are preparing to fly the aircraft, then go ahead and start the engine and complete the ground run portion of the engine break-in.
The complete break-in instructions can be found in the Lycoming Service Instruction 1427C. Be certain to read all of the instructions set forth in this publication and you should have no trouble completing a proper engine break-in procedure, including both ground run and flight portions.
You’ll take notice that it is not a requirement to have an engine test club prop to conduct the break-in, but again, read all of the instructions carefully.
I wish you luck and all the best with your beautiful project.