The engine arrived 25th of August 2023. It was ordered early 2018. A lot has happened since then. This engine previously weighed in at 259lbs with both alternators, starter, flywheel, EFII fuel system. The liquid cooling pipes, collection bottle and so on along with two water pumps are still to come.

The big box was needed to fit the Catto prop.

A bit of a look around…

The helicopter sump shown here will be replaced by a Sky dynamics cold air induction system.

We immediately noticed the cylinder base nuts were not ‘in safety’. That is, one thread or more showing at the top of the nut. It turns out that the AC-Aero cylinder bases are .6″ thick and the Lycoming .4″ hence the issue. Rather than replacing studs on every engine and for extra strength reasons, the designer produced some very special nuts that give more grip than the usual Lycoming 4 threads. A manufacturing glitch with these nuts added around a year to the engine delivery.

We have about 13 threads with up to 4 not engaged at the top. 9 threads vs 4 on a normal nut? I need to note this in the maintenance schedule, otherwise good to go.

The next issue is the helicopter induction pipes. These are not going to work with my cowls and radiators. I will have to get a new sump and a different install plan.

A very nice log book was included. The engine model is now LEIO-390 EXP I am assuming it means liquid, electronic ignition, Fuel injection and experimental category.

In the test cell the engine was doing OK.

The engine test run data is above. Maximum RPM by design is 3050 which might make around 270HP. We are calling this a 255HP engine based on the 2900RPM. What matters most to me is the torque as well as HP at economy cruise. It also needs to be safe from detonation for when I use Mogas and has been de-tuned slightly at the top end.