4 ms·

That's pretty strange. It's possible for a mis-shift to not skip timing, but to be high enough to float the valves momentarily and allow for a valve (or more)

by vesrah 9y ago

That's pretty strange. It's possible for a mis-shift to not skip timing, but to be high enough to float the valves momentarily and allow for a valve (or more) to kiss a piston. This can lead to a very minor bend in valves to cause an idle misfire, until the valve eventually fatigues and drops. Diagnosable through a leakdown. A foreign object through the intake tract would be a more likely case for a 0 gap plug, as it would basically require a broken piston or valve to otherwise close up the gap on the plug and you're not missing this. Either way, absolutely terrible on their behalf and a zero sense diagnosis.

mulmen 9y ago
None of that happened, the head and valves are fine. I never missed a shift. I cut my teeth driving grain trucks so I always heel-toe double clutch. That makes missed shifts highly unlikely as the shifter slips easily from gear to gear, assuming you’re pulling it into the correct gear. Also I’m not an idiot and I have never selected the wrong gate. BMW also puts heavy springs on the shifter to make it unlikely the incorrect gate is selected on accident. There is no internal engine damage as far as my mechanic can see. The dealer did also do an intake cleaning (allegedly) which involves media blasting the intake runners. It is possible there was FOD introduced at that time. I mentioned that to the dealer and they assured me that is “impossible”. The dealer did put about 35 miles on the car while they had it for new plugs, maybe they missed a shift but there’s no apparent damage to the engine. The plug damage appears to be a result of negligent installation. My most generous guess is they dropped it on the floor. I wouldn’t be surprised if they intentionally re-gapped it to cause a misfire but I have no evidence. When they told me I needed a new head I called around all the shops in the area that work on these cars. I asked them how this could happen and if they have seen it before. All the shops I talked to in the Seattle area said they have never had an N54 open. They've never seen engine damage on one and doubted the diagnosis. BMW Seattle was the only place that said they had seen this "several times". I think they just use this as a way to make a quick buck or their mechanics are so incompetent that they routinely grenade engines by installing spark plugs and cleaning intakes incorrectly. What I do know is that the people responsible should be nowhere near a car and probably not allowed outside without close adult supervision.

by vesrah 9y ago

mulmen 9y ago

None of that happened, the head and valves are fine. I never missed a shift. I cut my teeth driving grain trucks so I always heel-toe double clutch. That makes missed shifts highly unlikely as the shifter slips easily from gear to gear, assuming you’re pulling it into the correct gear. Also I’m not an idiot and I have never selected the wrong gate. BMW also puts heavy springs on the shifter to make it unlikely the incorrect gate is selected on accident. There is no internal engine damage as far as my mechanic can see. The dealer did also do an intake cleaning (allegedly) which involves media blasting the intake runners. It is possible there was FOD introduced at that time. I mentioned that to the dealer and they assured me that is “impossible”. The dealer did put about 35 miles on the car while they had it for new plugs, maybe they missed a shift but there’s no apparent damage to the engine. The plug damage appears to be a result of negligent installation. My most generous guess is they dropped it on the floor. I wouldn’t be surprised if they intentionally re-gapped it to cause a misfire but I have no evidence. When they told me I needed a new head I called around all the shops in the area that work on these cars. I asked them how this could happen and if they have seen it before. All the shops I talked to in the Seattle area said they have never had an N54 open. They've never seen engine damage on one and doubted the diagnosis. BMW Seattle was the only place that said they had seen this "several times". I think they just use this as a way to make a quick buck or their mechanics are so incompetent that they routinely grenade engines by installing spark plugs and cleaning intakes incorrectly. What I do know is that the people responsible should be nowhere near a car and probably not allowed outside without close adult supervision.