Holy Moly!!

[SharkPilot]

First, some background:

A few weeks ago I had a backfire. Following that I could not get the car to run right. The problem turned out to be injectors that were failing.
I replaced all 16 injectors with Accel units that I got from JeffVette.

Got those all installed and everything put back together. The engine ran great, most of the time. The idle would be very smooth and low speed running was just beautiful. Sometimes the idle was rough and there was a misfire at low speed. Up high it ran great and really took off. The fuel economy was poor too, running about 2 mpg less than before the injectors.

Today I decided to change the plugs. As I pulled them out they all looked pretty nice but the gaps were a bit excessive. I was thinking that the plugs may be on the worn side. The have about 10,000 miles on them.
Then I got to number 8. When I got that out I found that the center electrode and insulator are gone. Yes... gone! It's broken off about 0.5" above the ground electrode. It didn't happen upon removel either as the fracture face is blackened. This did not just happen.
These are Bosch Platinum plugs so they're not dime store cheapies. Has anyone ever seen this before?? And an even larger question... What did it do to my engine??
One good thing I guess is the ground electrode isn't bent or deformed so nothing hit it and clobbered it.

Edit: I just turned the engine over (backward from the alt. bolt) and the engine turned smoothly through about 1 1/4 revolutions. I did hear a small noise but it sounded like something in the front like timing chains or something.

Do any of you guys have any suggestions??

Thanks, SharkPilot

[flyin ryan]

probably went out the exhaust without even blinking an eye. i'm not a Bosch fan to begin with so i'll leave it at that...

[SharkPilot]

Thanks for the comment Ryan. Learned opinons always help.

Today I took the broken plug into work with me. Several people looked at it and agreed that the borken piece would be long gone. So when I got home I put the last four plugs in and cranked it up.
Long story short... It runs fine and smooth. A short test drove showed that it's running better than it has for a while, even after the new injectors. So now I'm curious about how long that plug was broken in there. There's no way to know so I'll just move forward from here.

SharkPilot

[flyin ryan]

Originally Posted by SharkPilot

So now I'm curious about how long that plug was broken in there. There's no way to know so I'll just move forward from here.

SharkPilot

hard to tell, obviously. i spend a lot of time detailing plugs on my stuff i squeeze compression on (small cube Comp., Super Stock) & the odd time a piston will tag a plug. more often than not it never misses a beat . pull plugs & it's like what the hell happened here? surprising what the engine doesn't care about sometimes. glad things worked out. what plugs did you go with? same thing?

[SharkPilot]

Originally Posted by flyin ryan

what plugs did you go with? same thing?

I already had four new Bosch in the other bank. Since I was so anxious to hear it run and make sure that all was well I went ahead and put the rest of them in too. There may be a set of AC split-fires in there soon though. The broken Bosch has me worried. Of course, now that it's happened once it will probably never happen again. I always thought Bosch made good plugs as a lot of people swear by them.
One thing for sure... It sure looks weird to see a plug with no center electrode in there. It looks like a dark cavern in there.

What we don't do for our cars...

[WB9MCW]

Well SP I think you were lucky and all is well that ends well!

Glad you got to the bottom of it all and are up and running strong again!

[flyin ryan]

Originally Posted by WB9MCW

Glad you got to the bottom of it all and are up and running strong again!

Brians an expert on bottom ends .

[flyin ryan]

not the first time i've seen problems with the Bosch fine wire platinums. i don't (can't) trust them.

[bldavis11]

So what plugs do you use? NGK's?

[flyin ryan]

Yes. i was sponsored by NGK when i used to race proffesional moto/supercross & they always seemed to have their act together, although i was a lot younger & didn't know a lot i could see that much, when i started getting into engines i used NGK's, just out of loyalty. years later & 100's of engines out the door i'm still using them. IMO, they are a very sound, reliable plug. no flash & glam, just get it done. i can count on them. the more a guy learns the more he realizes there isn't any magic in plugs, among other things, i just want one i can count on.