Robertvon

Ok I've got a junkyard 5.3 I'm swapping into my S10 and was pulling it apart to clean it up after noticing some water in the cylinders thought I'd do a quick hone and put it back together....NOT.....last night while I was inspecting the bottom end I noticed two of the bob weights had what looks like surface rub. WTF so I moved the pully in and out and this thing has 1/4" play how in the can that happen?

So my question is .......Is this common... and is this crank now junk?

what was supposed to be just a drop in is turning into a freaking project.I did'nt want to dump $ into the block yet...I just wanted to get it running!

Any thoughts,insight,or suggestions would be appreciated

KCS

iTrader: (20)

That sucks, but I feel your pain. Same thing happened to a friend where a "low mile" LS1 turned out to have the main and rod bearings on the verge of failure. Even the rebuild was a PITA as I discovered the rods were all at least .001" too tight, the crank was turned .020", and there were 7 pistons and rods from an LS1 and 1 from an LS6.

Anyways, as for your dilemma, is the crank moving back and forth 1/4" in the block? If definitely should run like that if so. Start with pulling the main caps and bearings to inspect the #3 main bearing, specifically the thrust flange.

Robertvon

Yeah it moves that much back and fourth...you can see marks on two of the bob weights where its rubbed the block on caps #2 & #4.

KCS

iTrader: (20)

Can you see if there is a thrust bearing in the #3 main cap?

Robertvon

I'll look when I get home ...I seen the marks on the crank and said the hell with it and shut the lights off and went back into house...I was pissed. If this crank is no good now what I dont have a big budget that was the reason for dropping it in .....do i find another 5.3 or just get a 6.0 my original plan was to put the 5.3 in and drive it till I got a 6.0 to built

01ssreda4

iTrader: (96)

Acceptable should be in the range of .004-.008. Mine at .040 had the crank rubbing the block. It was still running at the time.

Robertvon

It appears that the thrust bearing wore a groove in the crankshaft there for causing the rub marks on the bob weight as it moved forward.

Does anyone know what could of caused this I got the motor and tranny together so I need to find the source before I put all back together and have it happen again

01ssreda4

iTrader: (96)

Converter or clutch, improper internal engine assembly, something wrong in the trans. Could be a bunch of things. It can be difficult to impossible to diagnose sometimes.

LS1MCSS

iTrader: (18)

I would say that crank is junk. Any chance that motor was sprayed? Maybe the convertor ballooned and pushed forward on the crank?

Robertvon

what sucks is I dont know any of the history of motor or the tranny

so hopefullyI can figure it out....if not I guess I should go through the tranny I was already gonna replace the converter. Looks like I have to find another crank too