yeah, before starting a religious debate on pilots and levers, the first thing to do is to follow the maintenance manual. If you have a lycoming the valve wobble test should be a regular part of your vocabulary.
That wobble test is for older engines.
There are two documents that we need to refer to for this: SB388C...
http://www.lycoming.textron.com/support/publications/service-bulletins/pdfs/SB388C.pdf
...where we find this:
"TIME OF COMPLIANCE: Helicopter Engines – 300 hour intervals or earlier if valve sticking suspected.
All Other Engines – 400 hour intervals or earlier if valve sticking suspected until exhaust valve guides are replaced with guides made of improved material. (Refer to latest revision of Service Instruction No. 1485.)"
So now we need to take a look at SI 1485...
http://www.lycoming.textron.com/support/publications/service-instructions/pdfs/SI1485A.pdf
...where we see this:
"Improved exhaust valve guides were initially incorporated into some cylinder assemblies beginning in April 1996. Since March 1, 1998, all engines, cylinder kits and spare exhaust valve guides shipped from Lycoming contain the improved material.
Cylinder assemblies which incorporated the improved “Hi-Chrome” exhaust valve guides when the engine was shipped from Lycoming are identifiable by the letter “C” stamped inside a circle on the boss for the drain back fitting. The individual guides made with the improved material can be identified by a 5° chamfer at the top of the guide (See Figure 1).
Once guides made from the improved material are installed in all cylinders on the engine, it is no longer necessary to complete the mandatory 400 hour inspections specified in the latest revision of Service Bulletin No. 388. It is recommended that the inspection procedure from the latest revision of Service Bulletin No. 388 be completed at 1000 hours of operation or half way to the recommended TBO, whichever occurs first. (For recommended TBO, refer to the latest revision of Service Instruction No. 1009."
So they dropped the 400-hour requirement and suggest that you do the check at 1000 hours. We ran a lot of Lycomings, and once they changed that guide material, we didn't worry about any 1000 checks and we never had any valves burn, or guide issues at all. All of them made it to TBO without any valve issues.
Dan