Among the list of things that could lead to too much oil usage is apex seal failure which causes greater clearance among the rotor and housing. This enables interior oil leakage into the combustion chamber resulting in grey smoke with the exhaust. After having burned by two ‘small-mileage’ 13Bs from https://https-jdmengineforsale-co20975.blog-ezine.com/38206302/new-step-by-step-map-for-jdm-mazda-rx-7-fd-13b-rew-engine-for-sale