RockinWs6

That's not a rod bearing noise.....prolly broke a rocker....geez what is this just toss out anything when you don't know thread?

bigtodd

iTrader: (4)

I'm going to start at the top and maybe it's top end related. If not going deeper till I find it.

1FastBrick

iTrader: (16)

A knock that loud and that much smoke, I wouldn't be surprised if it was a broken piston. curious to see what you find once you get the heads off.

JOHNNY59

iTrader: (398)

doubt its a rocker, but since I don't know anything (quote from above) check this post out! listen to the video and then check out #15 reply.

https://ls1tech.com/forums/generatio...ine-noise.html

chevybayboy

iTrader: (6)

That's exactly how mine sounded when I spun a rod bearing had great oil pressure trouble staying running... I think it's a rod bearing

bigtodd

iTrader: (4)

Once I get some time from work I will start to dig into it. I'm going to say its a rod.

JOHNNY59

iTrader: (398)

any word yet?

RockinWs6

well it was rod noise in that thread..........this aint. Its cam related.

LilJayV10

iTrader: (39)

Before you try and start it again see if you can turn the engine over with a ratchet on the crank bolt. With it knocking that loud and it stopped running on its own I would guess it either dropped a valve or hydrolocked.

DMM

The last three noisey LS motors I have fixed was with LS4/LSA oil pumps (an LQ9, LQ4, and an LS6). They all had good oil pressure, 40 at idle and 40-60 driving. The two LQ motors had the exact same knock on start up and the LQ9 started having a knock at all times. The LQ9 was my cousins Denali, well taken care of. All were fixed with a new pump.

64post

iTrader: (5)

May not need to drop the pan,(yet) dump the oil into a real clean container and examine it. If it's a rod bearing there will be metal flakes and particles in the oil. You could try draining the oil though some type of filter to catch the carnage. That doesn't sound good. Once heard a cracked flex plate make a similar sound.

KevinR

What crystal ball are you using?

RockinWs6

Rod bearing wouldn't make it run like it is, something else is going on. Broken rocker valve pushrod lifter etc.

redbird555

iTrader: (14)

The cam is spinning at half the engine speed a rocker or valve would be rythmic and would not vary linearly with rpm. This does, sounds to me bottom end related a hole in the piston would def make it run like that and yes I have seen quite a few spun bearings that make the engine shake and stall like that. Its not very uncommon, a valvetarin problem would be roughly at half engine speed and wouldnt be that "heavy" in sound. Oem rockers very rarely if ever fail and break besides the needle bearings

WS6ICK2k

Hate it for you I believe that ones also in the bottom end. Keep us posted with what you find.

96lt4c4

iTrader: (5)

Guys saying its not in the bottom end, your stupid.

Thats a rod knocking.

bigtodd

iTrader: (4)

Finally had some time to dig into the motor. I didn't get much done but did get the intake off and found a cup or more of water in the manifold. What can cause that?

RockinWs6

Wow prolly a broken piston, rain water leaks past the windshield cowling and runs down on top of the intake manifold. The intake is loose and the water leaks past the seals and into the engine. As you start you slug a cylinder with water and it hydro locks breaking the piston-rod etc. Good Luck.

I knew it wasn't a bearing.....

bigtodd

iTrader: (4)

Damn sucks, the intake manifold bolts were pretty much finger tight. Owell time for a junk yard 4.8 and a turbo. Anyway to stop the rain from coming threw like that?

RockinWs6

Be sure to seal the windshield cowling so this never happens again. You may be able to fix this with a used rod and piston. Pull it apart and see how bad the damage is. If it didn't crack the block you can fix it.