my1994z28

As stated above,I would not run a motor without the pushrod..I would be concerned that there is no oil coming out of the rockers while the valve cover is off..Maybe I missed it but,what is your oil pressure at?In the first video the sound did change when you moved to the front of the car,to me it sounds like a rod knock,if I had to guess I would say #6 rod is spun.I have a motor here that I just tore down and it spun #6 rod..For your sake I hope its a bad lifter.

bw_hunter

There is little reason to be concerned about the oil flow to those rockers as they wouldn't operate with the pushrods removed....

ctowns77

Oil pressure is still good. Which leads me away from it being a rod. Wouldn't it show low oil pressure if its rod? Anyone else?

charliediss

I am not sure that oil pressure would be compromised absolutely if the bearing spun...but I could be wrong. I do know that my oil pressure dropped to virtually zero when I spun the main bearing in my 97. However for what it's worth, this is what pointed me in the direction of a cam bearing. When you spin a bearing it begins to deteriorate at a very rapid rate. Not only is the bearing reduced to nothing, but the rod journal on your crank begins to degrade due to the increased friction/heat associated with the bearing free-wheeling around it. That said, all this extra material ends up mixed up in your oil and dispersed throughout the crankcase. It might be a good idea to drain your oil into a clean pan, run a magnet around in and see what you see...any shavings, any pieces? Anything look off?

Again, I would like to emphasize that I am a shadetree mechanic, not ASE certified, etc. I offer this advice as the direction I would follow and that which I have learned from practical experiences.

Charlie

ctowns77

New pushrods on #6 no change in noise from day 1 will investigate oil for shavings. Hoping no shavings means lifter collapsed. Again oil pressure steady at just above halfway.

ACE1252

Looks like to me the knock(first video) is timed with the movement of the rockers. I'm betting bad lifter(s) or no oil getting to one(or more) of them for some reason.

Here is rod knock...
http://www.youtube.com/watch?v=WA4G_LDEflo
http://www.youtube.com/watch?v=MQwem...eature=related

Edit:

After listening again...I'm not so sure now. Best thing to do is pull the intake and swap out the lifters. If that does not work, then pull the oil pan and check the rods. Or...grab a mechanics stethoscope. Start probing the engine with it. You'll find the source.

ctowns77

With stethoscope loudest between cylinder #4 & #6 but would lean on #6 side but sounds almost dead center between the two.

ctowns77

Should I drain oil and drop the pan first to check bearings or dig into the intake first??

charliediss

Path of least resistance, start with the easiest thing first...drop the oil.

$0.02