Roller Derby: How to Break In a Roller Camshaft

By now, it’s common practice (or should be) to use break-in oil with ZDDP or a zinc additive for a flat-tappet camshaft.

But what about roller cams? Any old oil will work for that, right?

According top engine builders, ring manufacturers, and cam grinders, the answer is no. And the reason is pretty simple.

While the rings need to be seated in a roller, an oil that “wears-in” the rings will create a lot of fine metal particulate, and that particulate is a killer for your roller cam. According to Timken, the number-one reason for premature roller bearing failure is particulate contamination. An engine creates more particulate wear metal during break-in than at any other time. In fact the “normal” wear metals for a new engine are up to four times higher than after a engine has finished breaking-in—hence the term “breaking-in.”

So what does this have to do with motor oil?

Quite simply, not all break-in oils are the same. Some break-in oils are designed to accelerate the break-in process, and as a result, these oils generate higher levels of wear metal—bad news for your roller bearings. Other oils are friction modified. The added slipperiness of these oils can prevent the rings from seating properly

Striking the right balance is critical.

Driven BR break-in oil, for example, was formulated to help Joe Gibbs Racing with its engine program. Mark Cronquist, Chief Engineer Builder at Joe Gibbs Racing, says the break-in oil has two jobs: protect the valvetrain and not hinder ring seal.

“With a compacted graphite block and tool steel rings, the materials are very hard, so if the oil is too slippery, the rings won’t seat properly,” Cronquist said. “We still have a valvetrain with roller bearings that need protection as well, so the break-in oil features a high anti-wear formulation without friction modifiers to chemically assist the ring sealing. This strategy reduces the amount of wear metals created during break-in, and that protects the roller bearings in the valvetrain.”

Another aspect of roller cam break-in to consider is the high spring pressures and contact loads the cam, lifters, pushrods, and rockers see. While these loads would spell death to a flat-tappet cam, the high ZDDP anti-wear package of a break-in oil also protects these components during that critical break-in period.

Think of a break-in oil like a primer. Putting down primer before you paint establishes a uniform coating to build from, and that is exactly what a break-in oil does—it establishes a uniform anti-wear film that provides the foundation for protection. Just like a thick coat of primer smoothes out a surface, a properly formulated break-in oil does the same thing. The protective layer of ZDDP anti-wear film smoothes out the peaks and valleys that comprise the microscopic surfaces on the roller wheels and needle bearings. A smooth surface enables greater load carrying with less fatigue.

The more aggressive the valvetrain, the more critical these details become.

“It is hard to fall off the bottom of the mountain,” said Brian Reese from COMP Cams. “The more aggressive the valvetrain is in terms of lift, duration, and spring pressure, the less margin of error you have. The little details become critical.”

According to Reese, using a break-in oil is just part of the equation.

“We are seeing a trend away from flat-tappet engines to avoid the oil issues related to flat tappet cams, but just because you have a roller cam does not mean that it does not have to be broken in properly,” Reese said. “NASCAR level engine programs like Joe Gibbs Racing are still doing a 30-minute break-in on their roller cam engines because they have learned the hard way what happens when they don’t.”

Reese says improper break-in will catch up with you eventually.

“If you get the break-in wrong with a flat tappet cam, it dies right in front of your face,” he said. “If you get the break-in wrong with a roller cam, it may not die until several thousands of miles down the road, but the problem began at break-in.”

Here are a few break-in tips from the experts:

1. Wash off the rust preventative coating that is on the parts prior to installation. Parts are shipped with a preventative coating, and it needs to be removed for lubricants to function at maximum efficiency.
2. Apply a calcium-sulfonate grease instead of ZDDP before assembly. While ZDDP is critical in the break-in process, it is not the best assembly lube. After cleaning the camshaft and lifters, apply calcium-sulfonate for protection and lasting lubrication during initial start-up. Then, soak your roller lifters in break-in oil.
3. Use a finer micron filter during break-in.
4. Prime the pump before firing the engine. This ensures a critical supply of oil to the cam and lifters at initial start-up.
5. Do not idle the engine. Bring the engine up to 2,500 rpm and vary the speed by a few hundred rpm for 20-30 minutes.
6. After a 30-minute break-in, change the oil filter. At this point, you have removed all the larger particles that could cause problems and you can start upping the flow rate of your filter.
7. Change the oil and filter after initial break-in. Most of the wear metals created by an engine occur during the first hour of operation.

By properly breaking in your roller camshaft, you’ll ensure maximum performance and long life.