Cam chain tensioner

Hello all,
I am doing up my 850 and a mates 750 engine. The 850 cam chain tensioner had the remains of some sort of rubber material, whislt the 750 has just plain steel. Any pro's & cons of the two types. I am not ready to spend big bucks on an auto system just yet. Is there any details for the budding home engineer to make thier own?

Regards Richard

You have a man named Cork who makes them in Australia for cheaper than the US auto model. They work with no mods to the case and were not big bucks. Reg forom Brisbane can hook you up. They are made from a Jap car part and push the chain from the inside instead of the outside. They work real well. norbsa