Sonreir said:
I don't believe that's what led to the failure. That was several months prior to the problem. And it was more like 3/4 throttle.
Does that mean that you had done of few runs prior to that where you had maintained rpms above 6000?
Since the oil does cool the engine, and the faster an engine goes, the more friction is generated, thereby increasing its cooling requirements, its likely that had you sustained rpm of maybe 4000 instead of 7000 with your oil level, that the amount of oil you had would have been sufficient enough to keep the engine cool enough to prevent the failure.
In cases like this where there is no question that increasing the amount of oil to the top end will definitely help reduce the potential for failures, there is more than one way to reduce them . . In other words, if one does not increase the amount of oil to the top end, they can try other methods, and the simplest one is to use better oil . . If one is already using the best oil on the planet and failures are still experienced, cooling the oil would be an additional option . . If doing both of these don't work, one could try a thinner oil . . This would perform a similar function to modifying the system to increase the quantity of oil to the top end, HOWEVER, if the oil is the same brand that was being used, it will have LESS protective qualities, which means that increasing flow AND using a thinner oil is not necessarily the best option, but increasing flow and using the same viscosity and brand will help.
My point is that there is no substitute for high quality oil . . The weakest link in any chain will be the first one to break, and you can have a gallon of oil per minute flooding the top end, but if the oil is not good enough for the app, there will still be failures.
I understand people not knowing which oils are better than others, but I don't understand the people that know which ones are better yet still buy the lower priced ones for an expensive machine or even for any machine for that matter . . I'm not suggesting that this is what you did, I am only mentioning it as a general thought.
imo, it's a bit like people that buy Chinese parts for their car and then cry when they break . . Well, either quit your $5.00 job at Mcdonalds and get better one so you can afford better parts. or if you have enough money and buy Chinese parts and they break...don't cry and look for sympathy when they do.
As far as the reason that a rocker arm will fail before a cam lobe does is simple . . The amount of force applied to both is exactly equal and is applied to the same amount of area at the point of contact, however, because the cam rotates and the rocker does not, the area on the cam keeps moving so the pressure is not applied to the same spot for nearly as long.
It would be similar to dragging the rocker along the road as you drive . . You can see that the rocker and road receive the same amount of force but the road is no longer in the same spot as it was when you started but the rocker is still in your hand . . This is basically the premise upon which the Timken wear test operates, which is the same premise that all grinding wheels operate, but in this instance, an abrasive is added to the wheel to speed up the "wear" process.
Once the rocker face is worn, it will more easily damage the cam lobe and the rate of cam wear will increase . . Another way to reduce rocker wear is to have them hard welded, however, this is still not a substitute for high quality oil or increasing the amount of oil to the top end and really is only necessary for high perf apps.