f1ctionZ28

Hey guys,
Long story short, my ls1 spun a few bearings last year so I had it built by Victor of revenge power here in south FL. I'm currently in the process of putting everything back together, and right now I'm trying to torque down the rocker arms. I'm using a compression checker in order to find TDC on cylinder 1 and as I crank the motor a little nothing happens. The needle does not move in the slightest. When I do a full turn, all i hear is the sound of air escaping from somewhere. Mind you the motor is not completely pieced together, all it has on is just the heads (springs and valves are mounted on, rocker arms were tightened by hand), and its bolted onto the transmission, with the oil pan not torqued all the way, and the front timing chain cover off.
I'm getting really worried here, can anybody tell me if i'm doing something wrong?

ZeeOSix

Do you see the valves move when you turn the engine over?

mechanix565

turning the motor over by hand when its apart its totally normal to hear air bieng forced out of the exhaust side or spark plug holes it will give you a hissing sound.that is the compressed air in the cylinders coming out the exhaust valves this means you do in fact have compression maybe not enough to show up on a gauge but then again ive never used a compression gauge unless cranking the motor with a starter. if you are looking for tdc you can stuff a paper towl in the spark plug area make sure its in there decent so no air escapes but dont put it in the cylinder and crank the motor by hand pretty quick until the paper towl pops out then u no no1 is up top.i use a thread stopper but the cheap way out is a long pick or screwdriver just be gentle and dont crank it like a madman. one more question. why are you looking for tdc? changing the cam? otherwise theres really no need as there is no distributer.

Socket

iTrader: (6)

How do you use a compression tester to find tdc?

I agree with mechanix, you will hear air escaping when turning by hand.