What spark plug do you guys recommend for my E53 4.8is?

[tmv]

NGK Iridium IX

[thrillcat]

Originally Posted by tmv

NGK Iridium IX

Put these in about 6 weeks ago.

[rogerkiu]

Thanks for comment!

How about ignition coil? Do you guys have any recommendation on ignition coil?

[StephenVA]

Are you having any miss fires on acceleration? The reason I ask is most coils last 100K. The OE ones are fine. See Penske parts for the OE number Penske Parts - Technical Diagrams & Parts Catalog

#1 *12131712219 *IGNITION COIL - BOSCH*(to 06/09) QTY 8 * $62.84
#1 *12137594938 *IGNITION COIL - BOSCH*(from 06/09) QTY 8 * $62.84 12137594938 was superseded by 12137594937.
#1 *12137594937 *IGNITION COIL - BOSCH*(from 06/09) QTY 8 * $64.71
#2 *12131437986 *LOCKING MECHANISM QTY 8 * $1.17

[rogerkiu]

Very informative! Due to the longer service interval, I think I will go for Lazer Iridium instead of Iridium IX.

By the way, as the Iridium IX has a tapered head, so the tightening touque for installation is differenct which should be much smaller than Lazer Iridium which has flat head, is it right? As the factory setting for tightening torque for spark plug is 30 NM, the torque should be reduced to 20 NM if I choose Iridium IX. Please let me know if my understanding is correct. Thanks for hlep!

[rogerkiu]

sorry that I think my understanding on the tapered head is wrong, all plugs are flat seat, so the tightening torque should be 30 nm for all type of the plugs. it is only talking about tapered electrode, not tapered seat.

[cn90]

No matter what the mfg says (they want to sell plugs), the IX easily lasts 100K.
However, I remove my IX plugs every 40K-50K just to verify and add anti-seize.

The IX lasts 100K in Honda engine. In fact, Honda owners manual say replace the IX plugs at 100K.

Tons of people in E39 forum use Iridium and love it, engine idles smoothly, gas mileage excellent.

[StephenVA]

Originally Posted by rogerkiu

sorry that I think my understanding on the tapered head is wrong, all plugs are flat seat, so the tightening torque should be 30 nm for all type of the plugs. it is only talking about tapered electrode, not tapered seat.

The tapered ground is the side terminal commonly referred to as the ground strap is not square at the end over top of the center of the plug. Seee picture below which shows the end of the ground strap having a slight taper at the end. The plug shell itself is threaded normally and when installed tighten up to 18Ft (+/-2) pounds using a torque wrench. I will research what it is in NT for you as you live in a metric world.

Video from a board member
BMW E53 Spark Plug Replacement DIY Guide - YouTube
https://www.youtube.com/watch?v=jUevDgIY5DU

Helpful?

[cn90]

Re NGK Iridium, I have seen this in my own cars, after some 40K-50K check interval, the gap is virtually unchanged.

For comparison purposes (my 1998 Volvo S70 with copper plugs), the copper starts to widen the gap at 25K or so, not too bad but it requires adjusting the gap for copper.

[Quicksilver]

Unless the plugs you originally had were flawed in some way and effected
your vehicles performance why not just put replace them with the same ones?
I suppose there are plugs that will provide better performance and longer life
but will it be a measurable difference? Hmmmm.+ Keep it simple.