has anyone ever been able to change a cam without loosening the tensioner ?

i changed mine back to the standard Eb this after noon and i didn't need to loosen the tension to get the cam gear off.

it runs perfect with no rattles or anything.

Yes, I did but you need to keep the chain under tension to stop the tensioner putting more tension on the chain. If you let it go slack and it went on easy then I would be wary you may have a stretch chain.

Not necessary. Those chains can have stretched mofo chains, aslong as cam is dialed in and ignition timing is spot on. seen them sheer off cam bolts, (get an AU one), but never jump a tooth.