Morals in Marx

Marx's work is divided between denying morals blamed for beeing powerless and difficult to conceive within materialism, in favour of a scientific and political approach of society, and asserting clairely moral values, like Kant's, in his criticism of capitalism and his communist project. This internal tension has to be analysed since there is not such thing as morals of Marx, but morals in Marx, which really says smothing and prevents for separating politics from morals