A little more info. I did the paper on the tailpipe test to see if maybe a valve was sticking but it does not appear to be. I also drove it until the noise started, shut it off and pulled the relay for the ignition and turned it over. You can hear the click while it's turning over and it seems to have even compression. A guy from TWS is supposed to call me today to see if he can help. The only thing I haven't touched other than spraying them down with parts cleaner is the rocker shaft assembly. I'm wondering if one of the rocker arms is seizing on the shaft after it gets up to temp.

 

Spoke to TWS this morning and they didn't know what to do either. Said I've done everything they would have suggested.

 

I counted 28 ticks in your 5 second video (seven sets of four). That's about 336 ticks per minute. That's about half of idle RPM (assuming 650 or so). That indicates valve train problem (cam, lifter, pushrod, rocker arm/shaft, valve parts), probably only on one cylinder.

I looked for my valve train tick by disconnecting spark plugs one at a time, but no change. Suspected defective rocker arm since I had replaced the arms and shafts (not too expensive) and read threads about loose pushrod caps. Narrowed it down to right bank by listening underneath with hose to ear (tick sounded only on right cat). Ran engine with valve cover removed and used mechanics stethoscope to pinpoint Cyl 6. Found intake rocker arm pushrod cap was loose. My point is not to say this is your problem, the point is that it is really difficult to narrow down the precise problem child, but it can be done. By the way the loose cap on the rocker arm looks like it is caused by a manufacturing defect, where the crimp in the aluminum arm is not made deep enough. Steel, one-piece rocker arms are available that don't have this potential problem, but I opted for an aluminum replacement. Hot, thinner oil made my tick louder. Hope this helps.

 

Out of desperation I threw some Rotella 15W40 in it. Once the water temp got to about 200 degrees the tapping came back. Reving the engine would bring the water temp back down to 195 but the tapping will not go away unless you cut the engine off and let it sit for 5 or 10 minutes.

 

Have you considered running a 170 or 180 thermostat and never let it get to 200? You can pop valcovers iff and have a look at valve train for looseness.

 

I don’t think water temp is root cause. I’m guessing if anything it’s oil temp. I’ve had the top end opened up several times. Nothing loose, lifters rotating like they should. No wear on cam or lifters. When I put new lifters in there were no signs of abnormal wear.

 

Bolts loose on torque converter or cracked TC?

 

Seems like you have ruled everything out except a slipping liner, how did you rule that out?

 

I suppose it's not impossible but they are top hat liners so the machine shop would have had to REALLY screw up when they put them in.

 

Sorry, guess I missed that. In that case I am betting on something in the torque converter/flex plate area.