pistons

HPC Piston and Valve Coatings


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 lubricant (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 losses due to the ring overheating. TBC 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 2-cycle and 4-cycle pistons, and is applicable to new and used parts.

Our S01 dry film lubricant is applied to the skirt of the piston to reduce friction and prevent scuffing. Unlike other piston coatings S01 does not contain PTFE.  PTFE “cold flows” and “waxes” under extreme pressure and sheds oil away from the piston (the next time you pour cooking oil into a non-stick pan observe how it puddles up and does not “film” over the surface).  S01 attracts oil, thus keeping an adequate film on the part at all times.  And S01 is permanent, unlike the “break-in” coatings used by several companies.  S01 can also be applied to the stem of the valve to reduce friction and wear and connecting rod and main bearings are other excellent applications for HPC’s S01 coating.

We do not recommed any resizing of the cylinder bore or the ID of the valve guide to compensate for S01.  S01 thickness is 0.0007″ – 0.001″ and is a lubricant, just like oil.  Increasing bore diameters will just cause the piston or valve to be loose.  Take all measurements from the components before sending them to us for coating or finish the bores or guides to the piston or valve manufacturer’s recommendations.

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updated 07/05/00