Cam Break-In Basics In terms of cam break-in we've learned some twists on an old story. In the old days, the drill began with coating the camshaft with that black moly grease. Today you'll notice that most camshaft manufacturers are using a more viscous liquid. The new liquid performs the same job with fewer negative qualities. The next step in the break-in procedure was to preconfigure the engine with proper static timing and fuel in the carburetor, pressure-lube the engine within a couple of hours of startup for best lubrication, and ensure the engine started immediately upon cranking. This is critical because excessive engine cranking wipes the lube off the lobes before the engine starts. Perhaps the most important step in the break-in process is to bring the engine immediately up to a minimum of 2,500 rpm or more. This is vital because most V8 pushrod engine camshafts are not pressure-lubed. Instead, the cam relies on splash oiling brought up from crankshaft movement. A higher engine speed for the first 20 minutes ensures plenty of oil reaches the camshaft. Another tip is to vary the engine speed throughout the initial 20-minute session to ensure that random splash oiling reaches all 16 cam lobes. Of course, it almost goes without saying that the engine temperature and oil pressure are within specs during this crucial break-in time. All of the above has been covered in detail in stories that date back over three decades and has probably achieved near rite-of-passage status among car crafters. While most enthusiasts are aware of the significant changes in oil, what has received much less attention is the importance of using moderate spring pressures to ensure proper life span. For example, we used a set of typical Z28-style valvesprings in our most recent small-block. They measured 130 pounds on the seat, and that may have contributed to killing the camshaft. During our postmortem investigation, many engine builders said this seat pressure, combined with the open pressures of around 350 pounds, might have been borderline excessive for break-in. These same engine builders now avoid seat pressures above 100 pounds and prefer springs of around 80 pounds on the seat. This reduces the load on the lifter and enhances the potential that the cam will survive. Another engine builder suggested that if the flat-tappet lobes are centered in the lifter bores it can contribute to reducing lifter spin, which will also kill lifters. The new prep lube used on modern camshafts is an engine assembly lube such as this Comp Cams–supplied material. This oil is less abrasive than black moly lube. A light coating on the lobe and lifter face is intended to supply lube only for the first few seconds after startup. The new prep lube used on modern camshafts is an engine assembly lube such as this Comp Ca Pressure-lubing a new engine and camshaft is an essential step to ensure the lubrication system is fully primed before startup. This includes lubing until oil appears at the top of the valvetrain for all 16 valves. This may require turning the engine over a couple of times while pressure lubing. Pressure-lubing a new engine and camshaft is an essential step to ensure the lubrication s To ensure that hydraulic flat-tappet camshaft survives the break-in procedure, it’s best to use low seat pressure springs. If you’re not sure about the spring pressure your heads are equipped with, they can be quickly measured with a drag racer’s spring pressure checking tool like this digital unit from Proform. This spring indicates a mere 55 pounds of force to open on this stock spring. To ensure that hydraulic flat-tappet camshaft survives the break-in procedure, it’s best t Removing the inner spring from dual spring applications will also make life easier on flat-tappet camshafts. This is especially true with big-block engines like the Rat motor, which compounds the problem with angled pushrods that tend to side-load the lifter and reduce the chance that it will rotate in the lifter bore. Removing the inner spring from dual spring applications will also make life easier on flat In the quest for more durable flat-tappet camshafts, Comp now offers Pro Plasma hardening for any flat-tappet camshaft in the Comp catalog. This is a nitriding process that combines case hardening and added lubricity applied to the entire camshaft to minimize wear in the initial break-in process. This adds $105 to the cost of the cam, but it’s also cheap insurance. In the quest for more durable flat-tappet camshafts, Comp now offers Pro Plasma hardening « | 1 | 2 | 3 | 4 | » | View Full Article By Jeff Smith Enjoyed this Post? Subscribe to our RSS Feed, or use your favorite social media to recommend us to friends and colleagues!