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With the doghouse off, I can feel it very much in the block/bell housing and seems a little louder on the odd side.
Its a GM Performance connect-and-cruise kit 6.2L LS3/4L65E, bought about 2018 while the Van was being built and currently has 800 MILES on it. 800. I was driving normally, it started to knock intermittently going like 25mph, and by the time I could get a block to a Carls Jr parking lot it sounded like this.
I can't imagine what you could screw up on install to hurt an LS that bad. It has been babied like you'd baby a nineteen thousand dollar, completely GM stock, brand new powertrain. You could say I'm a little more than angry
GM Performance says suck it, its over 12 months old, so we aren't doing anything. So, assuming rod knock, what the heck could have caused it? and what the heck do I need to fix it? Rod bearings? Rod and crank bearings, Rod bearings and rods?
The Deets:
It had been sitting for about an hour at a buddies house, on a warm day, and this started 2 blocks after leaving. So, not over heated.
It still has 40psi oil pressure at cold idle, sender is at the lower port by the filter.
Compression is 125psi on #1 and #7 and the rest at 150psi.
Removing the coil plugs at idle one at a time = no change.
Oil was drained through a cloth and put back in, not a single piece of glitter but a tiny/tiny bit of grey sludgy stuff in the pan? I haven't pulled the oil filter and I did initially shut it off really quickly.
Plugs look OK
Valve covers off and all the rockers move while cranking. I didn't spin the pushrods.
So all I can do is pull this damn thing out and yank off the pan?
I have a 6.0l iron block engine for another project. Easy to swap physically but what about the GM ECM I'm using now?
Ok…oil filter will tell you condition of bearings. Cut it open with the correct tool, or tin snips. The fact that you you still have oil pressure says volumes. I wouldn’t touch a thing until I went through oil filter. If it’s clean, pull the bellhousing bottom cover and check your torque converter bolts, and flywheel condition. If it’s got metal in it, well you know what’s next. The oil pressure gauge gives me hope. Keep us posted please.
Damn, forgot to mention that. Pulled off the little plastic cover and rotated the engine. All three of the TC bolts are super tight and I couldn't see any cracks in the flex plate through that admittedly tiny inspection hole.
But thank you guys for the replies so far. I know what I'm in for, I would just like to be as prepared as possible before I dive in. I'm pretty scared of killing the interior:
DUDE!!!! I WOULD LOVE TO HAVE THAT VAN!!!!!!!!!!!!!!!!!!
Have you taken the AC belt off and serpentine belt off to verify its not something up there?
Thats a really high pitched sounding to be rod knock but anything is possibly I guess.
Defiantly pull filter
Also I would try removing torque converter bolts and sliding converter back from flex plate as far as it will go and crank it to see if its something in the torque converter or transmission.
it just doesnt have the "Normal" rod knock sounds that im used to.
Ever had a hard time cranking it? Ive had one hydro lock with fuel and tweak a couple rods just enough to bend them ever so slightly and it sounded similar to that.
I don't know if it's still in there and just smashed into the piston/head causing the knock.
I don't know if it made it's way out the exhaust.
I don't know if it was big enough to bend the rod, kill the bearing and thats what i'm hearing.
I don't know what "it" is. Foreign object from before or because of the custom cold air intake ('74 Van)? Chipped valve seat?
At least I know what I'm in for. Ugh. I'm going on vacation.
I don't know if it's still in there and just smashed into the piston/head causing the knock.
I don't know if it made it's way out the exhaust.
I don't know if it was big enough to bend the rod, kill the bearing and thats what i'm hearing.
I don't know what "it" is. Foreign object from before or because of the custom cold air intake ('74 Van)? Chipped valve seat?
At least I know what I'm in for. Ugh. I'm going on vacation.
Well…the good news is you know what’s going on and how to plan for it now. 99% of the time, you won’t know what happened, until it’s on a stand and the heads are off. I can’t imagine what got in the cylinder unless maybe a ringland broke, and a chip off the top of the piston broke off and did this. Your thought about the rod being bent might be on point here, and that’s what the knock is. I just got a 5.3 in my shop that was knocking. Tore it down and it has a bent rod. Bearing looks great, it’s just the skirt kissing the counterweight.
All other cylinders look ok in your engine?
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Not the same ol' knock 
. So, assuming rod knock, what the heck could have caused it? and what the heck do I need to fix it? Rod bearings? Rod and crank bearings, Rod bearings and rods? 
