Damaged Spark Plugs

Ram From Hell

Ram From Hell

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I'm finally getting TT in and tearing into the engine to sort out why it's running so poorly.

First step (and hard as hell with the turbos in the way) is pulling the plugs. Numbers 1, 3 and 10 all have broken ground electrodes. One actually has a broken ceramic insulator at the tip as well.

All I can think of is having possibly over-revved the engine, but I have no recollection of doing so the drive before it started running like crap.

I'm planning on getting some indexing washers (or equivalent) to help prevent this in the future.

Any thoughts on this?
 
Good luck! Good seeing you on here still :rock:
 
Ram From Hell said:
I'm finally getting TT in and tearing into the engine to sort out why it's running so poorly.

First step (and hard as hell with the turbos in the way) is pulling the plugs. Numbers 1, 3 and 10 all have broken ground electrodes. One actually has a broken ceramic insulator at the tip as well.

All I can think of is having possibly over-revved the engine, but I have no recollection of doing so the drive before it started running like crap.

I'm planning on getting some indexing washers (or equivalent) to help prevent this in the future.

Any thoughts on this?
Click to expand...

Isn't this engine around 8:1? If so, certainly wouldn't be an interference issue (like a piston dome).

With that out of the way (?), the only other time I've seen broken ceramics/electrodes that wasn't mechanical contact, was during severe detonation.
 
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I don't want to sound like a broken record but start with a compression and leak down tests. Now is definitely the time while the plugs are out. When I pulled #10 plug out of my old engine I found the gap closed with black gunk. That's when I knew it was all over but the crying.
For now don't worry about indexing the spark plugs. You will have a way easier time doing this when the heads come off. If everything was fine between the plugs, pistons & valves something had to change that caused the damage you described. Good luck.
 
Looks like you are experiencing detonation to me. It will do strange things to your plugs. Had it happen to me.
 
Post pics if the plugs. I agree sounds like detonation. Not enough fuel or too much timing. Could be wrong plugs altogether! What are they?
 
VENOMOUS1 RACING said:
Post pics if the plugs. I agree sounds like detonation. Not enough fuel or too much timing. Could be wrong plugs altogether! What are they?
Click to expand...

Don't recall the model, but they're NGKs.

After reading up, I'm inclined to believe that it's detonation as well. A couple of the pistons did show carbon accumulations.

I'll work from here. Up the octane, and consider a different heat range. One thing of note, I do remember that distribution in the factory intake isn't particularly uniform. At the ends of the manifold, it does tend to run lean. That's where the damage plugs are. ;)
 
Ram From Hell said:
Don't recall the model, but they're NGKs.

After reading up, I'm inclined to believe that it's detonation as well. A couple of the pistons did show carbon accumulations.

I'll work from here. Up the octane, and consider a different heat range. One thing of note, I do remember that distribution in the factory intake isn't particularly uniform. At the ends of the manifold, it does tend to run lean. That's where the damage plugs are. ;)
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Yes 1-2 seem to be most often hurt. ZFR6-11 NGK should be what's in there.
 
Just noticed you're on AEM. You should be able to enrichen front cylinders to avoid lean conditions. I believe you can control each injector Pulse width separately through AEM?
 
Might be some bits bouncing around in there! Compression test! Don't run it anymore until you determine the cause
 
I agree 100% on detonation. I'd get a boroscope and check out the cylinders with the lug issues. I'd bet there are signs of detonation on the pistons too. Hopefully all is well inside the motor. Time for a compression and leak down test.
 
Didn't have time to do a leak down, but did a compression test. All cylinders are between 160 and 170.

Also, I changed all of the O2's. They were looking pretty badly contaminated. The AFR gauges are reading much more responsively.

That said, the bank with two broken plugs is running quite a bit more lean than the other under every condition except while under acceleration. Then the AFR is nearly identical.

This leads me to believe that there may well be a couple of injectors that are not working well under low duty cycle. I'm going to pull them and have them gone through and flowed.
 
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