Rottler SG7, Operation And Maintenance Manual, Page: 70 / 102

Section 8 Machine Parts SG7 Manual
www.rottlermfg.com
8-3
Carbide Pilots
See Carbide Pilot catalog for a complete list of Pilots available.
Rottler Solid Fixed Carbide Pilots are manufactured from fine grain sintered tungsten carbide and are
ground to a very high degree of accuracy, straightness and surface finish - designed for a life time of
precision machining!
The part number of the pilot represents the actual diameter in metric of the straight/parallel part of the
pilot where the pilot fits into the valve guide.
For example:
UCP0700 means that the diameter of the part of the pilot that goes into the valve guide is 7.00mm
(0.2756”)
UCP1270 means that the diameter of the part of the pilot that goes into the valve guide is 12.70mm
(0.5000”)
Pilots are available in increments of .01mm (0.0004”). Normally, a small amount of clearance approx
.01mm (0.0004”) is required between the pilot and the valve guide.
Most new valve guides are manufactured to a nominal size and the valve stem diameters are
manufactured to be smaller than the nominal size to allow clearance for heat expansion of the valve
stem when the engine is operating. For example: a 7mm valve guide has an internal diameter of exactly
7.00mm (.2756”) The valve stem diameter of the intake valve is 6.98mm (.2748”) and the exhaust is
6.96mm (.2740”). In order for the pilot to fit most all valve guides, the first choice could be UCP0699 to
give .01mm (0.0004”) clearance. If the valve guide is used and has some wear, then the second choice of
pilot could be UCP0700(0.2756”).
Rottler makes 3 sizes of shanks of pilots:
6.00mm (0.2362”) for small valves guides 6mm (0.236”) and below. The part number for these pilots is
UCPM.
0.375” (9.52mm) for common size valve guides, 6-14mm (.236-.625”). The part number for these pilots is
UCP.
20mm (0.7874mm) for large valve guides for SG8M0A machine. These pilots are made to order
specifications.