oange ss

iTrader: (50)

noticed today pulling the tranny and clutch to change the rear main seal, that my crank moves about 1/16" forward and back (maybe a little less but it's close to that measurement), i never noticed this much play on any other LSX vehicle I've worked on, anybody have any ideas ? ..thanx

oange ss

iTrader: (50)

surely someone has some input...

techx

i hear you want a min/max of somewhere around .006"

oange ss

iTrader: (50)

i believe that is for a new build, there has to be a wear limit somewhere...or for someone to ease my mind a little....thanx

techx

its only going to get worse. i dont know an exact measurement but the bearing isnt too thick... (guessing) an eighth inch or so? i could get an exact measurement tomorrow, but either way, its not good. dont get me wrong i wouldnt panic or anything but definitely, schedule it.

but what do i know......?


EDIT: no, i believe i would panic... ive seen thrust bearings wear out. not an LS thrust but ive seen what it can do to a crankshaft.

nofearracing28

iTrader: (7)

thrust wall runout is .001 in.
crankshaft endplay is .0015 to .0078 in.

oange ss

iTrader: (50)

well that sux..thanx for the help

oange ss

iTrader: (50)

put an indicator on for S&G's, got .035-.037...so i guess i'm screwed...

nofearracing28

iTrader: (7)

ya...as long as your reading it right

Ferocity02

iTrader: (60)

Do a search for a history of this problem before you jump to conclusions. A service manual may be able give thrust measurement on a non new motor. On my 427 build, I ended up with a max thrust of .0035".

oange ss

iTrader: (50)

i have considerably more play than you did...

nofearracing28

iTrader: (7)

that came right from gm specs

HEMIETR

iTrader: (2)

I had the same problem on a SBC. The Oil pump P/U tube fell off during a race. Pressure dropped and I shut it down immidiately. I replaced the P/U tube but a few months later I started hearing a knock that I couldn't find. Come to find out the counter weights on the crank were making contact with the block. Goodby crank.

oange ss

iTrader: (50)

that aint helpin me any.....

techx

my phone doesnt take real good pictures but this ACL bearing is right at .090

oange ss

iTrader: (50)

so if the thrust surface is .090, acceptable limits from GM of .0015-.0078, assuming middle of the road at .0063, i'm about .028-.030 into the bearing....nice...what are the chances of milkin this for a year or so ?

oange ss

iTrader: (50)

i meant piece of mind HEMIETR, not info, i appreciate your input....

nofearracing28

iTrader: (7)

did you check your endplay?

techx

id say very good... in bizarro world. who knows, you might get lucky... i wouldnt let it go any further. how many miles on it?

oange ss

iTrader: (50)

.035-.037, posted above