Today I was in the process of installing my heads when I ran into an issue. After torqueing the head bolts down, I installed two push roads and two rocker arms (torqued to GM spec) and tried to turn the crank to check for valve clearance. Just like LS1howto.com says you should. As I turned it made a small bang and the crank stopped moving (I wasn't turning it fast or hard). I tore everything down to make sure the dot-to-dot line up was correct on the cam gear and crank gear, it is dead on. If I spin the cam (with just the cam gear, no chain) it makes a rubbing sound and sounds like a lifter in cylinder 1. I didn't have time to pull the heads off today because I am working tonight.

Engine details:
LS1 with Brian Tooley Stage IV cam.
LS7 lifters, brand new (stock trays)
799 heads with BTR .660 lift springs
Stock valves
Stock pistons, rods, crank

Thoughts or theories as to what went wrong?

 

Sounds like your piston made contact with the valve. Take the head off and look for any signs of scuffing or marking on the piston and or valve. Make sure the valve wasn't damaged also.
Also pull the cam and check for any damage to the lobe in question.

The 799's are 64cc if I recall stock. Were they milled?

 

They Were Milled, But Only .003. It Does This Even Without The Push Rods And Rockers Installed. I Was Thinking Lifter Problem.

 

When you installed the two rockers, did you first install the rocker pedestal rail underneath them...?

If you remove lower bolt on the cam retainer plate (and put the sprocket back on), does spinning the cam still make the rubbing noise...?

Is there sufficient clearance between cam sprocket and cam retainer plate...?

 

Yes, The Rocker Rail Was Installed.

I Will Try Removing A Retainer Bolt Tomorrow.

I spent Time On The Phone With Brian Trying Pick His Brain. I'm GoingTo Test HisTheories Today When I Get Home From Work.

 

In for info

 

I pulled the driver side head this morning. The problem still exists. I'm pulling the passenger side as well later today.

 

Ok, so I pulled EVERYTHING off the engine. Cam spins perfectly fine with no grinding, no hesitation. Heads are completely off, lifters are out, cam gear is off. I still can't rotate this thing with it making a banging sound and stopping. I am completely lost!

I didn't drop anything in there, at least not to my knowledge. All bolts are accounted for. I'm completely lost and afraid something really bad happened.

Please help!

 

Is the oil pan off? Is this engine on a stand or in the car?
If on stand flip it over and watch the counterweights and rods move....see what happens at the point it locks up.
Something is hitting somewhere.

If engine is in car then bad news, you might have to pull it out.
Is this a stroker motor or just a stock crank, stock block?

 

How does it sound if you rotate it counter clockwise? Same or different?

 

Motor is stock LS1 bottom end. Yes, the oil pan is still on.

It does the same thing going counter clockwise. It'll turn a certain amount then it sounds like a hammer hitting and stops.

 

Sounds like your only option is to pull the oil pan, and see if you see anything out of sorts.

 

You might have dropped something somewhere and it's stuck in a place, blocking your crank from spinning.

Let us know what it was when you find the problem.

 

^That's what it sounds like to me too. Before you drop the pan maybe try looking down the lifter bores too see if there is a socket or something that might have fallen in.

Also, I see in your sig it's an M6. Is it in neutral? And I'm not trying to be a smart-a$$, it can be easy to overlook something simple when you think something is screwed up good and proper.

 

haha Yes, it is in neutral.

I just can imagine how anything would've fallen in there.

Does the k member have to come off in order to get the pan out?

 

I tried sliding a magnet around in the oil pan, no dice. I checked the lifter bores but no dice there either. Can I get a better view by removing the valley cover?

Is there anything other than the "something fell in there" that could be causing this. Cuz I really don't remember having anything near the engine that could've fallen down in there.

 

Removing the Valley Cover will only show the the knock sensor ports. You might be able to flash a light down the oil drain back holes and see if anything catches your eye by that's probably a long shot. Most likely engine is going to come out.

 

Only other thing I can think of is maybe taking a video of it where we can hear how it sounds and see how much the crank turns before locking up. Maybe that could give someone a hint...

Also, were the head bolt holes clean and 100% free of water/coolant? If they're not and you hydro-lock the bolt you'll blow out a coin-sized piece of the block. And if its one of the top bolts it will fall right on top of the rotating assembly.

 

Link to video...

 

I spent hours cleaning out the bolt holes. Used compressed air, paper towels rolled up, and ground down one side of an old head bolt. Did it for hours, literally, before all of them came up clean. I checked to see if what you said happened (about blowing a chunk of the block out) by sticking a socket extension in there and they all stop at the same point.

Also, nothing could be noticed in the oil pan through the drain plug hole. Stuck an extension magnet in and it didn't grab anything.