[wbrockstar]

Did you get your crank turned,polished and use oversize bearings or did you buy a crank kit which comes with the crank & bearings??
If its the first,the machine shop either leaves it in place to turn the crank or removes it to turn the crank then reinstalls it afterwards.Thats always how Ive got my cranks back from the machine shop anyways.
If its the latter,I dont think they pre-install a pilot bearing,unless you tell them in advance to please do so.
I dont think Id drive without one though.It'll definitely wear the input shaft bearing and like stated below,it keeps the clutch disk centered on the flywheel.

I dont have experience with the consequences of running an engine without a pilot bearing,but I found a thread with what can happen.This is not a Mustang forum,but a pilot bearing does the same thing regardless of make or model.



" The pilot bearing is pressed into the crankshaft. It’s function is to support the forward end of the transmission input shaft, keep the clutch disc centered on the flywheel, and allow the input shaft and flywheel to rotate independently of each other when the clutch is disengaged. When a pilot bushing/bearing gets worn oversize or disintegrates, you may experience erratic clutch performance and/or shifting problems because the front of the transmission input shaft is essentially free floating. With a failed pilot, your transmission input shaft is no longer held in rigid alignment with the mainshaft and counter shaft.The gear on the input shaft transmits full engine power to the countershaft in all gears so any misalignment will cause that power to be transferred from gear to gear with inadequate tooth contact. Given time, metal fatigue will weaken the gears until a catastrophic failure occurs.Noise may also come from a worn or dry pilot bearing. Such a bearing tends to “whine” when it is out of grease. This noise usually occurs when the vehicle is stationary, with the engine running, the transmission in gear, and the clutch disengaged. Just my thoughts "

" I have to disagree with you comments about catastrohic failures. I have dealt with rigs which had missing pilots bearings on three different occasions over the years. The misalignent allowed by a missing pilot bearing will case increased wear on the input bearing, and a misaligned clutch (usually causing noises and some increased wear, but no noticable performance oddities in my experience.). But the misalignment is not sufficient to cause any sort of gear failure. Increased wear of the input and it's mate on the counter shaft, to a small degree, yep. But in the real world opposed to the lab, you wil not see wear to the point that causes any sort of internal gear failure in the tranny. If you did operate the rig in this condition for long terms use, the failure would be the input bearing. Now THAT occurance could certainly cause major internal damage. But the misalingment of the input due to a missing pilot wil not cause fatigue induced failure of the gears.

Not to say that you would want to purposely neglect to install a pilot bearing "