Fahrvegnugen and Matpoc,
I would be happy to send you a new nozzle nut. No problem. DO NOT use a a crow's foot wrench. Remove the injector and use a standard 15mm deep socket. If you are trying to tighten in place, maybe a line wrench might work.
When considering what exactly is causing the leak, it doesn't necessarily have to be the nut, but that is where I would start. One of the 'competitors' used to show a torque setting of 45 ft lbs, and we always knew that was wrong. I'm sure that went by the wayside long ago. That 30 degree turn does cure a lot of issues but not all issues.
Also, many years ago, we introduced people to how to seat an injector's crush washer. Sometimes it appears to be a leak from fueling at the nut when it's actually the seating of the crush washer. Bubbles are NOT loss of fuel, but escaping exhaust gasses.
So, when reseating injectors, there is the conception that each time you remove the crush washer, a new one has to go in. Not exactly so... A very experienced aircraft pilot explained 'copper crush gaskets', particularly one that was for a Cessna, I believe. The gasket in this particular aircraft fuel pump could be disassembled and reassembled 2-3x before it had to be discarded. There was a flange on the gasket to mark 1x, 2x usage. But this gasket, like anything on a plane, is expensive. Some resourceful mechanics (and for their own use) would heat the gasket till they glow red and quench it in water to return them to annealed state. It's the opposite of annealing with steel, which red-hot, you harden it; copper anneals when quenched in water from red-hot.
The crush washers can be annealed by heating them on a piece of baling wire. A propane torch is hot enough to accomplish this. When cherry red, dip them immediately into water.
Also, I'm sure we have all seen copper pots or plates that are hammered. The method of hammering or planishing, work hardens the copper. So, that is a technique we have applied for many years. Copper PUSHES poorly, but HAMMERS very well.
Start by annealing your crush washers. Understand, there is a limit to how many times we would suggest doing this...2X. Insert the washers, injectors and lines as normal. Tighten the injector hold down forks to 15 ft lbs. Using a 1/4" flat punch and a 1 lb hammer, make a 6-8" drop to hammer the injector's line nut into the crush washer. The first strike, you will feel a 'thud'. Retighten the hold down fork bolt to 15 ft lbs. The nut will now make an additional 1/6th of a turn. Strike the line's nozzle nut again; you will feel it bounce this time... retighten to 15 ft lbs. Repeat one last time...There will be no exhaust leaks now.
Fuel leaks at the nozzle nut can be deceptive. Use compressed air to blow all the fuel off of the injector until it is dry. Start the engine and watch carefully to see if the fuel is coming from the nozzle nut or the Injector line nut. We often have seen the fuel drip from the top nut. I'm not saying it's not the nozzle nut, but we've been fooled before and so can you be fooled. This is the reasoning...
Just because the injector, properly set, should reach in excess of 4500 psi, does not mean the nut needs to be 'gorilla tight'. Between the body of the nozzle and the injector is a ferrule contact, which should be 45 degrees. We have seen attempts to tighten that nozzle line nut to stop a leak go WAY out of bounds. The ferrule line force needed is probably no more than 20 ft lbs torque. But what we have seen such force applied, the ferrule in the line side is crushed into a 'top hat'. A flat spot is crushed into the line side of the ferrule. This becomes like a washer between the line ferrule and the injector ferrule. Now, in order to stop the ferrule from leaking, it is straight down force, rather than the wedge of the ferrule contact to seal the line-to-injector. I just fixed an abused line this week that was exactly like this. It is not all that uncommon. Understand, the ferrule contact is a very strong seal, where a small amount of straight contact force is compounded by the bevel between the line and the injector. If the line is damaged like that, either we have to grind flat off or the line ferrule or it has to be replaced. We can fix 'em or replace 'em.
There are rare occasions that the seal surface in the injector is also damaged. We fix that, too.
Check it out, Fahrvegnugen. We have a lot of study doing this stuff. That's for sure.
