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

Oil Test Results
The following chart contains results from 10 different oil samples sent to Polaris Laboratories for additive testing. Polaris Labs offers a very affordable single sample test for $22 that will deliver not only the metals listed in the chart below but also contaminant and wear metal results that will quickly present an accurate picture of contaminant issues inside your engine. This is also a great test before buying a used engine or car. It took less than a week to obtain results.

Current API SM and SN oil limit ZDDP (zinc and phosphorous) levels to 800 ppm. While ZDDP break-in level recommendations for flat-tappet camshafts vary widely, it appears that concentrations of around 1,500 ppm or above are appropriate, and as you can see from our testing, most of the break-in oils achieve that level. Substantially higher levels of antiwear agents do not necessarily guarantee reduced wear. Once the engine is sufficiently broken in, specialty oils for flat-tappet camshafts with ZDDP levels of roughly 1,200 ppm or higher are acceptable. Note that we also tested an older Mobil 1 API SJ oil, and the zinc and phosphorous were right around 1,300 ppm. We did not include all the results that Polaris delivered, but we did list calcium, which is a detergent additive. According to Lake Speed Jr. from Joe Gibbs Racing, reducing detergent levels for break-in oil allows the zinc and phosphorous to remain in place in high-friction applications such as the interface between the camshaft and the lifter. Normal high detergent concentrations do a great job of cleaning, which unfortunately also removes portions of the protective ZDDP layer. This is why Joe Gibbs reduces the percentage of detergents in its break-in oil.

Also note that we tested both new Royal Purple break-in oil and the oil we drained from our small-block with the failed camshaft. The zinc and phosphorous levels were slightly lower than we expected, as were the levels in Brad Penn, especially when combined with higher levels of detergent. In the Royal Purple used oil sample, the phosphorous level was 920 ppm, which is only about 15 percent above SM 800 ppm standard. Conversely, the Lucas Break-In SAE 30 pegged the zinc-o-meter with a 6,400-ppm count.