AUDI A8 D3 4.2 V8 BFM. CAR SWITCHED OFF WHILE DRIVING .
05-27-2014, 01:07 PM
#11
AudiWorld Senior Member
Yup, nothing funny about the look of that plug, never seen anything quite like it, hopefully never will ....... hope there is a good outcome for the OP
05-27-2014, 08:44 PM
#12
AudiWorld Super User
I saw it once...not pretty
when my dad had me pull him home the old fashioned way--with a rope. He said the 225 slant 6 in the Dodge just "gradually lost power." Motor turned but would't run. Pulled the plugs and found one melted down like that. Ran a compression check and got zero on same cylinder. Pulled head and found piston blown completely through to where I could literally see down to the rod bearing area of the crank, plus the wrist pin still hanging on to the remnants of the piston.
Yeah right, just gradually lost power dad?
Yeah right, just gradually lost power dad?
Last edited by MP4.2+6.0; 05-27-2014 at 08:47 PM.
05-28-2014, 05:36 PM
#13
AudiWorld Senior Member
Saw an engine like that
when my dad had me pull him home the old fashioned way--with a rope. He said the 225 slant 6 in the Dodge just "gradually lost power." Motor turned but would't run. Pulled the plugs and found one melted down like that. Ran a compression check and got zero on same cylinder. Pulled head and found piston blown completely through to where I could literally see down to the rod bearing area of the crank, plus the wrist pin still hanging on to the remnants of the piston.
Yeah right, just gradually lost power dad?
Yeah right, just gradually lost power dad?
Fresh plugs got it running. Just not very well or for very long. About that time a others friends Vega GT warped the head, the block, and threw a rod. The spark plugs looked better than this one. Overheating killed it also.
06-02-2014, 06:53 AM
#16
AudiWorld Super User
Bent valves obviously; timing belt...
You said in a prior post timing belt was good. I really doubt that; also look at tensioner, water pump and other pulleys etc. If belt still doesn't show issues, then it would probably be down to a thrown rod or broken piston specific to that cylinder.
In any case, at least the head needs to be pulled and valves replaced if head itself undamaged. But more likely, a motor rebuild alongside a decent guess that more valves will be bent, and on both sides. The most cost effective could well be a used engine swap--with a full belt job going in.
In any case, at least the head needs to be pulled and valves replaced if head itself undamaged. But more likely, a motor rebuild alongside a decent guess that more valves will be bent, and on both sides. The most cost effective could well be a used engine swap--with a full belt job going in.
06-02-2014, 02:10 PM
#17
AudiWorld Wiseguy
Ouch. Given that the plug is crushed as well as the bent valves indicates that the piston is no longer attached to the crank. Broken timing gear will bend valves but plug (snigger) should remain intact. My bet is on failed big end bolts or a snapped con-rod.
The engine must be making a terrible racket when cranking?
The engine must be making a terrible racket when cranking?
Last edited by dvs_dave; 06-02-2014 at 02:15 PM.
06-03-2014, 07:44 AM
#18
AudiWorld Super User
If only that cylinder valves are bent it is not timing belt. It is most likely that something got into cylinder. Piston is broken for sure. It sounds like engine replacement.
Roma is nice.
Roma is nice.
