My 99 si makes an awful noise when i put in the clutch, like a kind of grinding, it sounds to plates rubbing together. (That's the best description i can think of) Any ideas?

 

sounds like your throw out bearing is bad

 

When I had tranny issues (Civic w/B18C1 and hydro trans) and it was more of a rattling like a loud skate board bearing, if that makes sense, when the clutch was all the way out.

I thought I would be smart and buy a TOB (throw out bearing) in a clutch kit which would take care of any clutch problems. Long story short it was actually my internal input bearing (there is an external one as well) that was bad. So I ended up getting bent over by the shop. Have a transmission shop assess it fully and pay only for the fix you are looking for. Bright side, I have new synchros, seals, bearings, and half shafts. H aha.