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Broken Spark Plug Ceramic

Discussion pertaining to positive pressure E28s.
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Maddog
Posts: 191
Joined: Feb 12, 2006 12:00 PM
Location: Atlanta, GA

Broken Spark Plug Ceramic

Post by Maddog »

I beat my 533i today at 9 psi pretty hard trying to break something, and I did...heh...

I broke a spark plug ceramic on cylinder 5. The ceramic seperated somewhere up inside of the plug so that it slides freely on the electrode in the middle.

Here are some pictures of my plugs...
http://picasaweb.google.com/george.carstens/SparkPlugs

If you download the pictures and blow them up, you can see really nice detail. What do you guys think? Detonation or not?
Maddog
Posts: 191
Joined: Feb 12, 2006 12:00 PM
Location: Atlanta, GA

Post by Maddog »

I removed the broken ceramic and took pictures. If you zoom in on the picture on the link I posted, you can see the ceramic up close.

I guess its possible that the ceramic was damaged when the plugs were initially gapped, but i'd like to know if this is detonation at work.
Last edited by Maddog on Feb 27, 2008 8:12 PM, edited 1 time in total.
Kyle in NO
Posts: 17638
Joined: Feb 12, 2006 12:00 PM
Location: Nasty Orleans------> Batten-Rooehjch------>More Souther LA

Post by Kyle in NO »

Might just be a defective plug...are they a colder heat range than stock?
Maddog
Posts: 191
Joined: Feb 12, 2006 12:00 PM
Location: Atlanta, GA

Post by Maddog »

Two degrees colder Bosch Super.
W7DC
Jeremy
Beamter
Beamter
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Location: Connecticut

Post by Jeremy »

No pitting, looks alright. How many miles on those plugs?

Jeremy
Maddog
Posts: 191
Joined: Feb 12, 2006 12:00 PM
Location: Atlanta, GA

Post by Maddog »

Probably close to 5k with LOTS of retunes (working with latest megasquirt code development).
slave2school
Posts: 371
Joined: Aug 23, 2007 6:35 AM
Location: NS, Canada

Post by slave2school »

It may have been even dropped before you got it. I know the latest ceramic glow plugs are super sensitive to anything like that, so why not spark plugs.
///ARINUTS...
Posts: 425
Joined: Feb 12, 2006 12:00 PM

Post by ///ARINUTS... »

i've had the same thing happen on 2 full sets of Bosch plugs. Never with NGKs. I'll stick to NGKs.
Maddog
Posts: 191
Joined: Feb 12, 2006 12:00 PM
Location: Atlanta, GA

Post by Maddog »

Anyone have the part number for 2 degrees colder?
///ARINUTS...
Posts: 425
Joined: Feb 12, 2006 12:00 PM

Post by ///ARINUTS... »

Maddog wrote:Anyone have the part number for 2 degrees colder?
for NGK? BPR7ES

I used the stock heat range ZGR5A with no issues up to 7psi.

you might want to try the BPR6ES first. its only 1 step colder.
BadM535i
Posts: 465
Joined: May 23, 2006 1:18 AM
Location: Dearborn, MI

Post by BadM535i »

I use Bosch W6DP0. Pricey but by far the best plugs I have ever used!
turbodan
Posts: 9246
Joined: Jan 09, 2007 10:19 PM

Post by turbodan »

I dont think its detonation. If its severe enough to break stuff, you'll see bits of aluminum on the ceramic. You'll hear it too unless you're running a very loud exhaust.

I dont know what to think about the NGK BPR7ES. I'm running them at the moment, but they're not as tall as the stock Bosch plugs. That means the spark happens farther from the center of the chamber, which could begin to induce detonation right on the fringe.
///ARINUTS...
Posts: 425
Joined: Feb 12, 2006 12:00 PM

Post by ///ARINUTS... »

I was fairly certain that it was boost alone( after a certain pressure ) that was blowing the spark plugs apart. They were W6DP. On some of the plugs, the ceramic portion was still intact, but separated from the main metal body of the plug, I would be able to spin it with my hand. Not Good, to say the least.

Turbo Dan, how much are you boosting? If it's under 1 bar, try the one step warmer plugs BPR6ES. Reason being, I used the the stock NGK ZGR5A plugs to 7-9psi with no ill effects.
Maddog
Posts: 191
Joined: Feb 12, 2006 12:00 PM
Location: Atlanta, GA

Post by Maddog »

I swapped in a set of BRP6ES plugs a couple of days ago and the engine is great again. Thanks for your help guys.
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