Hello, this isn't actually LT1, but close. . . my dad has a 96 k1500 with the 5.7l/350 vortec v8. It developed a bad knock two weeks ago, so he stopped driving it and last weekend pulled off the oil pan and checked the rod bearings, which all appear tight. He then ran it w/the pan off and the knock is definatly comming from higher than the crank, but it also sounds lower than the rocker arms.

In the oil pan, he found 4 approx. 1/2" needle bearings (like what you'd find in a u-joint on a drive shaft) and part of the casing for it (a small junk, looked like the overall dia. would prob. be 1/2"-1"). Anyone know what these could be from? He's trying fo find a parts breakdown for the engine now and is hoping to fix it over the weekend as he's w/out trans. right now.

Thanks for any help,
Justin

 

There are several brands of lifters that use needle bearings on the roller. The lifters that I have are that way. Maybe one came apart? Just a thought.

 

Thanks,

I suggested he pull the valve covers and check them, though he said the knock sounds like it is coming from lower down. Maybe the bearings came out of a rocker arm and then messed up something else. . I hope not. That's the only thing I could thing of though. . . .

-Justin

 

lifters, they are under the intake, that Vortec will use roller lifters

 

hmm. . . I didn't even think about that. . I bet that's what it is! -sounds like exactly where the knock is coming from too. . .

Thanks for the help guys,
-Justin