Noise in CAS Sensor,...not the CAS Sensor

[dr evil]

I rebuilt the motor in my Elan Turbo and after many skinned knuckles it fired right up. Everything appears normal except a noise that eminates from the CAS sensor. It sounds like a bad idler pulley sounds on a regular old V8 style motor. Figuring the CAS has something wrong inside I replaced it with a spare known good CAS sensor and the noise was exactly the same. So it's not the CAS sensor. I loosened the CAS and pulled it out a few thousands of an inch and noticed it made the sound worse. I pulled the Cam cover and inspected all the cam bearing caps (all were good). Looked at the tappet faces as best I could,...all look Ok from the cam in place inspection. The cam belt was replaced with a new one,..and that end of the motor is quiet.
My differential diagnosis includes the possibility that the noise is actually from the cam belt end and is being translated up the exhaust camsahft and is using the CAS as a sort of bell/amplifier for noise at the other end. Also that the cam belt or tensioner may be at fault. Less acceptable might be the cam has somehow scored the lower bearings on start up ( I doubt this as I did no maintenence to the Cam or components during this rebuild,...they were serviced 2000 miles before and were silent in the interim). I used a start up lube on all the cam/tappets and valves. The only change in the cam driveline was to change the belt.
Could belt tension be wrong and cause this? Loose bolt on the cam or components on the drive end?
I have a spare (used) cam belt idler,...might install that.
My plan is to support the Starboard side of the engine and pull off the cover and check all the bolts, possibly replace the idler and triple check the cam belt tension,...maybe even loosen it a tad.
Anybody ever experienced this before??? I browsed the posts and their was some discussion on cam belt tension. Could the excessive tension cause the exhaust cam to not rotate smoorthly and cause a kind of pseudo ratcheting action that causes the CAS to screetch intermittantly.

Looking for any advice. Thanks

[Paul.P]

I have heard from Gerald at GST that an incorrectly adjusted cambelt can make the cas noisy, so i advise checking the cambelt tension ?.