Car Craft
Click here to find out more!

Camshaft Break-In Guide - How To Break In That Flat-Tappet Cam

By , Photography by

It's All About Oil
While flat-tappet cams and materials haven't changed much in the last 10 years, engine oil and other lubricants have mutated rapidly as the demands for improved power, emissions, fuel economy, and extended drain intervals have continued to escalate. Most car crafters are aware that OE demands for a reduction of zinc and phosphorous additives (commonly referred to as ZDDP, which is the abbreviation for zinc dialkyldithiophosphates*). Zinc and phosphorous are used as antiwear additives with calcium, sodium, and magnesium considered detergents, while molybdenum and boron are friction modifiers. The demands for lower concentrations of ZDDP occurred because it is inevitable that portions of oil vapor (including ZDDP) will easily enter the inlet system via the PCV system. Once combusted, the ZDDP eventually coats the precious metals in the catalytic converter, reducing its efficiency. The OEs requested a reduction in pre-1993 levels of 1,200 parts per million (ppm) of zinc and phosphorous to 800 ppm. The American Petroleum Institute (API) responded with the SM category that has recently evolved into the SN standard oil for new cars. The API SM standard almost immediately began causing cam lobe failures in engines running aggressive flat-tappet hydraulic camshafts, and it has become clear that this oil should not be used without some kind of additive during the critical break-in period. But even if a new camshaft survives initial break-in through the use of higher ZDDP content additives like GM's Engine Oil Supplement (EOS) or Red Line's Oil Additive, there are still long-term durability questions if the engine was treated to typical off-the-shelf API SM oil.

As a hedge against problems, many enthusiasts began using diesel oil with higher ZDDP levels. This is a solution, especially if you don't have access to specialty or specific break-in oil. Shell (and others) offers 10W-30 Rotella T diesel oil as opposed to the more traditional thick diesel engine oils. The best solution for breaking in a new flat- tappet camshaft that involves the least risk is to use the specifically blended break-in oils from companies such as Brad Penn, Comp Cams, Edelbrock, Joe Gibbs, Lucas, and Royal Purple. Break-in oils are blended with higher concentrations of ZDDP to accommodate the severe sliding friction present with a new cam and lifters. Since high detergent levels tend to clean the zinc and phosphorous from high-wear surfaces, evidence suggests the ideal blend for a break-in oil is sufficient levels of ZDDP combined with a lower detergent concentration. This allows the zinc and phosphorous to do their job.

Once the camshaft is fully broken in, the engine still needs sufficient antiwear protection beyond what API SM and SN oils can provide. Specialty oil from Comp Cams, Edelbrock, and Joe Gibbs or race oils from Amsoil, Red Line, and Quaker State offer critical antiwear advantages over API SM or SN oils, providing additional antiwear protection for flat-tappet cams and lifters. While these boutique blended oils cost more, they also offer an important level of insurance against losing a cam. Like those old commercials used to say: "All motor oils are not alike." Today, that statement has never been more accurate.

Enjoyed this Post? Subscribe to our RSS Feed, or use your favorite social media to recommend us to friends and colleagues!
0 comments
Car Craft