  For the collapsar scenario to be effective in the production of Gamma Ray
Bursts, the infalling star's angular momentum $J(r)$ must be larger than the
critical angular momentum needed to form an accretion disk around a blackhole
(BH), namely $J_{\rm crit} = 2r_{g}c$ for a Schwarzschild BH. By means of 3D
SPH simulations, here we study the collapse and accretion onto black holes of
spherical rotating envelopes, whose angular momentum distribution has
transitions between supercritical ($J>J_{\rm crit}$) and subcritical ($J<J_{\rm
crit}$) values. Contrary to results obtained in previous 2D hydrodynamical
simulations, we find that a substantial amount of subcritical material fed to
the accretion disk, lingers around long enough to contribute significantly to
the energy loss rate. Increasing the amount of angular momentum in the
subcritical material increases the time spent at the accretion disk, and only
when the bulk of this subcritical material is accreted before it is replenished
by a massive outermost supercritical shell, the inner engine experiences a
shutdown. Once the muffled accretion disk is provided again with enough
supercritical material, the shutdown will be over and a quiescent time in the
long GRB produced afterwards could be observed.
