Is there a simple guide for 's' vs 'sh' pronunciation in words?

Consider the following words as examples:

1) Version
2) Progression
3) Differentiation
4) Fission
5) Fusion
6) Insurance
7) Sure

I pronounce all these words with a 'sh' sound even though it is not explicit in written. I have heard people using some of these words with a 's' sound, especially #6. Both myself and the folks I have heard talking are non-native English speakers.

Are there any defined rules that tell when 's' or 'sh' sounds should be used?

Solution 1:

This comes with the usual warning about rules for English:

Rule .1. -ive makes s sound S. But -ion creates ZH unless after ss then SH.

massive s, (im-)passive s but (com-)passion sh, invasive s, but invasion zh,

adhesive s, but adhesion zh,

divisive s, but division zh, derisive s, but derision zh

(per-)missive s, dismissive s, derisive s, indecisive s & s, mission sh, indecision zh, derision zh,

explosive s, explosion zh, erosion zh

extrusion zh,

effusive s elusive s fusion zh, effusion zh, illusion zh, allusion zh

Rule .2. -tion makes SHn and the preceding vowel is (often) made long.

(indication sh)(station sh) (relation sh) (depletion sh) (contrition sh short -i-) (emotion sh)(motion sh) (devotion sh) (contribution sh),
But sometimes "s" (initiation, s?sh)

Rule .3. Visual is unusual.