Cam and valvetrain longevity....??? low duration high lift...
#532
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Doesn't have anything to do with Bob. 90% of the stuff I've been messing with was all Comp cams. But lobes very similar to what Tim is running. Short duration higher lift. We run most of these engines with short travel lifters. What we have found is stuff moves in aluminum heads. After some run time and a new valve job it settles down and your good to go for awhile.
#535
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I think when we started getting really good springs around 10 years ago, lobe design got a lot more daring and then confidence grew when durable lifters started appearing on the scene. The idea that too much cam intensity was being played down by some pretty smart people because it was working fine in certain applications. Good builders are now on high alert that something that may be very stable at 6k rpms can be very unstable at 3k! These characteristics don't translate well to the marine duty cycle. To my way of thinking, these improved springs and lifters have only now become compatible with the "conservative" and venerable Crane HR's in marine applications. If you are old enough to remember, then you will recall these same and now conservative Crane HR lobes breaking springs and tearing up lifters in marine applications. Now, because of better springs and lifters, the Crane HR's are the gold standard for reliable marine power. IMO they are about as intense while remaining quiet and reliable as most of us need to go. Now, after spewing all of this, I am close to finishing up a motor with Harold Brookshire's last design HR's. LOL
#536
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Harold Berkshire latest greatest design HR =Lunati ?? question not tryin to be smart
#537
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The other thing that seems so common now a days are aluminum heads? Does that potentially add to stability problems and aid in driving the valve seats til they find their happy place? Especially when we continue to take advantage agressive grinds to achieve maximum hp at or under 6k. I know it seems ancient to deal with a set of iron heads but maybe should be looked at more often especially for individuals who prefer less maintenance. Part of the solution could be bigger CI builds with less agressive grinds and some decent iron heads and a little less compression. Just an option....
#540
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Not sure if the VooDoo series is a lesser lift version of his last design or not. The VooDoos are definitely his though. Mine have a little more lift. I just want to try this latest version because I loved an old Ultradyne HR cam I had in a boat years ago. The last designs are claimed to be more stable with more intensity (more lift vs. gross duration) if that's possible. If it ends up being not real quiet on the dyno though, I'll pull the cam and use something from Crane.