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...a control cam was introduced, ground and cam doctored by MI in Melbourne. These engines spin to over 7000RPM with a single (mandated) valve spring, which is a big compromise compared to using dual springs.
Not long after, most nearly everyone started to have lifter failures, regardless of oil used. If there was a slight mis match between lifter radius and lobe taper, lifters wouldn't rotate, or not rotate adequately resulting in immediate failure, particularly if not run in adequately. We actually built a cam run in rig so that we could ensure this was all ok before firing up a newly built engine and then running in the cam. We also rejected lots of lifters (insufficient radius) before installation. We also never had a cam related failure ever using oils ranging from Neo 0W-5 (which is what I ran) through Castrol SLX to BP Visco 5000. Prior to this BP Corse 30 was the gun oil, but HP, torque, engine wear and ability to handle higher oil temps was better with the synthetics. Corse 30 fell over dramatically at around 105-110*C, which is easy to acheve, so keeping it cool was an issue. The only changes when running the synthetics, particularly with the 0W-5 was finer bore finishes, plateu honing and dramatically tighten up of bearing clearances, all of which are pretty basic when using a lighter oil.