Flat-Tappet Camshafts - The Break-In Blues

For long-term protection of your flat-tappet camshaft and the rest of your race engine, you might consider Quaker State's new Q Racing line of synthetic oils. Developed through Quaker State's consultation with top Nextel Cup teams (which also run flat-tappet cams), Q Racing oil has the advantage in that it isn't meant for over-the-road cars. Instead, it is designed specifically for the needs of race engines. "Instead of just putting zinc back in," says Ferner, "we tried to come up with the best combination of all the individual additives. Besides being able to include all the zinc we thought was necessary, the oil provides maximum protection at minimum viscosity to help with power and includes special antifoaming agents because these engines see rpm levels that can be considered extreme."

Currently, Q Racing oils aren't carried in most stores because they aren't intended for road cars. You can find out where to purchase the products through Quaker State's distributor network by calling (800) 237-8645 or visiting www.qpower.com.

The first steps of the camshaft break-in process actually begin before the cam is assembled into the block. The best way to protect the cam and lifters during the critical first few minutes of operation is to make sure they are properly lubricated. The cam and lifters must be properly lubricated with a good lubricant that is slick and sticky enough to not wipe off after the first pass and will protect the cam during the first few revolutions until the oil pump can pressurize the system and take over. This is necessary even if you spin the oil pump to pressurize the oiling system before cranking the engine.

What you choose to lubricate the cam and lifters is important. Motor oil is better than nothing, but it is really too thin and is likely to drip off the cam and into the oil pan before you have even completed the engine build. Most camshaft manufacturers recommend moly-based lubricants or have their own blends. Assembly lubricants have a much greater viscosity and are designed to stick to the cam and not wipe off easily. You may also want to spray on a coat of dry silicone lubricant as a basecoat before applying the assembly lubricant. It simply provides another level of protection.

Flat-tappet lifter design is old technology, but that doesn't mean manufacturers haven't updated the components along the way. In the case of camshafts, most racers these days use cams that have been nitrided. The nitriding process hardens the outside surface of the camshaft and makes the lobes slicker to improve efficiency and durability. The process adds a little money to the cost of the cam, but few experienced engine builders would tell you it isn't worth it.

You can also find performance-oriented flat-tappet lifters that can provide a little extra security. When running a flat-tappet valvetrain in a modern race engine, the only friction surface that doesn't receive direct oiling is the contact area between the bottom end of the lifter and the cam lobe. That, however, has changed with the advent of lifters with EDM oiling holes cut into the lifter's face. This hole provides a steady stream of pressurized oil at the point of contact between the camshaft and lifter, so less oil volume is required to provide the proper amount of protection between the two surfaces. The result is less waste with better protection.

A final option is to groove the lifter bores. This can be done with a lifter bore grooving tool, which is relatively simple to use. The tool cuts a vertical groove into the lifter bore. Some of the oil exiting the lifter oil gallery enters this groove and is directed to the face of the cam lobe. This method works but isn't as efficient as using lifters with oiling holes. Be aware, however, that if you use either method (both in one engine aren't necessary), you may need to reduce the amount of oil restriction in the galleries.

Once you have your engine built-or when you pick up your new engine from your engine builder-you must take a few special precautions the first time you crank the engine. Properly breaking in an engine requires running it without a load (if the engine is in a car, the car should be in neutral) for 45 minutes to one hour. During this time, the engine should run around 2,000 rpm, occasionally varying the rpm between 1,500 and 2,500. However, the engine shouldn't be allowed to idle because the oil pump isn't spinning fast enough to provide enough oil pressure at those low rpm levels.

Before cranking the engine for the first time, it may also be necessary to make a few modifications. Since the engine will be operating during the break-in procedure at low rpm levels and won't be under load, it isn't necessary to have the full valvespring pressure. Consider swapping your valvesprings for a set of break-in springs, which have reduced pressure and won't be as hard on the cam. Often, if you are running a pair of nested springs, you can run the outer spring by itself. Just make sure it has between 100 and 120 pounds of pressure on the seat (but never less than 80) and around 280 pounds over the nose (but never more than 300). Running your regular high-pressure valvesprings during break-in is an easy way to "wipe" the lobes. "Wiping" is an engine builder's term for when the cam is destroyed as a result of scrubbing off the crown on the lobes that help the lifters spin and provide proper oiling. The pressure between the cam and the face of the lifter simply grinds off the nose of the cam lobe.

Finally, don't forget to spin the oil pump to bring the oiling system up to pressure. You can do this with a drill, spinning a special tool designed to engage the oil pump driveshaft. Often, racers make the mistake of only spinning the oil pump until they see movement at the oil pressure gauge. This is a mistake because the gauge fitting usually attaches somewhere along the main oil gallery. You may have pressure there but not anywhere along the valvetrain from the lifters to the rocker arms. A better idea is to pull the valve covers and spin the oil pump until you see oil coming out of every rocker arm. If you can't do that, then continue spinning the oil pump for five minutes after you first see movement at the oil pressure gauge.

When you finally crank the engine, make sure that you are absolutely ready. Overusing the starter and repeatedly spinning the engine without it firing is very damaging to a new engine because the starter doesn't provide enough revolutions per minute for the oil pump to work effectively. So take a minute to make sure the distributor is properly installed, all the plug wires are on tight, and the carburetor linkage is set up properly. Once the engine fires, proceed directly into your break-in program while keeping a close eye on your oil pressure gauge. It may be 45 minutes of pure boredom, but the results should mean a season of trouble-free performance from your valuable race engine.