Volcasurus is in my extra. I special summon cyber dragon (lv 5) and normal summon cyber dragon drei (lv 4). Drei activates and levels up to 5. I can special summon Cyber Dragon Nova and other rank 5 monsters except Volcasaurus. The only time I can special summon Volcasaurus is when I have two printed lv5 monsters (two Cyber Dragons).

-Noswal

As written in Drei's effect:

When this card is Normal Summoned: You can make all "Cyber Dragons" you currently control become Level 5. You cannot Special Summon any monsters during the turn you activate this effect, except Machine-Type monsters. If this card is banished: You can target 1 "Cyber Dragon" you control; it cannot be destroyed by battle or by card effects this turn. This card's name becomes "Cyber Dragon" while it is on the field or in the Graveyard.

You were able to summon Nova / Zenmaioh / Machu Mach because they were Machine-type monsters.

Here is Cyber Dragon Drei's text:

When this card is Normal Summoned: You can make all "Cyber Dragons" you currently control become Level 5. You cannot Special Summon any monsters during the turn you activate this effect, except Machine-Type monsters. If this card is banished: You can target 1 "Cyber Dragon" you control; it cannot be destroyed by battle or by card effects this turn. This card's name becomes "Cyber Dragon" while it is on the field or in the Graveyard.

Volcasuaurus is not a machine type monster so you can't special summon him during the turn you use Drei's effect to make all cyber dragons you control lvl 5