Ok, at first I thought it was a rod which it sounds like the crank is fine there is no dents in the oil pan but there is this irregular knock it speeds up when rpms are higher the timing chain is ok I'm not sure about the actual timing itself I drove it on this for about 13 miles it drives nice except for the noise there is no smoke or nothing I'm really puzzled on this I'm about 99.9% sure a rod would have the engine smoking any help would be greatly appreciated thank you for your time


I have a video of it knocking posted here http://vids.myspace.com/index.cfm?fu...deoID=43711034

Heres another vid of lifters and oil pressure
http://vids.myspace.com/index.cfm?fu...deoID=43772236

Vid of in drive and steady RPMS
http://vids.myspace.com/index.cfm?fu...deoID=43781339

Threw it in reverse and drive and reved it till my tire started to spin and the knock quiets down but is still there

 

That "BBBRRRAAAAAPPP" when the engine first started - almost sounds like maybe a cracked flexplate? I assume you're running an automatic trans?

Just a side note - a spun rod bearing will not cause it to burn oil, nor would a spun main bearing cause dents in the oil pan.

 

That bbbrrraaap is the knock

 

loose rocker/valves need adjustment?

 

Pontiac motors, IIRC, do not have an adjustable valve train. Theres a torque spec for the rocker nuts.

 

I don't think it's a rod knock. I vote torque converter bolts, cracked flex plate, or flex plate to crank bolts loose.
In the first video you can hear the "sheet-metal" sound and in the second video, you can hear that the knock is not the regular "tock-tock-tock" of a rod, it is an irregular knock with a "rattle flavor".
Could you post a vid with the engine in drive, with the throttle a little above idle? Flex plate problems will get noticably quieter in this instance.
EDIT: oh I forgot, it also could be the crank counterweights hitting a dented oil pan...

 

Oil pan is perfectly fine

 

i had a truck that sounded similar to that, check your torque converter bolts, mine were loose (1 missing)

 

Hey, did you fix it????? Flexplate????? That's what it sounds like. Please let us know

 

Replaced the engine with another 400 and traded it for a GTA they guy I gave the engine to said that the oil got so hot that it burned into the cam push rods and all that plus some sludge build up didn't help it