Swapping in new spark plugs. Disconnect battery?

[Chris_D]

Might seem a daft question and it’s been so long since I did a plug swap that I’ve forgotten if it’s best practice to disconnect the battery before swapping new ones in?

I think the plugs are the original Bosch items and after 137k miles are probably way over-due a refresh

 

[Wildfire]

Don't think you need to unless someone is planning on trying to start the car whilst you're doing it.

 

[Lance]

No need to disconnect the battery.

 

[Chris_D]

OK thanks.

Got as far as removing the plugs and worringly, cylinder 3 had accrued some oil at the bottom of the well and the plug was covered in oil.


I'm assuming that it might be due to not re-tightening properly when I took them out to inspect them after I bought the car about 3 years ago when I had some engine issues.

I remember being absolutely paranoid about over-tightening and stripping the threads in the engine block, so maybe I didn't tighten down enough. Is there a torque spec for the plugs?

 

[Ewazix]

Plug Torque on the M54 should be 25nm / 18 ft lb according to a note I had from TIS data sheets

Oil around the plugs is probably coming from a leaky valve cover gasket around the plug tube seals. The Pelican parts how-to's are always worth checking

https://www.pelicanparts.com/BMW/techarticles/BMW-3-Series-E46/16-ENGINE-Tackling_Your_Valve_Cover/16-ENGINE-Tackling_Your_Valve_Cover.htm

 

[Chris_D]

Thx Ewazix, I just found it, yes 25Nm.

Hoping my vcg hasn’t started leaking as I only replaced it 2 years ago.
Might have seated badly around cyl 3.
:|

 

[firebobby]

Thx Ewazix, I just found it, yes 25Nm.

Hoping my vcg hasn’t started leaking as I only replaced it 2 years ago.
Might have seated badly around cyl 3.
:|

I hope you removed the foo foo pin before you changed the plugs Chris

 

[Chris_D]

Thx Ewazix, I just found it, yes 25Nm.

Hoping my vcg hasn’t started leaking as I only replaced it 2 years ago.
Might have seated badly around cyl 3.
:|

I hope you removed the foo foo pin before you changed the plugs Chris

You can just foo.. foo.. foook off Fred!
:lol:

 

[Sen07]

I’m looking to change my spark plugs in the coming weeks.
Could someone please shed some light on what the gap should be for the z4 e85 2.0i 2005. I will more than likely go with the NGK iridium plugs.
Im not seeing anything about the recommended gap in manual.

 

[Smartbear]

I’m looking to change my spark plugs in the coming weeks.
Could someone please shed some light on what the gap should be for the z4 e85 2.0i 2005. I will more than likely go with the NGK iridium plugs.
Im not seeing anything about the recommended gap in manual.

Plugs these days come ready to install & shouldn’t need any adjustments
Rob

 

[Sen07]

Yeah I did read this (I’ve not changed plugs before) but pretty sure I can manage it. I thought the pre set gap is only okay if set right for the engine from factory. So thought it’s worth checking