I think I know what you mean, but I need to clarify a couple of things:
-The "valve" that connects to the lever arm is the Wastegate Actuator. It's the tin can shaped thing with a vacuum hose connected to it, right?
-You say "underneath the turbo"- on most Delicas the wastegate actuator is *above* the turbo, by the inlet manifold, connected to the lever by a long rod. (Pajeros have the wastegate actuator underneath the turbo, and maybe some Delicas made after 1995).
Anyway:
The wastegate actuator has a spring inside that pulls on the connecting rod, normally holding the lever arm up (closed). When the actuator opens the valve, the connecting rod is pushed out of the actuator.
On a regular, actuator-above-the-turbo Delica, the connecting rod should be 22cm long, measured from the lever arm pin to the actuator. If you make a new connecting rod that's the wrong length, you'll change the amount of boost you get before the wastegate operates.

- Actuator_zpsmklly4cx.png (106.82 KiB) Viewed 8123 times
HTH
Nothing says "poor workmanship" more than wrinkles in the duct tape.