smoke from engine

Hello all,

This afternoon I made a flight with my Safari 30 minutes and after
refuelling I started again the engine and there was a lot of smoke coming
from the exaust. very impressif. A guy from the local air club told me this
could come from one valve not correctly positionned whenn the engine was
stopped.We discover later that there was plenty of oil in the exaust svifel
.. Some oil was even leaking on the heating duct. Finaly the smoke disapear
after 2 or 3 minutes running.
Any body has an idea of what exactly happened? The engine is from a crashed
r22 and has 700 hours since new. All gages oil pressure temperature cilender
head are ok .All comments welcome

Claude