[Nezil]

As the thread title says, I replaced my plugs today with NGK 97506, based on the recommendation from Halim and Dzenan. I've heard other forum members say that they found no benefit in doing this, but I thought it worth a try given my lower quality fuel.

Interestingly, my stock plugs, which had done 4,530 miles when I took them out, appear to have some yellowing around the base of the insulator that I've seen be suggested as gasses getting pushed out of the combustion chamber. This seems far fetched to me, but the yellowing does appear to be coming from the base of the insulator and it's the same on every plug.

The gap on my stock plugs was 0.70mm (0.0275"). I'm not sure if this is to BMW spec or not, I've not checked, but it is quite a bit larger than the 0.50mm that I set my new plugs to.

Installation was pretty straight forward. Removing the foam at the back of the engine is a pain, but possible to do without ripping if you take your time and lift and squeeze it over things sticking up. The biggest issue I had was having the correct 3/8" extensions for the rear most plug. I have 3", 6" and 10" extensions, and of course the required universal joint. With the universal joint, the 3" was too low to get a ratchet or torque wrench attached, and with the 6" extension, it was hitting the under side of the bulkhead. I managed to turn the plug about a 1/4 turn with the 6", then unscrewed the plug the rest of the way by turning the extension by hand. Torquing the new plug was fine, but once done, I found it a real struggle to unclip the torque wrench from the extensions to get it out! I managed in the end but that was the hardest part; a 5" extension would have been ideal.

[425M2]

Good tips about the various extensions needed, I am going to be changing mine soon. Were you able to get that foam back in ok? Mine is out and I am dreading trying to get it back in.

Also, notice any difference at all? I assume it is just running smooth and done for peace of mind? No issue running these new 0.02 gapped plugs on stock or stage 1 cars?

[Nezil]

Originally Posted by 425M2

Good tips about the various extensions needed, I am going to be changing mine soon. Were you able to get that foam back in ok? Mine is out and I am dreading trying to get it back in.

I found that putting the foam in was easier than taking it out. The bulkhead is smooth, so I put my hand between the crap on the top of the engine and squeezed the foam against the top; it wasn't that difficult.

One thing I did do that might have helped was to not re-install the O2 connector bracket until after I'd got the foam back in. You have to remove this anyway to get to plugs 5 and 6, and it does get in the way a bit when you're putting the foam back in.

Also, notice any difference at all? I assume it is just running smooth and done for peace of mind? No issue running these new 0.02 gapped plugs on stock or stage 1 cars?

I'm not sure yet, but I think it does feel better. Unfortunately I went on holiday for nearly a month and came back and had to drive the car for a day with the stock down pipe before I got around to re-installing the FabSpeed Sport Cat. Then I waited a day and installed plugs so there were a lot of changes in a short space of time.

I've been struggling with fuel quality here in the Bay Area, and I'd hoped that cooler plugs might help with the octane issues I was having. Having said that, I've also moved to running an E20 mix of fuel now, with the BM3 Stage 2 91 AKI map, and I was getting pretty good results before I changed plugs.

I've gathered some datalogs with the new plugs and the same fuel mix and will do a comparison when I get a chance. I'm still struggling a bit with Jet Lag after my holiday though, and I'm therefore not finding the time right at the moment.

I don't think there is any issue running these plugs and gap on the stock map, but I'm not sure. Here in California, it's warm most of the year, and pretty hot in summer, so cooler plugs probably help a little when IATs are higher. I'm not sure what happens when your plugs are too cold or the gap is too small. Anyone?

[cookiesowns]

I left the foam out on mine. Let the injectors tick all day, they must be working right?

Am I correct you didn't remove the bulkhead and thus the strut cross bracing?

That sign of the plug yellowing seems to be heat.. now I know why people say the "M" plugs are known for cracking. I don't think they take to heat well ironically.

[MTWO]

I took my sound insulation off as well. Don’t care for the tick

[Nezil]

Originally Posted by cookiesowns

I left the foam out on mine. Let the injectors tick all day, they must be working right?

The foam wasn't that difficult to get out and put back in, so I did it.

Am I correct you didn't remove the bulkhead and thus the strut cross bracing?

Correct, no need. It's pretty tight in there, hence the info I posted about extensions being somewhat critical. If I were to do it again, and I'm sure I will at some point, I'd make sure I had a 4" or 5" extension this time.

[cecaa850]

Originally Posted by Nezil

The foam wasn't that difficult to get out and put back in, so I did it.

Correct, no need. It's pretty tight in there, hence the info I posted about extensions being somewhat critical. If I were to do it again, and I'm sure I will at some point, I'd make sure I had a 4" or 5" extension this time.

I haven't messed with my plugs. Would jacking the body up have given you any more room?

[cookiesowns]

Originally Posted by Nezil

The foam wasn't that difficult to get out and put back in, so I did it.

Correct, no need. It's pretty tight in there, hence the info I posted about extensions being somewhat critical. If I were to do it again, and I'm sure I will at some point, I'd make sure I had a 4" or 5" extension this time.

Ah... Yeah my torque wrench is a bit beefy, so it will be super tight getting to the last 2-3 plugs. So I'll probably just undo the bulkhead if I want to do a plug job ( already have the extra torque to yield bolts )

good to know it's possible to do without however!

[Nezil]

Originally Posted by cookiesowns

Ah... Yeah my torque wrench is a bit beefy, so it will be super tight getting to the last 2-3 plugs. So I'll probably just undo the bulkhead if I want to do a plug job ( already have the extra torque to yield bolts )

good to know it's possible to do without however!

Be careful if your torque wrench is beefy... I bought a new one just for this purpose because my more beefy 1/2" drive unit's lowest setting is 30 Nm. The plugs need only to be 27 Nm (I believe, don't quote me on that!), and I didn't trust my other torque wrench to be entirely accurate at just 30 Nm.

[cookiesowns]

Originally Posted by Nezil

Be careful if your torque wrench is beefy... I bought a new one just for this purpose because my more beefy 1/2" drive unit's lowest setting is 30 Nm. The plugs need only to be 27 Nm (I believe, don't quote me on that!), and I didn't trust my other torque wrench to be entirely accurate at just 30 Nm.

Beefy as in it's big. I have a full range of snap on tech angles calibrated fairly recently.

[Drop the hammer]

I had a rough idle at 28,000 kms, lived with it to 30,000 kms and ordered up these plugs per protuning freaks recommendations. I’m running bm3 stage 2 with Fabspeed sport cat and csf intercooler on pump 91 octane. Installation was easy, removed the two plastic pieces from either side, the middle plastic piece and the foam. Lots of room to hit every hole with long extensions. I did use a knuckle just above the 14mm 12pt spark plug socket as the coil holes do have a bit of an angle half way up. Anyways, the new plugs I had to gap to 20 thou, and idle now is perfectly smooth. Throttle Response feels better too, but that might be in my head, but it really does feel zippier.

[Drop the hammer]

I watched this video prior to starting, it helped a lot, however I added the knuckle extension to prevent binding within the coil hole.

[Drop the hammer]

Also with the knuckle you can work around the strut brace, I did not remove it. I was just in front of the brace for hole number 5. Hole 6 is wide open, no hinderance at all once the plastic is removed.