Broken spark plug electrodes

[jmsanders78]

Hi all,

I am now running some aftermarket cams in the M52TUB28 in my J prepared race car (BMW CCA CR), and at the end of the last race during the first race weekend (Summit Point) with the new setup I developed a severe misfire and power loss. I limped the car through 1.5 laps to finish the race and found misfire and ignition faults on cylinders 1 and 6. When looking at the coils and plugs to try to identify the cause, I found all electrodes were broken off of the #1 and #6 spark plugs and 3 of 4 electrodes broken off the #4 plug (picture order is 6->1 from top to bottom). In the closing laps I felt a stutter that felt like fuel starvation approaching the turn-in point for corner 3 at ~6000 RPM, but that isn't a spot where I would expect starvation in an E46. At that point the fuel level was low enough for the low fuel light to be on.

From what I can find online, this kind of spark plug damage can be caused by detonation due to a lean condition. I have experienced starvation a number of times when this car had stock cams but it never killed spark plugs. Could this be caused by fuel starvation or would tuning or some other kind of issue be more likely (the car was tuned with these cams)?

Thanks!

plugs.jpg

[Def]

With detonation, you'll usually see specks of aluminum on the spark plug that have been blown off the top of pistons. You'll usually see this pitting on the piston tops too.


Are you sure these are genuine spark plugs? I've seen a *HUGE* rash of knockoff NGK, Denso, and Bosch spark plugs from China in the past few years. To the point that almost every NGK spark plug listing on Amazon/eBay for iridiums/platinums is likely fake (cheaper price with Prime shipping than I can buy them at wholesale... huge red flag).

I even got some fakes off Rockauto before, so now I only order direct from a wholesaler who I know is getting them from NGK.

It's crazy knockoffs have gotten so prevalent it requires a huge amount of effort to ensure you get genuine products....


Not saying that's 100% your issue, but honestly, those plugs don't look like they've seen much detonation to me.

[jmsanders78]

With detonation, you'll usually see specks of aluminum on the spark plug that have been blown off the top of pistons. You'll usually see this pitting on the piston tops too.


Are you sure these are genuine spark plugs? I've seen a *HUGE* rash of knockoff NGK, Denso, and Bosch spark plugs from China in the past few years. To the point that almost every NGK spark plug listing on Amazon/eBay for iridiums/platinums is likely fake (cheaper price with Prime shipping than I can buy them at wholesale... huge red flag).

I even got some fakes off Rockauto before, so now I only order direct from a wholesaler who I know is getting them from NGK.

It's crazy knockoffs have gotten so prevalent it requires a huge amount of effort to ensure you get genuine products....


Not saying that's 100% your issue, but honestly, those plugs don't look like they've seen much detonation to me.

Interesting thought, thanks for bringing it up. I bought the plugs from Pelican a few years ago. Now I have a set of colder NGKs from Bimmerworld in the car so regardless of the last set, I feel good about the authenticity of this set.

[emoore924]

Take them to an NGK rep and see what they think. Could be the welds at the base of the electrode failed and the electrode went through the engine. They'll usually still fire, mostly, until the last electrode goes away.

As an aside, in my e36 m3, between (not) turn 2 and turn 3 was when we would experience fuel starvation until we went to a dual-pump setup.