Sorry in advance for going over a fairly common topic.
Checking my valve clearances I ended up with:
Front Cyl:
Exhaust:
Opener: 0.003-0.0035"
Closer: 0.0025-0.003"
Intake:
Opener: 0.004"
Closer: 0.002"
Vertical Cyl:
Intake:
Opener: 0.0035"
Closer: 0.0025"
Exhaust:
Opener: 0.0035"
Closer: 0.0025"
Is 0.0025-0.003" too loose for the closers?
Should I sand down the opener shims on the front exhaust and vertical intake/exhaust to get 0.004"?
Exhaust openers are usually. 005 recommended due to more heat. I would replace the closers.
Get a size bigger, take both opener rocker arms and shift them over, take belts off, and spin the cams for drag. Sand slowly until drag is gone. Do one closer at a time so you can be sure the drag is associated with the closer you are working on.
Lastly, once you get no drag, spin the shim at 10 deg increments and spin the cam again to make sure you don't have highspots to create drag.
What about replacing the collets with new or MBP to take up some of the closer slack?
That is an option but realize that the stock shims to tend to mushroom. The clearance might change down the road again faster than expected. Obviously the profile of the MBP will be slightly different.
You're right though the MBP do take a little more space. You could close the gap that way.