LY6 Thrust wear, is crank shot?
02-08-2018, 09:41 PM
#1
LY6 Thrust wear, is crank shot? So I pulled my engine and transmission to swap my clutch out and fix the oil pan.
Had a spec twin disc clutch that was horrible to drive on the street. Also and now I know apparently put a LOT of pressure on the thrust bearing.
Well when i went to go and pull on the flywheel the crankshaft moved.... quite a bit. so I pulled the #3 cap and there is about 0.020"missing from the backside of the thrust bearings face (measured at 0.089" on the front and 0.068" on the back side.)
There is a decent groove in the thrust surface on the crank.
I forgot to measure the actual thrust clearance before I pulled the cap so I will check that tomorrow night to get an actual number but I am guessing it is over 0.030"
Is there a measurement I can take on the crankshaft to see if it is junk?
Do I put a new bearing in and take a measurement and if its too high then I know the crankshaft is junk?
Thanks for the help!
Shane
Had a spec twin disc clutch that was horrible to drive on the street. Also and now I know apparently put a LOT of pressure on the thrust bearing.
Well when i went to go and pull on the flywheel the crankshaft moved.... quite a bit. so I pulled the #3 cap and there is about 0.020"missing from the backside of the thrust bearings face (measured at 0.089" on the front and 0.068" on the back side.)
There is a decent groove in the thrust surface on the crank.
I forgot to measure the actual thrust clearance before I pulled the cap so I will check that tomorrow night to get an actual number but I am guessing it is over 0.030"
Is there a measurement I can take on the crankshaft to see if it is junk?
Do I put a new bearing in and take a measurement and if its too high then I know the crankshaft is junk?
Thanks for the help!
Shane
02-09-2018, 10:13 AM
#2
ModSquad
iTrader: (6)
Do you know where your thrust was set to initially? I don’t see any indication from your photos that your crankshaft is hurt at all. I’ve seen this happen in a circle track application, with an adjustable slave setup wrong. It turned the crankshaft blue from heat.
Put the cap back on, set the bearing before you torque it, and measure the clearance. I see a lot of folks set in their thrust too tight on LS engines.
Cut the oil filter apart with the right tool, and check for bearing debris.
Report back with what you find...
Put the cap back on, set the bearing before you torque it, and measure the clearance. I see a lot of folks set in their thrust too tight on LS engines.
Cut the oil filter apart with the right tool, and check for bearing debris.
Report back with what you find...
02-09-2018, 10:45 AM
#3
Do you know where your thrust was set to initially? I don’t see any indication from your photos that your crankshaft is hurt at all. I’ve seen this happen in a circle track application, with an adjustable slave setup wrong. It turned the crankshaft blue from heat.
Put the cap back on, set the bearing before you torque it, and measure the clearance. I see a lot of folks set in their thrust too tight on LS engines.
Cut the oil filter apart with the right tool, and check for bearing debris.
Report back with what you find...
Put the cap back on, set the bearing before you torque it, and measure the clearance. I see a lot of folks set in their thrust too tight on LS engines.
Cut the oil filter apart with the right tool, and check for bearing debris.
Report back with what you find...
If you compare the 2 photos one is completely flat and the other one has a groove in it.
The oil filter WILL have metal in it.
The reason I know is that the last 3 oil changes I have had cut the filter apart since it was a new engine (<1500 miles) and I was running it through break in. Each time it had metal in the filter.
Actually I posted about it over on hotrodders.com
http://www.hotrodders.com/forum/meta...ld-443369.html
I will measure the thrust tonight and see where its at.
Good thing is though so far it seems the oil filter stopped most of the larger particles. Nothing has seemed to collect in the heads or in the valley area.
I will most likely be taking the engine apart though and having the block cleaned thoroughly.
02-09-2018, 07:29 PM
#5
ModSquad
iTrader: (6)
I usually see .003-.004 on a new bearing setup. I like to open it up to .0045-.005 for a manual trans, and .008-.010 for an auto. I know guys that go .015 for race automatic setups.
Again, I don’t feel like your crank has gotten hot enough to be “trashed”, but it’s hard to tell from internet pics. Keep us posted.
02-09-2018, 09:01 PM
#6
.029 is about .024 too big, as I’m sure your aware.
I usually see .003-.004 on a new bearing setup. I like to open it up to .0045-.005 for a manual trans, and .008-.010 for an auto. I know guys that go .015 for race automatic setups.
Again, I don’t feel like your crank has gotten hot enough to be “trashed”, but it’s hard to tell from internet pics. Keep us posted.
I usually see .003-.004 on a new bearing setup. I like to open it up to .0045-.005 for a manual trans, and .008-.010 for an auto. I know guys that go .015 for race automatic setups.
Again, I don’t feel like your crank has gotten hot enough to be “trashed”, but it’s hard to tell from internet pics. Keep us posted.
