Hard to answer well without knowing what you know.

There is a clutch plate installed between the pressure plate + flywheel, right?

Did you check the actual fit of the input shaft into the pilot bearing at the back of the crankshaft? (the bellhousing depth is proper for the length of the input shaft, right?)


The height of the pivot stud that the clutch fork rides on is critical, and must be checked + adjusted (carefully) during final assembly.

I like to be able to prove the clutch is engaging + disengaging by exercising the clutch fork before I drop it in the car - usually I use a crescent wrench for this, but I have seen people use a piece of all thread between the bellhousing + fork (where the clutch cable would run / where the slave cylinder actuates).