Hi Michael..Is this for an M20?..If it is check that you have measured them in the same place along thier length. The guides can be tapered by .000"-.003"..Diameter should be .624-.625" at the smaller end and .625"-.627" at the bigger end..
The largest size you have quoted is on 'top limit' or the 'upper limit'..that shouldn't cause you a problem, particularly if the guides are tapered and that is the larger end, as one end of the guide isn't pressed into the barrel anyway.
Clearance of the valve stem to guide after fitting and sizing to finished size should be .003"-.005" inlet and exhaust...Ian
email (option): ian@wright52.plus.com
Hi Michael..15.92mm is .6267" which is .0003"(.0076mm) under the upper permissible size of the larger end of the guide.
Whether that is correct depends on whether the guides do in fact have any taper on them.
If they don't that means a maximum interference fit of .0027" if the guide bore in the barrel is at the lower guide tolerance of .624". Possibly it may be a thou under that (.623") which would give an interference fit of .0037"
Unfortunately my information does not give the barrel guide bore sizes.
So first you need to determine whether the guides are tapered or not. If they are not you need to measure the guide bores in the barrel to determine how much fit you actually have.
Assuming a guide bore size of .623"-.624" in the barrel and a maximum guide size of .626" on the part of the guide that is pressed into the barrel (using original taper tolerances), then the standard fit would be .002"-.003".
You could be up to .0007" over this figure.
Before drawing any conclusions though I would first determine what the guides and guide bore are actually measuring up at...Ian
email (option): ian@wright52.plus.com
email (option): ahum@quicknet.nl
Have a look at my tip of Feb 28, 2012, to make installation easier...
email (option): viaconsu # planet dot nl