cubals1

I rebuilt a 2004 6.0l gen III block & heads. All new bearings & rings. Heads were done (Not shaved as they were straight). Nothing insane, just a stock rebuild. Assembled the lower end and everything went back normal. Motor spins nice, no problems. Put heads on, spins. Torqued head bolts and the thing binds up. As each bolt is torqued it only gets worse until it only goes a 1/4 spin either way, not a full revolution. It makes no sense why as the bolts don't reach into crankcase and hit the crank. Same length (New) head bolts. I cleaned the threads & blown out the holes. I am stumped. Not my first rebuild but first LS rebuild

Darth_V8r

iTrader: (4)

Is that with or without the rockers bolted on? if they're on, I'd double check the cam degree. Only thing I can think of is PTV

Edit -- unless there's a deck height issue?

vettenuts

iTrader: (4)

Almost sounds like the piston is hitting the deck. What gasket was used? Might want to check the out of the hole height of the piston at TDC.

RockinWs6

Pull heads back off and check the piston height at TDC on all the cylinders. Also check the head gaskets are not shrouding the pistons.

cubals1

No rockers or pushrods or sparkplugs. Factory dished pistons, new rings. Felpro head gaskets, compared to the original steel shim head gaskets the Felpro gaskets are slightly thicker. I tried with the heads off the original motor and same thing happened. Once the first head bolt gets tightened is when the binding starts. By the 3rd head bolt the stoppage of rotation happens. New main & cam bearings in block.

Darth_V8r

iTrader: (4)

What is the head gasket bore?
Did you have the block decked? How much if so?

Does it do it on both banks or only one bank? Or is it one head or the other regardless of which bank it is used on? Or if you swap head gaskets, does the problem follow it?

KCS

iTrader: (20)

I'm betting this is the problem.

cubals1

Block and crank checked out good at machine shop. Crank was polished. When I took it apart main and rod bearings looked good, cam bearings looked like weld splatter, very weird. Had the shop install cam bearings, hone cylinders. I put back together, new cam, timing chain, rings, bearings. nothing fancy, normal rebuild. Doesn't matter what side. Same outcome. Stop rotation . I did not measure the head gaskets bore but laid the original steel shim gasket over the Felpro. Same size bore. The old motor 6.0 head and steel gasket with old headbolts has the same outcome. Stop rotation. Machine shop has never heard anything like this. I'm stumped

big hammer

Pistons are either hitting the gasket or the head

farmington

iTrader: (14)

Put a little clay on piston top and put heads on. Rotate. Remove heads. See where interference is

brandon6.0

iTrader: (32)

Pics would help this situation greatly!

BlwnLs1GTO

iTrader: (12)

Please do this first.
Then switch heads and repeat. Rule This out Now!
Check timing chain lineup while you're in there, too. How much are the pistons out of the hole?
You've got some great engine builders helping in here (Not me) and I'd take their suggestions seriously.

cubals1

Got it! Ordered a set of steel shim head gaskets and no problems whatsoever. All back together and running. Thank everyone for their help!