Mold filling machine for molding a plastic container from a preform in a hollow mold and for filling the plastic container with product in the hollow mold, and with a valve head comprising a filling member for filling a product into the plastic container in the hollow mold, characterized in that a reaction chamber is provided for an ignitable gas mixture in order to inject a molding fluid, in particular the product, via the valve head into the plastic container by igniting the gas mixture.