ticking noise, worse when cold...rings?

[beetos]

Mate of mine was complaining about his 735i being very 'ticky'. I helped him adjust valve and all were set pretty well but we did them anyway. On restarting the car the loud ticking was still there, but seemed to diminish as the car warmed up. I initially through that the valvetrain was probably worn. Tried unplugging injectors one at a time just for kicks and when we unplugged #3, the ticking went away, like completely dissapeared. Did not do a compression test but every cylinder made the car run just as rough when it was unplugged, however, #3 completely stopped the ticking also.

I am thinking either piston slap or maybe rings??? Its definately not valve clearance. Exhaust manifold does not appear to have leaks or cracks. Its not really a slap kind of noise, very much metallic ticking like a top end noise. Car runs perfect otherwise, no smoke, oil consumption etc.

Advice would be appreciated.

[whiskychaser]

Tried unplugging injectors one at a time just for kicks and when we unplugged #3, the ticking went away, like completely dissapeared.

Noisy injector? Swap it to a different pot and see if the noise goes with it?

[beetos]

I was thinking that but I really dont think it is the injector, sounds definately louder and more metallic and is wors when warming up. Might swap them around just to make sure though.

[genphreak]

I was thinking that but I really dont think it is the injector, sounds definately louder and more metallic and is wors when warming up. Might swap them around just to make sure though.

Its worth a try... farout its horrible having any suspect internal part...

[beetos]

Tried pulling plug wires and the noise went away when pulling #3 so was not the injector. Had a look underneath and noticed the header bolt missing on #3, put one in and it only holds lightly as the threads appear to be stripped. Noise is much better so it could just be a header flange leak. Will have to wait till it cools off and see but think I may have found it. If it is, its amazing just how metallic it sounds.

[Ross]

The M30 uses a stud and nut. No prob with a bolt I suppose just make sure it's the right lenght.