Race Rings Reducing friction and weight while maintaining needed sealing presents challenges to pro race engine builders. by Mike Mavrigian Evolutionary and revolutionary changes are constantly taking place with regard to pro-racing piston ring applications. To gain a bit of insight in terms of what’s happening at the moment, I spoke to two leading sources, [...]
Custom pistons are available in any configuration, but knowing what’s needed to order them requires careful measurement and sound decisions. Once the data sheet is accurately completed, your order begins to forge blank slugs. Initial machining begins with pin bore placement. Here the rod small end passage is machined, based on your reported small end [...]
MAKE A MOLD Simone also told me that Diamond Racing now offers a very cool epoxy chamber mold kit that can absolutely save the day in terms of what your application demands. The kit (an A-B pair of epoxy cans, a mixing stick, nitrile gloves and a spark plug hole plug) it sells for a [...]
ORDERING CUSTOM PISTONS When an off-the-shelf slug won’t do, you need to turn to the custom boys. by Mike Mavrigian photos by author Need a set of custom slugs to work with your new heads and your bore/stroke combo? A ton of info is required before a piston manufacturer can begin to execute your order. [...]
The hot honing unit is plumbed to the block on the honing machine. The intention is to simulate engine operating temperature (at least in terms of coolant temperature) during honing. THERMAL CONSIDERATIONS DURING HONING Another aspect of obtaining a bore that will remain as true as possible during engine operation involves heat. Consider that although [...]
CLAMP LOAD Bore distortion is generally directly related to clamp load. The clamp load must restrain combustion lift-off force and still provide adequate force for the gasket to do its job. Additional clamp load generally only leads to additional bore distortion. In other words, tightening head fasteners beyond the recommended specification will only hurt. The [...]
CYLINDER BORE DISTORTION Understanding static and dynamic cylinder bore shape. by Mike Mavrigian All illustrations courtesy Mahle-Clevi This stress graph illustrates how a cylinder bore may be distorted from round to out-of-round as a result of head fastener loads. This dimensional “isometric” view further illustrates static dimensional shift that can occur from cylinder head installation. [...]
ANTI-FRICTION AND OIL MANAGEMENT COATINGS Anti-friction coatings (which would be applied to components such as bearings and piston skirts) not only provide a much lower coefficient of friction (when and if physical contact between two moving surfaces takes place), but also serve to retain surface oil between moving parts, which is exactly what you’d want [...]
Bearings may be sent to coaters for moly-graphite treatment. The buildup of anti-friction coating is so minute that additional clearance compensation isn’t usually required. Cam bearings (such as these from Dart) are available pre-coated, or you can send your cam bearings out for coating. If you send bearings out for coating, don’t forget the thrust [...]
Engine Coatings A new look at this broadly-accepted practice by Mike Mavrigian photos by author Engine bearings are now available already coated from various bearing manufacturers. Clevite uses a polymer-based moly-graphite coating. Specialty coatings for performance engine components have been on the scene for a number of years, and have definitely transitioned from the “I [...]
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