Thank you, everybody! I am glad you like my efforts on the engine.
Ernie, the electric wires were made from thin copper wire (about 0.2mm) painted brown.
Justin, thank you for the heads up! I have noticed the problem and was going to write about it. However, I also tried it twice and it is possible to squeeze in both, the engine together with the oil tank to the closed fuselage. So I will not break the fuselage.