CHOOSING THE RIGHT OIL FOR FLAT TAPPET CAM BREAK-IN
All oils are not created equal.
by Mike Mavrigian
photos by author
Avoiding flat tappet cam failure can be as simple as using the correct oil during break-in.
Chances are you’ve run into this problem first-hand, or know a builder who has shared his horror stories. We’re talking about flat tappet camshaft failures during break-in. In recent years, there has been a rash of cam problems and, in too many cases, the cam makers have unjustifiably shouldered the blame. The problem does not lie with the camshafts. Rather, the problem is caused by the engine oil used during break-in.
Because of mandates by the EPA, a vital element of the oil mix, commonly called ZDDP, has been drastically reduced in standard engine oils that are intended for the late-model street vehicle. In short, if the oil doesn’t contain enough ZDDP, it doesn’t offer adequate anti-scuff protection for the initial break-in of flat tappet cams. Let’s face it, when a customer’s brand new cam gets wiped out through no fault of yours, life can be frustrating to say the least.
ZDDP (zinc dialkyl dithio phosphate) is an anti-wear and antioxidant, initially developed in 1930 as an antioxidant to prevent engine bearing corrosion. ZDDP also features excellent anti-scuff and anti-wear properties. In the 1960s, ZDDP featured a zinc level of 0.07 percent when high-performance flat tappet camshafts were common. At that time, new camshafts were phosphate coated as well and the combination worked well to protect new camshafts and lifters from premature wear, especially during break-in.
In the 1970s, zinc levels increased to 0.09 percent because ZDDP is an excellent antioxidant. As engines became more powerful, oil recipes changed as well, becoming more complex with more functional additives such as friction modifiers, antioxidants, detergents, etc. Friction modifiers gained further popularity to aid fuel economy, with zinc content increasing to 0.2 percent in the 1980s and early 1990s.
By the way, ZDDP is only one acronym for this anti-wear/antioxidant content. It’s also referred to as ZDP or ZZDP. Why? Who knows and who cares?
So if ZDDP is so cool, why has it been reduced to the point where it’s causing flat tappet cam problems? Phosphorous is a well-known contamination source for catalytic converters (some refer to it as converter poison). The limit for phosphorous dropped to 0.10 percent, which means that the zinc level dropped as well. In 2004, with Tier 2 emissions standards, OEM warranties changed to 10 year/100,000 miles, and phosphorous dropped again to 0.08 percent, with zinc down to 0.09 percent.
Engine oils, in general, are vastly superior to oils made in the past, a major factor responsible for some engines being able to last for 250,000 miles or so. Also, today’s metallurgy is better. The issue here is high-performance flat tappet cam lobe wear during the break-in period. Aggressive cams with high spring loads compound the problem. This issue does not affect roller cams, since there’s no scuff wear issue with rollers.
In a nutshell, whether in a direct or indirect manner, the EPA has told the oil makers to ignore older (i.e. flat tappet cam) engines and to make an oil that avoids converter damage (thereby reducing emissions) in late model cars, and the hell with the restoration and performance market. Marie Antoinette once told the French peasants to eat cake. The EPA has basically told car guys to fend for themselves. Either expression is offensive as hell.
We could say that this entire problem could have been avoided if we (the engine community) were properly informed about the change in oil make-up. In that case, we could have made a point to search for specific break-in oils that did contain adequate ZDDP levels. Instead, many of us learned the hard way by needlessly wiping out otherwise perfectly good camshafts during break-in runs. At this point, it’s a case of too little too late. Let’s all send a big fat thank you to the government and the major oil marketing companies for making our lives a living hell.
WHAT’S THE ANSWER?
To avoid flat-tappet cam lobe damage during break-in, naturally you must continue to apply the specific cam lobe and lifter assembly lube that’s recommended by the cam maker, plus you can install low-rate valve springs for the break-in.
In addition, you can and should use one of the few currently-available engine oils that do contain sufficient ZDDP. These oils are available, but you need to remember to specifically purchase these oils and dedicate them for flat tappet cam break-ins.
Engine oils that are specifically designed for use in diesel applications will usually feature more zinc than passenger car gas engine oils. However, diesel engines are coming under greater scrutiny as well in an effort to further reduce emissions nationwide. So, while a dedicated diesel oil may be better than a passenger gas engine oil in terms of zinc content, you can’t automatically assume that any diesel oil contains enough ZDDP to protect a new flat tappet cam.
According to the tech boys at Crane Cams, oils that they are currently aware of that are compatible for flat tappet cam break-in include Shell Rotella T, Chevron Delo 400 and Mobil DELVAC. All three of these are classified as diesel oils. Crane did note that Rotella T has apparently been modified with a slight cutback on zinc (rumor has it that zinc was reduced from 1,400 ppm to 1,200 ppm), but that should not be enough to cause problems.
I have heard other unsubstantiated rumors, however, that Rotella’s zinc has more recently been further reduced to 800 ppm (and possibly even further), but we could not get that rumor qualified in time for this article. Crane did note that if a questionable oil is to be used (where the user is not sure of the ZDDP content), a friction modifier such as GM EOS should be added for break-in. However, no additional friction modifier additives should be added to a break-in oil that is documented as flat-tappet-break-in safe.
When we spoke with the folks at Redline, they did mention that while they do not currently offer a break-in oil, they do have plans to introduce a ZDDP additive in the future. So, nothing at the moment, but possibly down the road.
A call to the tech department at Valvoline corrected an issue that is currently misunderstood among some builders. While Valvoline does offer an Off Road 20W-50, that is not the oil recommended for flat tappet cam break-in. Instead, they advised using their VR1 Racing Oil, an SM-rated oil that features 1,300 ppm of zinc. They also noted that while a common misconception is that SM-rated oils are considered unacceptable for this application, that this is simply not the case.
Castrol has recently introduced its new CASTROL SYNTEC 20W-50, which reportedly “contains increased zinc levels for extra engine wear prevention … uses proprietary additives and base oils to reduce metal-on-metal contact of aging engine parts … engineered to increase wear protection for classic cars with flat tappet camshafts.” While this oil may be fine and dandy for day-to-day use in flat-tappet engines, because it is a synthetic oil, in good conscience we can’t recommend it specifically for break-in since it’s never a good idea to break in any engine (flat tappet or roller) with a too-slippery synthetic oil with regard to ring seating and flat tappet lifter rotation.
Lake Speed Jr. at Joe Gibbs Driven noted that they developed their dedicated BR break-in oil specifically to meet the needs of flat-tappet cam applications, which contains a whopping 2,800 ppm zinc. Speed told us that they developed this oil in order to be able to use the same oil for break-in and for complete dyno sessions. Gibbs also offers a special Assembly Grease for lobe and lifter lube during assembly.
Dick Glady, a highly respected racing oil expert who has worked in the racing oil industry for decades, of American Refining Group, makers of Brad Penn Racing oils, informed us that their entire line of racing oils has never been reduced of its zinc content. All of their racing oils still contain favorable levels of zinc and contain special cuts that enhance oil cling and anti-scuff properties.
While many of American Refining Group’s race engine customers use its 20W-50 racing oil for break-in, dyno and competition use, the company has also introduced a dedicated break-in oil for flat tappet cam engines called Penn Grade 1. This is a straight 30W oil with high levels of zinc and special anti-scuff properties, and is specially formulated to promote proper piston ring seating during break-in as well. This is definitely a premium break-in oil.
To summarize, while there are a handful of engine oils out there that are reportedly safe to use for flat tappet cam break-in, the select few for which we have definite approval include the Brad Penn Penn Grade 1, the Joe Gibbs MicroZol BR and Valvoline’s VR1 Racing oils. Coat the lobes and lifter faces with the cam maker’s approved assembly lube, use one of these oils, and you should be good to go.