So, if you're searching for "clutch fork" damn!  This happened to me too.  I installed a new clutch for my restoration on my 6/71 240z.  Finally got to the long awaited stage of engine installation.   It went well, until I got underneath the car to torque the bolts and bumped the clutch fork and thought why is it so loose??  It was almost at the end of its throw before the throw out bearing contacted the clutch springs.  That's when I searched for "clutch fork"  Exactly the thread I was looking for.

So, I've installed many clutches in John Deere forestry equipment.   The manuals always give you the distance from the flywheel to the diaphragm springs.   These springs are adjustable. You bolt your pressure plate down, measure the distance,  and if adjustments need to be made, you unbolt it, and adjust, until you get it right.

After reading this thread, I realized I had to pull the engine out and see what's up.

I adapted my Deere gauge for this Datsun, measured the distance from the flywheel to the diaphragm spring.  I reinstalled my old clutch (1981) and measured that.  I installed my old pressure plate with the new disc and measured that.

The problem is in the service manual they use 'distance pieces' instead of a clutch disc.  I do not know how thick those are.

I should have measured how thick my new throwout bearing is and my old one, but I didn't. 

I ended up putting the 2 washers behind the pivot ball and am happy with the results, but still don't know why I had to.

Is it the combination of resurfacing the flywheel and the new throw out bearing where I lost the distance, I don't know. 

Welcome to the “why did I have to do this” club! We’re inducting new members every year it seems. 

There are like five different throw out bearing collars with different stack heights. Lots of variables. Best practice is to dry stack the pressure plate, bearing and collar on the bench and measure the new parts for stack height.

@Patcon Do you know where I can find a listing of the collar lengths?

@mayolives Thanks my friend! Now I need to find the Nissan P/N.

Here's an old post from TerrapinZ with good measurements. Just noticed that posts don't have numbers anymore. Bummer. It's about 1/3 down page 12 if the link doesn't take you directly there.

Thanks everyone. I’ve identified #4 as p/n 30501-K0401. Still available through Nissan. Should have it by Friday. Still available since it Fits later model cars and trucks. I’m running the T5 transmission from a 83 ZX 280et. I’ll report back once everything comes in. Thanks for the help. Much appreciated.

Any time! LOL