fuel pipes

[braceuself]

hi guys.ill kiss anyone(male or female)who can solve this mystery.as i was leaving for scotland my fuel pipe snapped.the metal one from the pump to the injector.anyway i had it replaced.did 1400 miles in it in a week and its happened again to same pipe.all the clamps are in place and its a 1.7 diesel.would going a bit too fast cause this? thanks in advance. richard.

[Oldiebut goodie]

If a clamp is missing or has been put in the wrong place it could quite easily be able to resonate at low frequencies (easily done with a diesel) and cause work hardening at any solid point leading to fracture. It would be best to ensure that the pipe is supported so that there is less unsupported pipe.( And make sure that there is nothing else attached to it like cables.) It may be worth making up a support (if possible) for the middle of the piece that fractures so that the frequency at which it will vibrate itself to death is changed to a higher one.
I have seen it happen to copper fuel lines in boats where you get fractures a lot quicker as there are usually only 4 rubber feet isolating the engine from the hull so vibrations occur a lot easier.
It's worth plucking the pipe like a guitar string with your thumb to see if it sets up any bad vibes! (that takes me back to the 60's ) I've just looked in Bentley- and I am sure that my 1.6 has more clips than they show (3), (it's late and it's raining so I won't go and look).

[braceuself]

thanks for that.getting a new pipe made up tomorrow and will check for vibration.i only have the two clamps on it so will see what i can do.i have some play in the gearbox mounting which probably doesnt help.thanks again. rich.

[Oldiebut goodie]

These are the 3 shown in Bentley - hard to see but one above each pair of injectors and one holding all 4 just after the pump.

[braceuself]

mine are the same.think it was all the shaking from the gearbox mounting being worn that caused it, and from pushing the van too hard.i know a lot wont believe it but ive had my van upto 84 mph on the flat.i did it on thurs with the window down and realised how much it was screaming.so 70 mph and under from now on.