Spark plug nerds and experts: how do these look? (high-resolution macro SLR photos)

[iPhoneEngineer]

Just pulled these today from my VT2-500 boosted S54. I replaced them with the same, but my first question: I've heard some recommend cooler temperature ranges for FI motors; what do you think?

The most concerning thing to me is plug #3. It appears to have oil on the threads, and the spark plug galley for only that plug has a strange-looking flat spot drilled into it which also appears to have some oil sitting in it. Why does only plug #3 have this difference?

Do the plugs speak of rich running or too high a heat temperature? I notice tiny whitish crystals on them which I have heard can indicate too high a temperature plug.

Photos below--first each plug 1-6, then a new plug for comparison, then a detail on plug 3, then a series of shots into the plug 3 galley showing the weird region containing some oil.

[thekurgan]

My guess is #3 was loose and not torqued to spec (overheated as a result) as well as the plug well grommet needs replacing. When was the last time the valve cover was removed, for say, a valve adjustment? Were those grommets re-used perhaps? The other plugs don't look too bad, actually. I'm surprised ESS didn't recommend a cooler plug or going to iridium.

[Beedub]

ess recommend the stock plugs........
if its good enough for them, its good enough for me...

your plugs seem to running well, lots of sooty black is to rich, your seems to indicate a good burn, if your AFRs are in the 11s and your plugs look this they do id be happy with that...

what were your AFRs @ WOT again??

[iPhoneEngineer]

Originally Posted by thekurgan

My guess is #3 was loose and not torqued to spec (overheated as a result) as well as the plug well grommet needs replacing. When was the last time the valve cover was removed, for say, a valve adjustment? Were those grommets re-used perhaps? The other plugs don't look too bad, actually. I'm surprised ESS didn't recommend a cooler plug or going to iridium.

The valve cover has not been removed during my ownership; not quite to 39k miles, so Inspection II hasn't been done yet.

What is the purpose of this "plug well" and its grommet? Why does only cylinder #3 have one?

Yeah, I read quite a bit online about it being standard practice for even low-boost S/C applications to use at least one temp range cooler plugs; I think perhaps ESS wants to keep the "this works great with completely stock/OEM everything else; totally bolt-on!" appeal. What are the characteristics of iridium plugs specifically that you think might be desirable for a VT2-500 S54?

[iPhoneEngineer]

Originally Posted by Beedub

what were your AFRs @ WOT again??

I need to actually extract the chart from the dyno data because it involves a few extra steps I haven't gone through yet, but when I saw it at the Dynapack event it was 11.5-12 IIRC. I have no real problems at WOT aside from low boost, but the mixture is definitely off in lower exhaust flow scenarios which have been causing misfires.

I'm in the process of procuring OEM Euro headers (probably CSL) though absolutely dreading doing another header replacement just 1-2 months after I put the AA headers in. Also information on how to handle sensor positioning when converting USDM to Euro is pretty hit-or-miss at best, lol, and means I couldn't do the entire job myself (3 new sensor bungs to weld in that the AA headers have integrated).

[Beedub]

Originally Posted by iPhoneEngineer

The valve cover has not been removed during my ownership; not quite to 39k miles, so Inspection II hasn't been done yet.

What is the purpose of this "plug well" and its grommet? Why does only cylinder #3 have one?

Yeah, I read quite a bit online about it being standard practice for even low-boost S/C applications to use at least one temp range cooler plugs; I think perhaps ESS wants to keep the "this works great with completely stock/OEM everything else; totally bolt-on!" appeal. What are the characteristics of iridium plugs specifically that you think might be desirable for a VT2-500 S54?

i just dont think its really needed imo..... All the ess cars are running stock plugs, honestly, ess could easil supply a cooler plug with the kits and charge accordingly, hell they could even make money by recommending certain plugs, i see no advantage to them saying stick with the stock plugs, stock plugs are clearly working well, your plugs are how many miles and years old and still look in great shape imo :-)

The v8 cars are running 650hp on stock plugs which i believe are basically the same as our ones, our 500hp isnt really stressing them, probably the same situation with the coils as well ;-)

i recently swapped my plugs at insp 2 @ 10,500 miles and tbh i noticed no difference in the way the kit behaves.

[thekurgan]

Originally Posted by iPhoneEngineer

The valve cover has not been removed during my ownership; not quite to 39k miles, so Inspection II hasn't been done yet.

What is the purpose of this "plug well" and its grommet? Why does only cylinder #3 have one?

Yeah, I read quite a bit online about it being standard practice for even low-boost S/C applications to use at least one temp range cooler plugs; I think perhaps ESS wants to keep the "this works great with completely stock/OEM everything else; totally bolt-on!" appeal. What are the characteristics of iridium plugs specifically that you think might be desirable for a VT2-500 S54?

All the cylinders have these gaskets (part #14), they seal off the oil from entering the plug wells. From the picture, it looks like one of them is leaking or wasn't replaced properly during inspection I (valve adjustment should have been performed at this inspection, requiring the cover removed and all gaskets/grommets replaced). As for the plugs, whatever ESS recommends is ok by me, as long as they're torqued properly. Loose plugs cause heat issues and they will also have an audible "ticking".

[Twisted Six]

If any of you FI guys have the chance to pull your heads and bench them...one thing that we turbo guys like to do is index several sets of plugs and mark their respective positions for future installation.

Having the plugs all sitting at the same cross-points to valves can make for very consistent burning and plug life.

The only plug that will show a difference then will be a starvation or overage from intake design.

[Finnegan]

Originally Posted by thekurgan

All the cylinders have these gaskets (part #14), they seal off the oil from entering the plug wells. From the picture, it looks like one of them is leaking or wasn't replaced properly during inspection I (valve adjustment should have been performed at this inspection, requiring the cover removed and all gaskets/grommets replaced). As for the plugs, whatever ESS recommends is ok by me, as long as they're torqued properly. Loose plugs cause heat issues and they will also have an audible "ticking".

Wow, good information here! The more I know about maintenance the more convinced I am unless you have a very very good shop (and even then) the job is not likely to be done right. Looks like the only way to make sure is to DIY.

[iPhoneEngineer]

Originally Posted by thekurgan

All the cylinders have these gaskets (part #14), they seal off the oil from entering the plug wells. From the picture, it looks like one of them is leaking or wasn't replaced properly during inspection I (valve adjustment should have been performed at this inspection, requiring the cover removed and all gaskets/grommets replaced). As for the plugs, whatever ESS recommends is ok by me, as long as they're torqued properly. Loose plugs cause heat issues and they will also have an audible "ticking".

Interesting, thanks for the information. I could have sworn that no other plug wells had this area visible with just the coils removed; I shined light down in them and even took macro photographs of another plug well that didn't appear to have one...

I will contact BMW to try to determine what work was recorded as performed during Inspection I. I didn't realize a valve adjustment was called for then as well. Beedub, how the heck did you get Inspection II done around just 10k miles?!

Sad to see that BMW is probably doing poor work on this job, as I have the extended maintenance package (which amusingly, I confirmed will still pay for the bulk of the Inspection II work since the S/C kit doesn't complicate the job).

[iPhoneEngineer]

Originally Posted by Dark Schnitzer

If any of you FI guys have the chance to pull your heads and bench them...one thing that we turbo guys like to do is index several sets of plugs and mark their respective positions for future installation.

Having the plugs all sitting at the same cross-points to valves can make for very consistent burning and plug life.

The only plug that will show a difference then will be a starvation or overage from intake design.

I was wondering about the plug orientation when doing the replacement...sounds like a good idea. You wouldn't really have to mark the head to just mark the plug and choose an orientation relative to the position of the intake and exhaust valves, right? Which orientation is optimal--the dual ground points pointing towards the valves, or perpendicular to them? (I would think the latter).

What do you mean by your last sentence?

[inTgr8r]

Originally Posted by Dark Schnitzer

If any of you FI guys have the chance to pull your heads and bench them...one thing that we turbo guys like to do is index several sets of plugs and mark their respective positions for future installation.

Having the plugs all sitting at the same cross-points to valves can make for very consistent burning and plug life.

The only plug that will show a difference then will be a starvation or overage from intake design.

Haven't heard of anyone doing indexing for quite some time.

[Beedub]

arhh i love this engine section... so much good info in here :-)

[thekurgan]

Originally Posted by inTgr8r

Haven't heard of anyone doing indexing for quite some time.

I wonder how the indexing would work on the plugs with the crush washers. For iron block engines, with the tapered design, I had a bag of these copper "washers" designed for a little extra twist to index. Not sure how beneficial it would be for the S54, but it's got a good geek factor.

[thekurgan]

Originally Posted by Finnegan

Wow, good information here! The more I know about maintenance the more convinced I am unless you have a very very good shop (and even then) the job is not likely to be done right. Looks like the only way to make sure is to DIY.

Especially the valve adjustments, easier on the Z chassis, by far, and you can use more precise feeler gauges than the techs are allowed to use.

[Twisted Six]

Originally Posted by iPhoneEngineer

I was wondering about the plug orientation when doing the replacement...sounds like a good idea. You wouldn't really have to mark the head to just mark the plug and choose an orientation relative to the position of the intake and exhaust valves, right? Which orientation is optimal--the dual ground points pointing towards the valves, or perpendicular to them? (I would think the latter).

What do you mean by your last sentence?

I'd also be inclined to think perpendicular.

Last sentence......a lean or rich plug anomaly could be an indicator that the intake manifold is staving air or receiving too much compared to other cylinders.

We consider these things when engineering a modded intake.

[Shipkiller]

Three years ago, when I pulled the Vanos off the Roadster (M54) to replace the internal Vanos O-rings, I replaced all the upper valve cover seals. All the seals came in one kit. It was so easy to change out, even a cave man could do it.

If you feel that you have a seal weeping or leaking, it really is an easy fix.

[iPhoneEngineer]

Originally Posted by Shipkiller

Three years ago, when I pulled the Vanos off the Roadster (M54) to replace the internal Vanos O-rings, I replaced all the upper valve cover seals. All the seals came in one kit. It was so easy to change out, even a cave man could do it.

If you feel that you have a seal weeping or leaking, it really is an easy fix.

Thanks for all your knowledgable advice, guys . I'm fairly new to the S54 (I know a lot more about the 7M-GTE).

Does anyone know the purpose of these seals? That is, why does that circular area even exist, milled out of the side of the plug well?