Bothersome engine noise

[Jon Eckman]

There is a sporadic metallic ticking that follows with engine revs in my more or less stock '66 twin cam, which seems to be coming from the upper end of the motor. Pulled the plug wires one at a time and the ticking didn't stop. A machine shop familiar with Lotus heads took it apart and did a valve job and changed the cam bearings (great oil pressure now!) but did not see anything wrong with it otherwise. Reinstalled the head, same ticking present. The local shop that pulled the head and put it back together tried various adjustments to the timing chain tension with no effect. They stethoscoped all around the motor and noticed the loudest sound coming from the front of the exhaust cam area and wondered if a worn sprocket and/or chain could be causing the ticking. Can anyone shed any light on this condition?

[promotor]

Most likely to be loose cam follower buckets - either the bucket sleeves or cam followers would be worn in that scenario.

That's my two pence worth and I'm sticking to it!