Heres some notes ive been taking lately. I just roughly write them down before i forget.
"
-Knocks at idle on cold start
-Different everyday, sometimes good, sometimes bad
-Quiet in summer, bad in winter
-Knock stops when, holding a gear and rolling
-Takes about 10mins to stop knocking while driving
-When first noticed the knock, most of the time it would greatly improve after about 30secs at idle. Now takes 10mins of driving to go away.(Might -be comparing summer to winter though)
-Have replaced lifters with LS7's and Smith Bros Rocker Trunnion Bearing Upgrade (Solid bronze bushes instead of needle roller bearings). Car came back quiet, but i had them done in summer.
-First noticed the noise all of a sudden, didnt used to make the noise
-Oil pressure normal on gauge (300KPA cold at idle, 200KPA hot, pressure rises from there with engine revs)
-Have disconnected one injector at a time - no change in knock sound
-Have pulled off rocker covers, all rocker arms have no up and down movement, only side to side. Have not checked lifter preload properly though.
-Knock seems to be too slow for bottom end, but too fast for valve train?
-Whatever the knock is, its definately ONE component, not multiple.
-Cant hear any difference in loudness from one side of the motor to the other
-Sounds like the sound resonates from the sump? Sounds like about the thickness and volume of aluminium
-Sound is consistent when gently revving when stationary i.e just off idle to 3000rpm (Sound volume doesnt change)
-Its not louder or quieter depending on engine load
-Worse in the morning startup, sometimes just as bad in the afternoon startup, but sometimes nearly silent on afternoon startup even when the weather is very cold (Not consistant)
-Before lifters were replaced (Just coming out of winter/Start of Spring)
-After lifters replaced just as the weather cooled down (2 months after lifters replaced)
Same noise in both videos"