Rotax 912 Overhaul

[facthunter]

If it's been out in the weather at all or water over it, strip it enough to determine the extent of the possible corrosion. First place is bores remove heads and inspect accessory drive areas starter and magnetos. Two strokes in general and 912's are better survivors of neglect in this respect than just about any other types. Two strokes are oily all through so they are often OK.

 

. The top of the "normal" aircooled steel barrelled aero engine starts rusting in the bores and perhaps cam lobes in a short time and MUST have been inhibited as specified by the engine manufacturer or the Authority to be legally reinstalled.. New engines have a shelf life as well.. It's an aeroplane. Not a ride on lawnmower. Nev

 

 

[slb]

i have recently acquired an XT912 airborne trike , it was built in 2005 with a rotax 912 UL ser#4407101 installed. It has only accumulated 226hrs TTSN, it was last run some time in 2011, so it has been sitting idle for a while at a place well inland (like 2-3hrs drive north west of Melbourne where it is reasonably dry. however according to rotax it should have an overhaul, is there any alternative. Calendar time of 15 years runs out in 2019,

Rotax Line Maintenance Manual 05-10-00 (page 5) states that the maximum possible storage period of the engine is limited to 24 months.

 

and that is providing the preservation directives have been followed.

 

 

[rankamateur]

Rotax Line Maintenance Manual 05-10-00 (page 5) states that the maximum possible storage period of the engine is limited to 24 months.and that is providing the preservation directives have been followed.

And stored in original packaging. A bit hard to organise after installation!

 

 

[facthunter]

How dry the environment is might affect the airframe but the engine MAKES water from the products of combusting Hydrocarbons. The hydrogen part forms water with oxygen , and quite a lot of it. If the engine is not hot when shut down water will be inside the motor which together with  a lot of acidic by products is ready to cause instant rust and corrosion. Nikasil  is not plated on in the usual sense. It's fused into  the surface so it's more alloyed than a coating. All engines should be inhibited if they are left idle, unused for significant periods once they are out of the box and put into service.  Steel  (the worst) or cast iron bores will be rusting inside a week, if the motor is just run to put it in the hangar, without getting hot at all. Leaving OLD oil in the motor won't help either. but it needs something in the cylinders where the oil rings leave little surface oil to protect it. Nev

 

 

[Yenn]

Luck play a very big part in this scene. Many years ago I was unboxing bren carriers in the army. they had been built in Canada, test run, thenboxed and sent to England. No packaging of any sort and fuel in the tanks. Seven years later we took them out of the boxes,  looked them over, put in a new battery and some of them started  with little trouble. They didn't blow smoke and had plenty of power. Amazing when you think of the conditions they were in, very humid. Some of course needed fresh fuel, and new coolant hoses, but very little else. They were low tech flat head Ford V8s.

 

I have seen people fly Jab and Rotax engines that have sat for years with very little use and no trouble.

 

I wouldn't recommend a minimalist approach, but a good check of the bores and especially the camshaft would be essential. Have a good look for any signs of water getting into the oil passages. Any pale coloured blobs in any oiled area is a dead giveaway.

 

The time to overhaul is a good case of ass covering. In my opinion if you do a thorough inspection and find no traces of problems, it would be OK to run the engine, but give it a lot of hard full power running on the ground, before trying to fly it.