Started getting this noise yesterday after a pull. Rockers don’t have extra play and oil pressure is good. Engine was rebuilt last year with all new bearings, ls7 lifters and trunion upgrade. Running boost for the past week, 11-12 psi and I believe 11* timing. Afr is 11.2 at wot. Hoping it’s just a lifter. Pulling the head tomorrow. Engine is 99 lm7.

 

Speeds up with rpm. Definitely coming from #5 and maybe some from #7. It’s quiet with a stethoscope at the head and oil pan but loud at the cylinder wall.

 

 

That is very bad. I can't tell if that is top or bottom end.

All rocker bolts are tight? Nothing loosened up? I'd take them off and go through the install procedure again.

Drain the oil into a CLEAN pan and check for sparkles.

 

everything looked and felt good under the valve cover. head will be coming off tomorrow and I’ll report back.

 

It sounds top end to me. A rod knock always seems to have more deeper metal to metal sound.

 

Are they stock rockers? Do they have stock or bronze trunnion bearings?

If the head is coming off anyway, pull the lifters and check the rollers and cam for any damage.

 

stock rockers with BTR bearings and keepers. Still the needle bearing style. I will be pulling all the lifters on that side and I will inspect the cam.

 

Where did you get the "LS7" Lifters?

 

Sounds like it is up top.