Bad lifters causing knock noise and nosing over at 5500?

[driven87]

Took my freinds car out the other night to help out with some stuff. Rolled into second gear and it felt like it nosed a little shifting at 6000 then in third it pulled again till about 5500-5700 and it nosed over big time and he let off the gas. After looking at the data log the A/F's were 10.8, boost was 27 and timing was 20. Showed a quick little knock as soon as it did that. Decided to let it cool down and check it out again this time roll into it from first gear and it was fine till third gear where at the same rpm it nosed over big time and picked up a litte bit of knock as soon as it did that. Took the car back to his house and checked over things and the tune was right on again till that rpm. Decided one last time to try just rolling into third and seeing what was up. Car pulled hard till that same rpm again and nosed over only this time i was missing just a little bit now when driving and also had a slight knocking noise. Took the car back to his house and the misfire was evident at idle and when revving in park the noise was a loud knocking but seemed like top end. oil pressure was good and clean. Now the weird part of the story when he installed the rockers this time around he let them soak on a plastic bottle with mineral spirits. The bottle melted when whe was no around and a bunch of crap was in the lifters. He cleaned them best he could and put them in the motor. He mentioned he had a rough time adjusting the valves all of a sudden some would feel like nothing was there when tightening but he kept going. Car is a 9 second ride and has about 1k miles on the new set with no problems till this. Back to that night we popped the valve covers off to check over stuff and some pushrods seem just a tad looser then they should be but nothing bad. We go to re adjust all the rockers and just about all the lifters are not pumping up or feel like there is no tension to go that 1/2 turn and the adjustments on all of them are all different. Could the lifters had been letting the valves float on those passes? Could the lifters just be shot enough to make a knocking noise? Could something have happend to make it misfire? I did not think if a bearing spun that the motor would misfire? These are comp cam hyraulic roller lifters that are about 4 years old in a 9 second motor. Gonna help him tear into it a little bit more next week but im just wondering if the lifters are causing all these noises and misfires? Thanks guy im hoping a lifter change will fix everything.

 

[Slow91z]

I'd be looking for a broke valve spring...Only way to know is to get it apart.

My stock 90K mile lifters were so worn out I could press the plungers with my finger, but all they did was clatter when it was started cold for a second and as soon as oil pressure hit they were fine...Ran as good upstairs as possible for a stock cam motor.

 

[turbo nasty]

Now the weird part of the story when he installed the rockers this time around he let them soak on a plastic bottle with mineral spirits. The bottle melted when whe was no around and a bunch of crap was in the lifters. He cleaned them best he could and put them in the motor. He mentioned he had a rough time adjusting the valves all of a sudden some would feel like nothing was there when tightening but he kept going.

The above action was not the best move.
9 sec motor and "Iffy" lifters lash/preload/etc and above engine assembly tactics dont jive IMO.

Time to go back in there. Check everything correctly