The N21 Paul Burke cam was too much for the rockers. I will follow up with more detail when I learn more
Aluminum bits in the oil.
- Thread starter Stan
- Start date
head ported/polished at all?
Cyl. head shavings would do it.
Cyl. head shavings would do it.
Yikes, lots of his cams out there!
The Burke Cam has a valve steep curve with a longer open valve /—\
This aggressive valve action caused a an eccentric to fail & peen the end of an exhaust valve
Stock Cam has gentle sine wave valve curve~--~
This aggressive valve action caused a an eccentric to fail & peen the end of an exhaust valve
Stock Cam has gentle sine wave valve curve~--~
Love the keyboard graphics!!!
stronger rocker arms recommended.
BMW OEM - more expensive but stronger.
Stan, what failed?
Rocker pads and valves are not aluminum- what am I missing?
Our VAC Aluminum Rocker Arms are here to dispel the myth that heavy steel rockers are needed to maintain reliable performance and sacrifice high RPM stability.
Apparently not...
These are not the brand but Mario L told me that the aluminum bits were from the rocker arm
Well Stan said they were aluminum, not Mario. I don’t have to tell you, but steel shavings bathed in oil look a lot like aluminum.
My personal experience with aluminum shavings is that it turns your oil into aluminum purée.
Like this. Although my gearbox was the color of anti-seize.
Glad I have stock rocker arms and the N21 cam is a street cam and not that aggressive.
Yes, the stock rocker arms are better. I too have the N21
Surely the super light Alu rockers also have steel pads?
yes but when the nut came loose and started bouncing around, I think that is where the damage occurred.
I hate that this happened. But if I am understanding it correctly, I like the "cause" being the nuts loosening rather than a metal on metal erosion of surfaces that were otherwise intended to ride on one another.