I clicked to find out about the car for sale....as I have someone who has commissioned me in finding a nice RS6. Sad story here!
Somewhat ironic that in just this thread there are two people who have lost their engines to the "spitting spark plug syndrome". Furthermore, that myself made the DOA assessment and carried out the work to completion on one. It's a small world when it comes to RS6's.
It was pointed out the spark plug debris can and will (eventually) drop into the cylinder. Once that happens it's instant engine damage and a few moments later it's terminal. The cylinder wall becomes roughened, the rings can't seal, debris bounces around and may damage the piston and head or valves. It will take awhile for the plugs to become so loose for this to happen however. At the end the cyl. head will have all but lost all threads (as this one did). Tapping new threads wasn't a viable option either (a topic in itself). I have extensive pictures of said engine with my handy dandy high-tech boroscope. Not pretty, at, all.
And even if someone can hone/bore the block, then what? Buy all new pistons and rings, or just for one hole? I suppose it would sound kinda cool at idle with an extra lope perhaps. Or the compression ratio would be altered, perhaps causing Knock Sensors to either reduce or shutdown the related bank of cylinders. Professionally speaking no one in their right mind is going to fix one cylinder. And with the narrow bore spacing I'd question how much material is available. According to my machinist, who has been building race motors longer than most of us have been alive, it's a total gamble (and huge investment) to justify boring an aluminum block. Key concerns for me prior to the purchase of this car. I would pay handsomely to have an iron block option. Dang the weight issue, another 100-150lbs won't matter anyway (only 4-6% of the front axle load).
In my viewpoint it's crucial to replace plugs every 2-3yrs. Or 30K miles max. For those that are not pro techs, a good torque wrench is recommended (or simply having your hard working shop do it). This is one of the few cars I get out the overpriced digital Snap-On torque wrench that beeps and flashes it's disco lights at me (I have all 3: 1/4, 3/8, 1/2, plus an old Snap-On Torque Meter aka "torque dyno", including a 3/4" 550lb/ft 40lb monster and other fancy ones- even for tire valvestems)..... With that said, it's surprising how many loose or frozen plugs I've contended with, especially on late model cars. The plug may last 100K miles, but good luck removing them. So far in my experience it's the loose plugs that kill engines. And one of the most common DIY tasks that carries a huge risk if not done just so.
I see the car sold, congrats and sorry for your loss Will / Gator. I would have cried.
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Originally Posted by G2
