2004 Lincoln LS V6 3.0. 108k miles.
So last time I posted here I was asking about low compression on cylinder #1, link here: (Very Low Compression), and after running Engine Restore and Rislone Ring Seal through the engine for about 50 miles, the idle has smoothed out and there are no longer any misfiring codes, in fact there aren’t any trouble codes at all! (Hurrah).
Reading the last post (link above) may help with diagnosing this. . .
Accelerating to 2500 rpm and above before the motor is fully warmed up causes a nasty sound, almost like you can hear all the individual valve sounds amplified, or like the timing chain is chattering loudly at the pace of the engine. The sound disappears as the gas pedal is released, but it happens (albeit more quietly) even when the engine is warm. My timing chain is at 100k+ miles now, but the tensioners are brand new. Before piston #1 slapped a valve this sound was happening with the original cylinder head after I redid the timing of the engine, and after I replaced the cylinder head the sound still happens, so it can’t be rod knock or piston slap, right? Maybe inadequate oil supply? Worn timing chain and guides? Spark knock? I redid the timing in the first place because a while back bank 2 threw a code saying timing was over-retarded, and after resetting the timing this noise problem started which happened simultaneously when timing was thrown off and piston #1 hit the valve (in link posted above). I will be replacing the timing chains soon anyway because last time I heard this noise my timing was thrown off on bank 1 causing misfires and eventually piston #1 slapped an intake valve and destroyed the original cylinder head.
For simplicity here’s what happened in order:
- Bank 2 threw code saying over-retarded timing.
- I reset timing chains and weird chattering noise started happening under moderate/heavy acceleration when motor is cold (and slightly happens when warm).
- Eventually timing was thrown off on bank 1 at the same time as the chattering noise began causing misfires and piston #1 to hit intake valve.
- Replaced damaged cylinder head and fixed low compression on cylinder #1 as well as reset timing again.
- Engine still makes weird chattering noise under moderate/heavy acceleration.
- And so I’m afraid timing will be thrown off again and another valve or cylinder head will be destroyed. So my question is, does this sound like a worn down timing chain and guides?