Think of the camshaft as the mechanical backbone of the valvetrain. It controls the precise timing of valve operation, which dictates when intake and exhaust valves open and close, managing airflow, and keeping combustion cycles in check.
When it’s working properly, everything runs in rhythm. But when timing is off or components aren’t in sync, that backbone can (literally) crack. Camshaft failures are rarely about poor casting or weak materials. More often, it comes down to improper installation, lack of lubrication, or using components that weren’t meant to work together.
At Behind The 8, we specialize in diesel cam shafts and other heavy-duty engine components, so we know a thing or two about how and why camshafts break. Let’s take a closer look:
Catch the Warning Signs
Your engine will let you know when something’s off. Ticking from the top end, rough idle, misfires, torque loss, or a check engine light can all signal issues related to your camshaft.
Don’t ignore erratic ignition, low-speed surging, or changes in how your fuel system responds. In many cases, what looks like a sensor problem turns out to be mechanical—like a broken camshaft, deteriorated cam lobe surface, or wear at the cam bearings.
If the rocker arm swings farther than intended or if there’s forward and backward movement in the valvetrain, it’s time to take a closer look. Spotting problems early could spare you the cost of a new camshaft or damage to the cylinder head.
Lubrication is Everything
Flat tappet cams require engine oil to do more than just reduce friction—they rely on consistent oil splash to maintain a protective film between the cam lobe and lifter face. If oil passages are blocked, if the oil filter is clogged, or if the pump can’t maintain pressure, that protection vanishes fast.
Once the cam lobe surface starts to score, it’s only a matter of time before the tappet cams wear through. The critical moment is during startup and break-in. Without the correct break in lubricant, those lobes won’t seat right—and a broken camshaft won’t be far behind.
Don’t gamble with a dry start or dirty system. Change the filter, check the pump, and give the engine what it’s hungry for.
Valvetrain Setup Mistakes
Incorrect valve spring pressure is one of the fastest ways to kill a cam. So is ignoring spring coil bind, improper assembled height, or failing to verify geometry.
When the rocker arm swings farther than designed or the springs increase valve lift beyond the lobe’s profile, stress builds fast. That’s how you end up with damaged camshaft lobes or stress fractures in the cylinder head. Add in misaligned connecting rods, off-center pushrods, or cheap cam bolts, and you’ve got the perfect mix for failure.
Always verify end play, use the correct hardened washer, and follow your cam manufacturer’s height specs. Skip any one of those and you’re asking for trouble.
Timing and Harmonics: The Silent Killers
When timing components break—be it the chain, gear, or tensioner—the rotation process breaks with it.
Loose timing gear bolts or worn dampers allow vibrations to travel through the system unchecked. If your engine’s timing feels unstable or performance is degrading without an obvious cause, it could be more than just wear—it could be vibration from the crank or a failing balance system that’s eating your cam alive.
Smarter Installs Start Here
At Behind The 8, we offer precision-crafted dohc camshaft injector systems and cam shafts for every type of install. Whether you’re installing a new cam or correcting damage from shipping or improper handling, our components are engineered to withstand high-performance demands. Contact us today for a quote and protect your camshaft investment!
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