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Ya know, you just never know if a complete cam failure was something you did or something the manufacturer did.
If everything went, one could suppose that the cam was improperly treated by the manufacturer, or you did something to take it out like over rev'd the engine, installed used lifters, didn't break it in properly. The latter "didn't break it in properly" covers a wide range from improper or inadaquate break in lube, too slow of an idle during the break in period, or too fast.
Something unrelated failed and the wreckage thrown around or circulated with the oil took the cam and lifters out.
The springs could apply too much open pressure for a street driven engine. For instance, if you used high pressure springs intended for this cam in a racing situation, then drove it on the street mostly at low RPMs (compared to racing) the dynamic load on the lifter/lobe interface increases as a function of the elapsed time it takes for the lifter to climb over the lobe this wipes the lubrication off the cam and presto wiped out parts.
Oiling can be an issue with lower engine RPMs comes less oil being splashed around inside the engine. If you modified the oil returns so that the valley only drains from the front or rear, the cam is greatly deprived of lubrication, especially when combined with low RPMs and high spring loadings.
Another problem is running the SBC with a hot cam, high spring pressure and no cam button. The cam really walks back and forth under this condition and can eat lifters and lobes in no time, often getting the distributor gear as well. Also the lifter bores could have too much clearance, this allows the lifter to wobble which digs its edges into the lobes. A similar event can occur if there's too much clearance in the cam bearings allowing the cam to orbit in its bearings.
Then there's the issue again related to lots of spring pressure and low rev operation where the loading and unloading of the individual lobes snaps the cam back and forth as it rotates. This can excite a lot of weird frequencies in the cam and you can then impose another excitiation from the crank through the timing gears and or chain, which can really put some odd twisting moments or the cam. Take a real careful look at the timing gears and chain for odd or excessive wear given the mileage on them. These frequencies can cause the cam to attempt to rotate somewhere other than on its longitudinal center, this will also hammer the lobes and lifters.
So you can see there's a lot of things that can go wrong from what the manufacturer did or didn't do, to what you've done or not. Not to mention the effects of freaky frequencies that parts can develop.
Bogie
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