Conversion? Have you tried spacing the clutch slave cylinder away from the bell housing? I'm thinking you have no free play at the slave cylinder. Try undoing the bolts 3mm and then try again.
Good luck and lets us know how you get on. I've got to take the sump of mine soon. My 300tdi hybrid decided to develope a big end knock while I left it ticking over on Saturday. Not a happy chappy. :(