HPC offers two coatings for pistons and
valves that can be used together separately of each other based on needs and
some class regulations in racing. HPC's thermal barrier coating (TBC) is
applied to the combustion face of the piston and a wettable solid dry film (SDF)
applied to the skirt.
Probably no part of an engine undergoes greater thermal shock than pistons and
valves. Yet this has no effect on the bonding properties of HPC's TBC
which has the same coefficient of expansion as aluminum. Particulates are bonded
with an inorganic binder which is unaffected by petroleum products. With a
bond strength of 10,000 psi, this coating's non-porous ceramic matrix improves
flame travel and combustion efficiency as well as reduces oil temperature and
prevents carbon buildup. HPC's TBC process also prevents excessive heat
from reaching the piston rings reducing radial tension loss due to the ring
overheating. Thermal barrier coating is applied to the combustion face of the valve prevents
overheating of the exhaust valve and heat transfer from the intake valve to
incoming cool air and fuel, thus providing a denser air/fuel charge. The
process works equally well on both two-cycle and four-cycle pistons, and is
applicable to new and used parts.
is a solid dry film lubricant that is applied to the skirts of the piston to reduce friction and prevent scuffing.
This wettable matrix coating is a Molybdenum Disulfide based coating rather than
PTFE. Moly is a higher pressure lubricant and does not "cold
flow" under pressures exceeding 150,000 psi. Moly also attracts oil,
keeping an adequate film on the part unlike PTFE which sheds oil. HPC S06
reduces piston to cylinder wall friction by over 10-times!
HPC S-Series' lubricants are suspended in a thermosetting polymer binder which hardens during curing
providing a permanent lubricant unlike break-in Moly, graphite, and other sprays
bearings, rocker arms, valve stems, camshafts, gear drives, transmission and
differential gears, and other "wet" components are other excellent applications for HPC's S06 coating.
A valve spring's biggest enemy is
heat. Heat is generated in the spring from three sources. First by cycling the
spring through compression and extension. For example, try bending a paper
clip back and forth, you will feel it get hot at the flex point. Second is heat
generated by the friction between the coils on double and triple springs or the
spring and the dampener. Third is heat absorbed by the spring from the
cylinder head, especially the exhaust spring being right over the exhaust port.
Cooling is achieved from oil being splashed over the spring by the rocker arms.
Many coatings have been used on valve springs. Most are PTFE based coatings, and
this is fine for reducing friction between coils and dampeners, but oil will be
shed by the PTFE eliminating any cooling the spring may see. Our S01 Solid
Dry Film Lubricant coating is the answer. S01 not only acts as a superior
high pressure lubricant but also attracts oil like steel to a magnet.
Valve springs coated with S01 can retain their seat pressure up to three times
longer than uncoated valve springs.
Many camshaft manufacturers now offer coated valve springs in their line-up (we
should know, we coat many of them). But usually only their most radical
springs for all out competition are coated. However, street driven cars
see just as much benefit. By performance standards, a valve spring on a
daily driven car is worn out by 40,000 miles. At this point even though
the motor runs fine it will be down on peak horsepower and RPM capability due to
the spring's loss of tension. Remember, it is the cams job to open the
valve but the valve spring's job to close it at the right time. S01 is an
excellent choice for any motor being built and is very affordable.
here to read the performance technical
report on HPC valve spring coatings.
Other S01 Applications:
Stamped steel and ductile iron
Rod and main bearings
Manual transmission gears
Ring and pinion gears
For those applications where you want a
coating that sheds oil and other petroleum liquids, rather than retaining it,
HPC has developed the solid dry film coating, S02. A major component of this coating is
polytetrafluoroethylene (PTFE). This process
works well in eliminating exfoliation/corrosion and oxidation on zinc, aluminum,
and magnesium. S02 can be applied directly over more conventional pretreatments
such as anodizing, phosphating, and electroplating. It is a
black-pigmented coating with temperature stabilities from -100° F (-79° C) to
+700° F (371° C).