PROFESSOR OVERDRIVE ® Professor Overdrive and Summit’s team of tech experts are hard at work in the lab solving your muffler mysteries, radiator riddles, and piston predicaments! Gather your vehicle’s make/model/year, engine, transmission, and driveline details, and send your tech questions to: Ask Professor Overdrive c/o Summit Racing Equipment PO Box 909 Akron, OH 44309-0909 Visit the online Help Center at SummitRacing.com, where you can browse our technical resource archives and ask questions. Still need help? Call 1-800-230-3030 to speak directly with one of our knowledgeable sales experts. 254 WARNING: For Proposition 65 information, see p. 183 Some parts are not legal for sale or use in California or other states with similar laws/regulations—see p. 183 for details. THIS EDITION: Cam Care and Primary Wiring Flat Tappet Camshaft Break-In When installing a new flat-tappet cam, it’s essential to use a break-in oil containing ZDDP, a compound that forms a protective film on metal surfaces, preventing harmful metal- to-metal contact between the cam lobe and lifter. Many modern engine oils are formulated with reduced levels of anti-wear additives like zinc and phosphorus, which are vital for camshaft break-in and longevity. It is important to follow the break-in procedure specified by your camshaft manufacturer. Although the steps may vary slightly by brand, they generally adhere to the same process: • Liberally coat the cam lobes, distributor gear, and lifters with assembly lube, which is usually supplied with new camshafts. • When using dual valve springs, remove the inner spring during break-in, or if you have a high- load single spring, use a lighter break-in spring. While this is more work, it’s easier than dealing with cam and lifter failure. • After installing the cam in the engine block, pour a ZDDP additive over the cam lobes. Ensure the additive also covers the lifter bores, then install the lifters and valvetrain. • Fill your crankcase with non-detergent race-only conventional motor oil. Avoid using multi-viscosity or synthetic oils during the initial break-in, as they can contain detergents that may lead to shearing of the oil film and result in destructive metal-to-metal contact. • Before initial start-up, prime the engine oiling system with a priming tool. When the engine is properly primed, you should see oil spouting from the pushrod ends at the rocker arm pushrod seats. Avoid pre-lubing the engine by cranking it over with the starter motor, as this “dry cranking” will wipe off the pre-lubricants and can lead to metal-to-metal contact. • As soon as the engine fires, rev it to 2,000-2,500 rpm, maintaining that range during the first 20-30 minutes of operation, periodically varying rpm. After this break-in period, change the oil and filter to remove any contaminants that may have accumulated in the engine. Reinstall the inner valve springs, if needed. • Always use oil with a ZDDP additive for subsequent oil changes to ensure proper lubrication throughout the cam’s lifespan. Understanding Wire Types Different types of electrical wires are utilized across various industries. As you can imagine, using the incorrect type of wire in an automotive or marine low-voltage DC electrical system can result in serious failure. Not all wires are designed to carry high current, withstand extreme temperatures and vibration, and resist chemicals in the same way that automotive wire is. For example, speaker wire is not designed to carry high current, withstand extreme temperatures, or resist chemicals; instead, it is rated in ohms. Similarly, Romex home wiring is intended for less flexibility, lower heat resistance, and limited chemical resistance compared to automotive wire. Therefore, the use of both speaker and home wire must be avoided in vehicles. To help you choose the best wire for your project, here is a brief overview of three common wire types used in the transportation industry: • GPT wire is a single-conductor accessory wire that features a stranded copper conductor and polyvinyl chloride (PVC) insulation. This wire is flexible, oil- and grease-resistant, and carries a temperature range of -40°F to 176°F. • TXL wire is a thin-walled, lightweight single- conductor wire with cross-linked polyethylene (XLPE) insulation. It’s ideal for tight spaces and has excellent flexibility. It’s resistant to abrasion and chemicals, and has a temperature range of -40°F to 257°F. • SXL wire is an automotive primary wire designed for harsh, high-heat environments, like engine compartments. It features stranded bare copper with a cross-linked polyethylene (XLPE) insulation that resists abrasion, oil, and gas, and carries a temperature range of -60°F to 257°F. Additionally, tinned wire can be used with any of the variants above and is generally rated for marine use. It features a tin coating that prevents oxidation and corrosion, making it a good choice in humid and corrosive environments, such as around saltwater. Additionally, tinned wire offers improved solderability. Shielded wire is used in ECU wiring to prevent external electromagnetic interference (EMI) to signal-carrying conductors. It’s ideal for critical engine sensors such as camshaft, crankshaft, ignition, and more. Scan here for more articles on camshaft care! For handy tech articles, how-tos, and product installs, check out our blog at OnAllCylinders.com! Find more helpful tips from the Professor in these sections: AIR & FUEL DELIVERY: External Fuel Pump Mounting FITTINGS & HOSES: AN to Inch Conversions CAMS & VALVETRAIN: Flat Tappet Cam Lubrication COOLING: Short vs. Long Chevy Water Pumps TRANSMISSION & DRIVETRAIN: Finding Converter Bolt Patterns WHEELS & TIRES: Buying Custom Wheels
