Help! Car wont crank after new lifter intalled.

[MustangFL]

hopefully you guys can help me out...
96 mustang gt, 5 speed,
i had to replace one of my lifters, after i installed it, i went to crank the car, with out the plugs connected, and valve cover out, just to see if it would stay in place. It crank, 1 turn and made a knocking sound and stopped. then i tried to crank it by hand, it will turn easily to both sides, but wont make a full 360. it feels like it hits a wall. like something is blocking it. And i dont see why the engine would be out of timing. i only loosen up the bolts that goes on top of the cam a little to have enough room to replace 1 lifter.
Thanks

 

[trinity_gt]

Sounds like PTV (piston to valve) interference.

Is the new lash adjuster bled down? Is the somehow being held open? How does it compare visually with the other valves on that head?

If a piston hit a valve when the engine was being cranked by the starter it's possible that the valve is damaged. Once you find the cause for the mechanical interference, do a compression test and, if possible, a leakdown test to judge whether the cylinder is okay or not.

 

[MustangFL]

It doenst look like its been bled down, comparing with the other ones, the new one sits higher.

 

[trombonedemon]

Didn't know our cars were interference engines, hmm explains the high compression and low emmissions.