losing the compression on AAN.

[popdemonic]

here's the story,my car recently had a stripping out spark plugs thread on #3 issue.
while awaiting the repair kit to be arrived,i totally forget and had my car out for
a short logfile. unfortunately,the spark plugs came off the hole under the boost.
i limped her home and removed the coil cover and found the spark plugs exploded and
destroyed the plug boot.















today,i started to re-thread the spark plugs with the insert.





[IMG][/IMG]

[IMG][/IMG]

the result worked a treat.i can get the new spark plugs in.once the engine fired up.i got a slightly lumpy idle.i started worrying if some missing solid pieces of spark plugs
fell off into the chamber and caused the valve seats damaged.




finally,i did the compression test and found the cylinder #3 got 105psi.the weired situation happened when i did the test on remaining cylinders from 1-2-4-5.I got all 170psi except the cylinder #2 got 105psi.i still have no idea what's going on.since it had no any issues on #2.2 months ago,i just replaced the headgasket and remember the compression test is identical on 5 pots.now the engine is taking a little more time on cranking.i know something went wrong inside the engine.i tried to pull out the dipstick,no leaking compression or any smoke came off.i wish my cylinder wall is still in great shape and not being scored.any ideas?i'm going to the leakdown test soon once i got the tools on hand.

[quattro-nick]

maybe you can see with a little camera through the sparkplug hole in the cylinder for
damages

[popdemonic]

i i forget to mention i did a wet compression test and the number reading higher from 105psi to 145psi.
theoretically said the rings or scored cylinder walls but i will do the leakdown test again.

[UrS4boy]

The importance of checking your 20VT spark plug torque

i i forget to mention i did a wet compression test and the number reading higher from 105psi to 145psi. theoretically said the rings or scored cylinder walls but i will do the leakdown test again.

Don't know what to say Pop. Obviously you needed an A1-sized fluorescent pink Post-it note on the steering wheel that said "DON'T DRIVE CAR. SPARK PLUG LOOSE"

I am very afraid/sad to think this but I imagine that because you did not get all of the shards of the very hard, very sharp, white ceramic out of the cylinder before you drove the engine again, the cylinder walls are scored and/or the piston rings are nicked. (that said, the damage might have been done right when the plug shattered).

The fact that the compression came up to 145 with the wet test supports the damaged ring/cylinder wall theory.

I am guessing that you will have to take the head off again and inspect the cylinder wall (try the bore scope fibre optic camera first though).

This is why I post about making sure that your plugs are torqued properly - to prevent this whole thing from happening. Sorry.

The importance of checking your spark plug torque:

http://forums.quattroworld.com/s4s6/msgs/3757.phtml

[220bhp]

Sorry, but as urs4 boy said ..Damage may already have happened You need to put a scope down to see what, if any, damage had been done.