NAM VET

Karl at RennsportKC, where my GT'3 motor has been on his workbench since last week, sent me some pictures of the problem. As you will recall, my engine developed a miss and check light a thousand miles from home, when i ran it up to about 7K on a merge, after filling with what was supposed to be 91 octane, down from my previous 93 gas. Hauled to RennsportKC, where Karl found the #3 plug to have lost the ceramic insulator and the center electrode. Compression and 'bore scope fine, new plugs and coils all around (I had these replaced on my 30K car with other things and welded pipes about 1,500 miles prior to the first incident.)

So continued on my way, and a hundred miles further, again a run up and again the miss/flutter and engine light, so back again to Karl.

So, had a rattle but no codes, so Karl dropped the engine, and took off the head, and today found the center electrode never left the cylinder and has damaged the piston, liner, and no doubt the valve and seat. He believes the head will be ok after a rebuild.

Cost, who knows, but in the vicinity of $10K, ,maybe more.

So it wasn't the engine, it was a defective new spark plug that caused all this to my motor.

In a few minutes I will tell my wife about this.

Wish me well,

all the best....

Saru385

glad to hear that the root cause was found. that sucks that the recently replaced spark plug is the culprit in all of this...

best of luck with the wife and a speedy recovery for the car.

audipwr1

Sorry to hear this, when you mentioned your electrode was missing this is what I feared.

I would replace all your spark plugs as well. Did someone try to gap the plugs? These new spark plugs can weaken and break if someone does that

ilko

Ugh. What spark plugs did you use? Where were they purchased from? Who installed them?

Spyerx

Oh man. So sorry to hear. But good news is issue is found a don 10k in scheme of a gt3 engine open is not bad. Question is what else "while in there...." Valve guides, bearings, etc.

No bigger question is what caused the ceramic to break. Could have been the bad fuel caused a bad knock? Or a bad plug? If a dealer installed those plugs I'd be filling them in on the adventure....

And no, these plugs should not be gapped, they come gapped (unlike my antique $2 plugs that were all way off out of box)

LateBraking

Depending on the company don't they come with a warranty? I know my Sachs stuff comes with a 1 year warranty, think Bosch does too, maybe file something with the manufacturer too? It's foreseeable that a defective spark plug can cause engine damage, it's inside the ending for Pete's sake.

Best of luck Nam, honestly that's not too bad in the grand scheme of things. I haven't talked about it but I ran up a bigger bill on my car recently (not engine related)....

CosmosMpower

Geez, sorry to hear. 10K is not a drop in the bucket even though it's cheap in GT3 land. Hope you get it back on the road soon.

blackbull

Time for a NA Beast rebuild!!!!!!

jonwb

I'm getting worried... Anyone hear from NV?

I know my wife would prob murder me. She's still new to the 'economy' of these cars.

surlynkid

I have begun measuring repair spend in terms of how many pro built spec miatas I could have bought. Wife does not want to know cost as long as her track cars are running.

NAM VET

After nearly forty years of marriage, I have learned how to reveal these sorts of financial surprises. Some years ago, I found the best way to inform my wife of a new firearm purchase is when she is in the shower. Not much she can do or say when she is soaking wet.

So, I waited until a similar moment, then told her that a defective sparkplug had damaged a cylinder and piston, and while it would be soon repaired and as good as new, it was going to be expensive. She really wasn't too upset, so I temporarily felt this expense wasn't too distressful for her.

But a little later, she told me to rent a UHaul trailer and meet her at her favorite furniture store. When I saw what was on the loading dock I had to go back for a bigger trailer. So loaded it full, and headed back to our other home in Upstate Charlotte.

Got thru it, and Karl at RennsportKC has been keeping me informed, says he has ordered a new piston and liner, and says while the valve and valve seats are banged up a bit from the electrode, the head is otherwise in good shape, and is being sent off to a Head Shop for renovation.

So waiting for our GT3 to be repaired, and ready for my thousand mile trip back home.

All the best....

Mike J

If its like any of the normal "warranties" they are only liable for a new spark plug!

I am glad the damage turned out to be less than it could have been, and it could have happened on any car. Sounds like it will be as good as new!

Given they have the heads off, any comments or measurements done on valve guide wear? It would be good to get some data points ...

Cheers,

Mike

jonwb

Why yes honey, I think the new couch and love seat and coffee table and lamps and rug and chairs look really great.

Glad to hear you survived!

Also glad to hear your car is getting closer to being back on the road.

hf1

Where did he/you believe the ceramic insulator and center electrode had gone?

Jamie_GT3

Definitely need to trace down the brand of sparks used... Any indication it was detonation that caused the spark plug to fail?