Stick&rudder
I have to totally disagree, the problem is when the copper seal leaks the rubber seals get damaged and the blow by results in the injector becoming jammed in by glass like deposits.
You can search Utube for " how not to remove a BMW injector" to see the sort of problems these things can give.
There is no thread on the injectors themselves, they are clamped down via a lever and an M7 stretch bolt. Incorrect torque on the bolt, damaged threads or re-use of the bolt can cause the bolt to fail and the injector to be propelled at high speed from its orifice.
Anyone who writes a head off trying to remove a stubborn one needs to find a new career.
I think it is highly unlikely that a properly installed injector would come out, contacts in the car business tell me that when one of these fails the biggest problem is getting the injector out of the head, it is not unknown to write the head off trying to remove the injector.
It is far more likely that part of the supply system to injectors failed.
This all being said I would like to know the truth of the matter rather than ( informed ) speculation.
How can a fuel injector work its way out? It is connected to the aluminum fuel line at the top and it can not turn. Also the thread is very long.
This is what the injectors look like. The fuel line and electric connector prevent them from turning.
The “local knowledge” is that this one was a fuel injector (1 of 4) working its way out of its threaded hole (thread stripped, perhaps) and damaging a high pressure fuel distribution pipe running behind it as it did so. As the pipe got damaged, the pressure dropped and the engine presumably failed at that point. The engine bay had a copious amount of fuel inside it, so with the hot turbo….
They don’t usually break when they run dry but they are really a bitch to prime once they have run dry. You need a lot of pressure downstream and a lot of time to get them working again. I once replaced a “broken” pump and only later on a testbed I realized that it was just an issue priming it.
Aviathor
You are quite correct, pump lubrication has been an issue in the past but these pumps should all have been returned to the factory long ago.
Like a lot of things with this engine experience has resulted in lots of changes to improve reliability.
The one thing that kills these pums is running them dry as the fuel provides all the lubrication, old GA habits die hard and turning off the fuel on this aircraft at the end of the day becomes a pump killer when the pilot who try’s to start the engine the next day forgets to turn on the fuel.
The pumps are very different from the Bosch car pumps because they have to be modified to run on Jet A1 that is not as good as Diesel fuel when it comes to lubricatinf the pump internal components.
From the BEAs report it is my understanding that there have been some Thielert engine failures following pump failures due to lack of lubrication. The pumps were subsequently modified.
As the discusstion between Lyco/Contis and Diesel is ongoing…. what are the hard facts in cost when replacing/overhaule (Lyco only) the Engine Avgas versus Diesel ?
Would wonder who much lets say a O360 versus a CD155 cost.
So, I could think to buy a Lyco C172 or C182 or a Robin and when engine is due change to Diesel ? what would be the difference in Price?
I understand this was indeed a total engine failure…
