THE SHOP

Performance & Hotrod Business May '14

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May 2014 n Performance & Hotrod Business n 57 valve faces and exhaust ports • Thermal barrier coatings for exhaust manifolds Thermal barrier coatings (typically involving a ceramic formula) provide what the term implies: a heat barrier. When applied to piston domes, this not only helps to protect the piston from excessive heat (generated via forced induction, espe- cially in turbo setups), but this coating also helps to improve horsepower. More specifically, it enhances combus- tion efficiency, since the heat that would otherwise be soaked into the piston and combustion chamber is now better-con- tained and aids in the more-efficient burn- ing of the fuel/air mixture. The same holds true for thermal barrier coating applied to the faces of the exhaust valves and inside the cylinder head exhaust ports. Instead of losing heat (via soak), the combustion heat is "contained" and scoots out instead of hanging around and soak- ing into the pistons, valves and heads. Not only is this a heat-protective coating, but because of the thermal efficiency, it may also (depending on other factors) provide a slight increase in power. Anti-friction coatings (typically a moly-based formula) can be applied to a variety of surfaces, most specifically to cam, rod and main bearings and piston skirts. While this won't provide addi- tional power, it's a protective film that helps reduce frictional losses and extends component life, primarily during cold startups and during high-temp/high-stress environments (when you're really ham- mering it). By the way, specialty coatings are also available for supercharger and turbocharger components, which may provide added efficiency as well as extending durability. If you're interested in enhancing these units, contact both the forced induction maker and the coating specialists. They can advise you regarding availability and benefits, and what coatings (if any) make the most sense for your application. Examples of coating services include Swain Tech Coatings, Polydyn and Calico. • Specialty coatings (thermal barrier and anti-friction) • Connecting rods (switch to forged in place of cast iron or powdered-metal cast) • Connecting rod bolts (switching to higher tensile strength aftermarket bolts is always a good idea) • Crankshaft (switch to forged in place of cast) • Double-keyed crank snout • Steel/high performance crank damper • Converting to a keyed damper/pulley on an LS press-fit pulley crank • Cylinder head gaskets (switch to MLS in place of composite) • Cylinder head studs (in place of bolts) • Main caps (billet steel in place of cast iron or powdered metal) • Main cap studs or bolts (using higher tensile strength) • Main cap girdle (depending on engine) • Valves (potential upgrade to higher- quality stainless valves and/or Inconel for exhaust valves) • Higher-rate/more durable valve springs • Rocker arms (more durable aftermar- ket full-rollers) • Cooling system (make sure the exist- ing cooling system is clean and functions properly; and potential need for more effi- cient water pump and radiator, especially if using an intercooler) Specialty Coating Enhancements While some (primarily non-engine builders) may scoff at the usefulness of specialty engine coatings, there are distinct advantages that various coatings offer to improve either durability or performance, or both. While a wide range of specialized coat- ings are available to suit a variety of tasks, with regard to coatings that suit forced induction setups, here we're focusing on the following coatings: • Thermal barrier coating for piston domes • Thermal barrier coating for combus- tion chambers • Moly (anti-friction) coatings for pis- ton skirts and bearings • Thermal barrier coatings for exhaust Mike Mavrigian has written thou- sands of technical articles over the past 30 years for a variety of auto- motive publications, in addition to writing nine automotive technical books for four different publish- ers. Mike also owns and operates Birchwood Automotive in Creston, Ohio, where he builds custom engines, street rods and per- forms vehicle restorations. Mike can be reached at 330-435-6347 or birchwdag@frontier.com. Birch- wood's website is www.birchwoodautomotive.com Strong aftermarket forged connect- ing rods are far better able to with- stand high stresses as opposed to OE cast or powdered metal rods. FI13 Increasing cylinder pressure makes the engine work harder and plac- es additional stress on the rotating and reciprocating assemblies. A complete bottom end kit is available from several crank makers that will include appropriate grades of crankshaft, rods, pistons, rings and bearings. (Courtesy Scat) PHBMAY.indd 57 4/2/14 11:56 AM

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