If your engine misfire turned into a broken cam or flashing check engine light, you may be wondering what went wrong. Camshafts, especially in high performance applications with roller tappet cams or flat tappet cams, rely on stable mounting and exact torque. At Behind The 8, we understand your vehicle’s a precise piece of machinery, so when camshaft bolts fail, it’s not a laughing matter, and can increase crash potential. We’re here to help you understand why camshaft bolts break: common causes and fixes, so that your engine is protected and you can avoid costly repairs.
The Torque Trap
One of the most common places for error is improper torque settings. When cam bolts are over- or under-torqued, they reduce clamping force, which allows movement during the rotation process. That movement doesn’t just affect the cam lobe surface—it alters timing and can distort the cam’s profile. Over time, it may cause forward and backward movement that stresses the thrust plate, wears on the cam bearings, and can shear dowel pins. Always torque to factory spec using a calibrated wrench, a priming tool, and the correct hardened washer. Missing those steps invites trouble. Improper torque can lead to engine oil starvation, oil filter leaks, cracked valve guides, or even a connecting rod contacting the camshaft, especially in engines with tight tolerances.
Cheap Hardware, Big Problems
Bolt quality plays a bigger role than most people realize. At Behind The 8, we don’t compromise here. Using incorrect bolts or reusing stretched torque-to-yield fasteners isn’t just a risk—it’s a failure waiting to happen. Subpar bolts can fail under spring pressure, damaging the valve train, pitting the lifter face, or forcing exhaust valves to open early. That’s how you get piston contact or blow a head gasket. Anytime you’re installing a new camshaft or working on the cylinder head, replace the cam bolts with high-quality, application-correct hardware.
Shaken, Not Secured
Harmonic distortion in the camshaft doesn’t just show up overnight. It creeps in, usually near the timing gears or loosened timing gear bolts. Without a harmonic balancer or proper thread locker, vibration will undo even a clean install. Don’t underestimate this. Lubricate every moving part as specified, and confirm oil splash is hitting every lobe and bearing surface. Flat tappet cams require engine oil flow and protective film to stay alive, especially at startup. Use the correct break in lubricant, stick to a proper break-in schedule, and confirm ignition timing. These small steps protect camshaft lobes, lifters, and reduce the chance of symptoms like power loss, misfires, or when a rocker arm swings farther than it should due to geometry issues.
Alignment Chaos: Misfit Parts That Break Everything
When cam housings are warped or cylinder heads are out of true, everything else suffers. Misalignment causes contact between parts that were never meant to touch. That’s when you start seeing erratic valve lift, premature wear, and spring coil bind. A misaligned system won’t just reduce valve clearance—it can increase friction, damage the cam cover, affect fuel system timing, or even burn out the drive on a fuel pump. Anytime you’re reassembling a top end, check for flatness and confirm assembled height is within spec. That’s how you avoid a chain reaction of part failures.
Thread Trouble
Thread prep may seem minor, but it’s where a lot of builds go wrong. Dirty or contaminated threads alter torque readings and undermine bolt performance. That’s a fast track to a broken camshaft or compromised alignment. Clean threads thoroughly, apply thread locker where called for, and never tighten cam bolts or head hardware with an electric drill. If you’ve seen cam lobe scoring, broken dowel pins, or signs of failure on tappet cams, it’s time to start from the crankshaft and trace the issue forward.
The Right Components For The Job – Behind The 8
When diagnosing camshaft bolt failure, remember that many factors contribute: lubrication, maintenance, valve spring condition, and installation habits all play a role. With so many key failing possibilities, it’s important that your purchases be protected. Behind The 8 offers high quality cam shafts, expert advice, and a warranty policy that gives you confidence in every build! For a quote on replacement components that prioritize your engine’s function, contact us today.
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