Are they using the RO7 engines or the older SB2's? The flat-tappet cams they must use are unusal in that they are steel and have no rake angle. The cam and lifters are flooded with
oil in the sealed cam tunnel to ensure adequate oiling. The valve train is always pushed to the limit. I'm surprised the problem didn't show up during Spintron testing. Problem is, as best they try, you can't always simulate actual track conditions. Back to old, but proven hardware.