You shouldn't need to, as long as you got the right clutch, and the right flywheel, no "spacers" are needed.
Start at the gearbox, check the pivot fork to make sure it's on correctly and the end of the clutch cable is connected properly.
Check the cable sleeve connection at the firewall, has it got a rubber stopper, adjusted correctly with the horseshoe clip about half-2/3's of the way down the ribbing? I also had a problem once, where the stopper had torn a hole in the firewall, and when I put the clutch in, it just pulled the whole lot in, and didn't move the clutch at all, so check around the stop on the firewall for rips.. but I don't think thats' your problem.
Check the pedal connection under the dash, although it won't be this.
If you've run out of options, you're going to have to pull the box off, make sure the clutch plate is installed the correct way around, (I've seen lots of people make THAT mistake..

) and the pressure plate is in good condition with no cracks in or behind the tension plate. Make sure the thrust bearing spins ok, is clipped correctly into the pivot fork. Other than that, there isn't much else to go wrong in a cable clutch system.
I can't remember if 3A-U's had a spigot bearing or not, its' been ages since I did one.. can anyone help?
Daily driver: Toyota RunX/Toyota Caldina
Ex: 2x AE101, 5x KP60, KP61, EP71, 3x KE70, KE72, AE70, AE82, 2x TE71, AE90, AE92, ST170, plus 11 Hondas, 12 Nissans, 6 Fords, 4 Mazdas, 3 Mitsis, an Isuzu and a Lada!
