Also
Take a long screwdriver and touch the end to various (safe not spinning) parts of the engine while it is making the noise and put your ear on the other end. This works like a stethoscope to help determine where the noise is coming from.

It could be a valve lifter or in the worst case a rod that is knocking.
Is the noise a click click sound or a bang bang sound?
How is the oil pressure? At idle and under driving load.
How high is the oil level?
What kind and viscosity is the oil being used?

__________________
"I have no convictions ... I blow with the wind, and the prevailing wind happens to be from Vichy"

Current
Monika '74 450 SL
BrownHilda '79 280SL
FoxyCleopatra '99 Chevy Suburban
Scarlett 2014 Jeep Cherokee
Krystal 2004 Volvo S60
Gone
'74 Jeep CJ5
'97 Jeep ZJ Laredo
Rudolf ‘86 300SDL
Bruno '81 300SD
Fritzi '84 BMW
'92 Subaru
'96 Impala SS
'71 Buick GS conv
'67 GTO conv
'63 Corvair conv
'57 Nomad