After having a few cam followers come apart and drop needle bearings through the oil pumps on a previous engine, discovery of the real reason behind the chain of events has led to the opening of another can of technical crap-worms in the 6.0 racing world.

As some may know, the rear timing gears of the 6.0 are helical cut-meaning they are cut at an angle. Any helical gear generates a certain amount of thrust load at a given speed and torque level. In the case of the 6.0, this thrust load pulls rearward on the camshaft, and forces the crankshaft and the pump shaft of the HPOP forward. Increasing engine speed and/or output torque (both are a factor in these applications) will amplify these forces. While traditionally this is not an issue, this engine has seen upwards of 5500 RPM and 1000+ pound-feet of torque.

Interestingly enough, the force of this was actually enough to PULL the pressed-on gear of the camshaft part of the way off the rear of the cam, all the way up to the flange on the rear crank. This caused the camshaft to have endplay- a significant amount of endplay ( a measured .128 inches, over an 1/8th of an inch) and the walking back and forth twisted on the lifters, causing them to fail.

You can see in the pictures the amount of camshaft movement. I don't know how long the lifters were exposed to this over-tolerance (I'm sure it grew as time went on) but it did cause catastrophic failure.

There are two potential solutions to this problem- one being to TIG-weld the cam gear onto the shaft, and two to engineer and install straight-cut gears for the rear. I don't particularly care for solution one because as I see it, it is a band-aid for the real problem. Solution two is an issue because the crankshaft is a two-peice crank, with the rear of the two containing the gear. This rear peice cannot be removed without throwing the crank out of balance and the rear main seal surface out of round, so the new peice would have to be installed on the crankshaft before machining, then the entire assembly would have to be rebalanced after the final cuts were complete- which will get very expensive very quick.

Any of our resident techs or engineers have any thoughts on the subject?