Thomas Moats wrote:
Thanks to you and Scott for replying.
Fairly much what Scott implied. While I am not mechanically challenged,
I don't get under hoods unless necessity dictates. I do not have the
empiricism to know if a slight timing change would allow a valve to make
an only slight contact with a piston where it would still run but would
cause performance damage (e.g. bent valve stem). I never heard any
sounds of damage.
I had stopped but after some rudimentary investigation. While it was
running with ample exuded black smoke (both exhausts), I heard at the
tailpipes the "phhht, phhht, phhht" sound of open valve(s), seemingly
only at the right bank. That with the OBD-II scanner timing readout led
me to believe the timing was changed. Until the misfire (#6 wire to #3
wire), the engine was running just fine (66K miles). No diagnostic codes
registered after I cleared the misfire code.
You can advance the timing to 30 degrees, the pistons will not hit the valves.
The mechanical timing between the crank and cam does not change.
Black smoke is an indication of a very rich mixture. A bent valve will not cause
that. The sound you hear is because of poor cylinder contribution ( you even
indicate the engine is not fully correct in running only better ) most likely
caused by an over rich condition. The fuel pressure may be way too high. When
changing wires you may have knocked off or left loose a connector. Also I hope
you did not just replace #6 wire, but all the wires and plugs. The problem is
most likely going to be where you have been ( replaced wire ), look there.
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