Team Synergy Coatings: Automotive Coatings for Valves

Team Synergy Coatings Automotive Coatings The purpose behind coating a valve is to extend the part life and reduce friction. Because the do different functions, intake valves and exhaust valves are coated differently.

The intake valve seals the combustion chamber on the intake port side of the head. Prior to that, it is opening to allow air and fuel to enter the combustion chamber. Intake valves usually do not suffer as severely as exhaust valves which see combustion chamber temperatures; therefore, the primary concern is lubricating the valve stem and seat. Application of a dry film lubricant such as DFLC-402, DFLC-404, or DFLC-401 reduces the friction particularly in engines where oil flow is restricted to the head. The dry film takes over the bulk of the lubrication chore. It is still advisable to coat the face of the valve in the combustion chamber with TCB-101 or TCB-102 to help retain combustion chamber heat in the chamber. This also reduces the operating temperature of the valve. It reduces the temperature of the back of the valve so the incoming air fuel mix does not pick up as much heat from the valve. It is normally not necessary to thermal barrier coat the back of the valve.

On the exhaust side a more severe environment exists because the valve is seeing combustion chamber temperatures, which at this point on a normally aspirated engine, can easily be at 1,350oF (732oC); on certain engines this can run even higher. Coat the face of the valve with a thermal barrier (TCB-101or TCB-102) to reduce the heat that the valve absorbs. Then coat the back of the stem with a dry film lubricant (DFLC-402, DFLC-404 or DFLC-401). Again, it’s very critical on the exhaust valve stem because the heat can reduce the ability of oil to lubricate. Consequently, the permanently bonded, high pressure, high temperature lubricants work extremely well at reducing friction and wear on the valve and the guide. In some cases, it is advisable to coat the back of the exhaust valve (TCB-101or TCB-102) such as on a titanium valve where metal erosion is possible due to hot gas and flame passing over the raw titanium. On other valves it is still preferable to coat the back with the dry film (DFLC-4021, DFLC-404 or DFLC-401) to contribute to carbon shedding so as to not get a carbon build-up on the back of the valve which can create turbulence in the exhaust flow.

Also, by coating the back on both the intake and exhaust valve after all machine work is done, lubricant is permanently bonded to the areas that will contact the valve seat thus reducing wear in this area and creating a better long-term seal.

Team Synergy Coatings can increase the life and durability of these automotive and engine parts: