Engine noise- stuck lifter?

[phrogs]

haha Not for me My tool control program is on point.

Originally Posted by WARP TEN

Lots of good advice here, but I would be remiss if I didn't once again post my idea for the strange ticking sound. --Bob

[HAWAIIZR-1]

Originally Posted by WARP TEN

Lots of good advice here, but I would be remiss if I didn't once again post my idea for the strange ticking sound. --Bob

😂

[WARP TEN]

Originally Posted by phrogs

haha Not for me My tool control program is on point.

Watch out Johnny--this soon could be you....Bob

[1991 Corvette ZR-1]

Just armchair quarterbacking the issue, but the rev to 3K rpm seemingly resolving the issue, to me, indicates an oil pressure or quality issue. The result is a ticking lifter or lifters. Does the actual drivability of the vehicle seem different? From a cruising perspective, or moderate acceleration, a failing coil pack will not allow you to maintain anything close to the performance you were familiar with before the issue developed. Unhappy ticking valvetrain will, it will just sound like a sewing machine from hell.

A bad or failing coil pack?s performance should not improve with increased demand in revolutions from air, fuel and now the significant increase in spark production demand from idle to 3K.

Furthermore, the heat generated from a cold idle time to a fully heat soaked motor from idling while diagnosing the issue should have an adverse impact on the failing coil capability to clear up when revved. You mentioned sludge on the distick, despite newer oil being changed in. If you can ohm the coil packs cold and hot and they check out, an oil change may be an easy option for next step.

With fresh oil, a few short drives SHOULD completely resolve the ticking lifter. If that is the case, something is in that pan that is compromising any oil put in over time and the valve train is not happy.

[Tim555]

Update on this. I checked the resistance of the coil in the affected cylinder. It was 21.3k ohms cold and 22k ohms hot. I did notice that I can hear a noise under the car as well, and can feel an exhaust leak where the header connects to the rest of the exhaust on this side. The sound seemed more substantial than an exhaust leak ticking, and I don?t know if that leak was there before I started hearing engine sounds.

The cylinder for the engine that I thought was making the noise seemed to be a bit cooler than the others. An infrared thermometer on that part of the header showed temps 60 degrees cooler on an idling engine. Seems like the exhaust leak may be unrelated to the other noise I have, but the sound is also apparent when you stick your head under the car by the drivers door.

[Tim555]

Video from under the car

https://youtube.com/shorts/sTq_7Pym0...vOYoK-Qcm1TaNr

[Matt B]

I tend to agree that it's not a coil pack issue. I had a faulty coil last year, one cylinder was down to no spark, and there was no noticeable noise but a MASSIVE loss on power. Car was merely driveable at all.
Which is interesting by the way, as in my early ZR-1 days I accidentally drove a short stretch with one spark plug wire plugged off - and didn't even realize it for a while.

So, for whatever reason a bad coil has a much more severe impact.

[Tim555]

Update on this. The noise seemed the go away. I was concerned about the sludge at the bottom of the dipstick so I changed the oil. It was pretty dirty despite the dealer saying it was changed in February (1000 miles ago, or so). I am very concerned about metal that appears to be in the oil. See photo. It looks gold. The rattling/lifter noise a few weeks ago sounded like lifters on a dry start, and then just a lifter tick.maybe a momentary disruption kn oilmto a lifter. Would this produce metal? I should mention I did have to drive a screw driver through the filter to get it off, but I don?t think this is from the filter.

[WARP TEN]

Did you save any of the oil? If so, you could send it out for analysis to one of the companies which do this. I don't know specifically who does it but others here have that information. --Bob

[Tim555]

Originally Posted by WARP TEN

Did you save any of the oil? If so, you could send it out for analysis to one of the companies which do this. I don't know specifically who does it but others here have that information. --Bob

I did save some. I?ll send a sample out when the blackstone oil sampling kits come in. I looked in the oil drain pan this morning and there was lots of glitter.