I need to replace the fuel pipe on my TR7. I bought some 8mm pipe from a local plumber’s merchant – is this OK to use? The pipe was originally fitted in two sections, so I have replicated this, using an 8mm compression fitting to join the two halves. Originally it was fitted using a brake pipe fitting with flared ends to the pipe – this is no doubt stronger, but as my car has only a low-pressure carb fuel system, I thought this would be OK. There doesn’t seem to be any leaks.
I'm assuming you are referring to 8mm copper pipe, as opposed to a nylon/plastic alternative. If this is the case, it will be perfectly acceptable to use as a replacement for the fuel pipe and the low pressure will be adequately contained using the compression fittings. You need to ensure that the new pipe is secured firmly to prevent vibration fractures that might occur otherwise.