Blocks And Sumps
Exotic hardware—such as aluminum blocks and dry sump oil systems—were once the exclusive territory of full-tilt race cars, but are now readily accessible to the sportsman racer. Consequently, it's important to know how this exotic hardware affects oil selection. "A 0.0025-inch main bearing clearance in an aluminum block is probably closer to .0040 when the engine is hot, so aluminum blocks tend to require higher viscosity oils than iron block engines with the same clearance. An iron block engine with 0.0025 main bearing can run a synthetic 10W-30, but an aluminum block with the same clearance will need to run either a synthetic 10W-40 or a conventional 20W-50," Lake explains. "Keep in mind that you can run one viscosity grade lower in a synthetic compared to a conventional oil because of the better temperature-to-viscosity characteristics of a synthetic. In regards to a dry sump vs. wet sump engine, heat is the determining factor. Most wet sump engines run hotter than dry sump engines, so wet sump engines typically run thicker oils. A conventional 20W-50 is a common oil for a wet sump race engine. Since wet sump engines run hotter than dry sump engines, it is better to run a synthetic oil in a wet sump engine. The better start-up flow properties of the synthetic help reduce start up wear, and the higher viscosity index of the synthetic provides the required high-temperature protection. A 10W-40 synthetic is an excellent choice for a dry sump race engine. Since dry sump engines tend to run cooler than wet sump engines due to increased oil volume, decreased windage and remote cooling, dry sump engines can run lower viscosity oils. This helps with priming the system, reducing start-up wear, and reducing heat generation."
An engine that runs on the street and at the track provides a unique set of challenges for oil designers. Race only oils give up extended drain intervals in return for increased horsepower via exotic friction modifiers. Street/strip motor oils that offer 3,000- to 7,500-mile drain intervals trade away some friction modifiers in order to meet the varied needs of a street/strip engine. Since street/strip engines will typically see longer drain intervals than a race-only engine, the motor oil must be designed to handle longer drain intervals while still providing excellent anti-wear protection. "Don't forget that street/strip cars are not typically daily drivers, so these engines see longer periods of storage than daily drivers. As a result, storage protection and start-up wear are a bigger concern," says Lake. "Consequently, a street/strip oil must take into account start-up protection, storage protection, anti-wear protection and extended drain intervals. Chemically, street/strip oils are formulated differently to handle all of these needs. When considering all of these various applications, from break-in to racing to street/strip, it is important to remember that it is hard to fall off the bottom of a mountain, but your margin for error is narrow as you near the top. At low levels of performance, many of these factors may seem like overkill, but at higher levels of performance, these factors are your lifeline."
In addition to offering a full line of street and race motor oils, Driven has also developed a full range of lubricants to assist in the engine assembly process. "Since initial break-in is the most critical time in an engine's life, having the proper assembly lubricants on vital wear components is just as critical. Over the last 13 years, Driven has worked with engine parts manufacturers, JGR and select professional engine builders to create a complete engine assembly and break-in package," says Lake. "Products like our Engine Assembly grease and HVL assembly oil provide the correct additives and viscosity requirements for the various parts in an engine. The Driven Engine Assembly grease provides anti-wear protection for cams, lifters, pushrods and distributor gears. Likewise, Driven's HVL assembly oil provides anti-scuff lubricity for bearings, wristpins, and piston skirts. Finally, Driven's BR series of break-in oils can be used to soak roller lifters and shaft-mount rocker arms as well as wetting cylinder walls. As a whole, this system of lubricants provides a carefully coordinated chemistry that is proven to protect and deliver consistent break-in performance."