So after several months, my mechanic has finally finished preparing my 02 z28. It arrived with the heads on, but lots needed to be done. He pre lubed it today and when he went to turn the crank manually , it only turns 180° in either direction before it locks up. what would cause this?

 

Possibly rod clearance issues.

 

Ask your mechanic how he (she) assembled the valve train with that limitation?

 

He says it turns smoothly right up until it stops.

 

did he check PTV clearance? Would almost bet thats your problem if its not stock.

 

The guy I bought it from said it's all stock.

 

You're guy number 2 that this is has happend to this week. Hes having rods hit his cam, or so they think.

 

I dont see how the rods could be hitting his cam..

 

Thats what I said, unless they have a stroker crank in there?

 

No, the cylinder wall would be in the way.

 

I was told it's all stock except for some (used) yellow ls6 springs.

 

The cam gear and the crank gear for timing, are COMPLETELY incorrectly installed. My car did this but it was because a 4 in crank doesnt clear a Canton oil pan with out a little love.

 

So how should I go about verifying and correcting this?

 

Same thing happening to me, 180 degrees each way, won't fully rotate. I'll let you know what happens with my setup once my builder gets back to me.

 

Make sure you dont have a pushrod sitting on the edge of the lifter, I had this happen and made me look like a dumbass for about an hour on my LT1.

The valve is opening very early because the pushrod is too long because its not sitting down in its cup in the lifter.

Look at the pushrod it will look slightly crooked, you can look straight down the pushrod with a flashlight.

 

no, it's not the pushrods, it still does this when we took all the rocker arms off. the crank rotates a little bit, and then it's like it hits a solid object. turn it the other way, and same thing.
my builder is going to pull the heads and see what happened.

 

A different engine builder who knows what he is doing?

 

Pulling the heads won't tell you anything, pull the pan.

 

LMAO. Sorry but that was funny. That's like saying falling isn't bad it's the sudden stop at the end.

Is the car an auto? I have seem people not tighten the torque converter bolts up and they hit inside the bellhousing.

 

Pistons on rods backwards?...don't ask me how I know this....