Right or wrong, I always use .009 at the valve for the IC for Wallace’s dynamic compression calculator. The .004 or .006 at the valve might be more accurate if every cam had the same lash ramp design with in the same series and in the OEM world. I simply do not use the ASAE SAE specs much. We try to check specs for cams out at the valve at .009 or check the .006 tappet and add the effect of the rocker arm ratio in. I use cam DR numbers, but also have checked cams and ran regression coefficients to take out the extremes on measurements. Compcams and Bullet I can pretty much use the published profile numbers. I prefer Bullet, you do not get the Corporate answers like the big companies. I haven’t done much with Cranes for a while, so the crane stuff is not as fresh in my mind as it use to be. At one time I had high and low dcr number recommendation for all the crane cams for a 400 cid engine. I wish I had it yet, the trends were interesting as the cams went bigger and switched to rollers.
It is exactly right that the lunati HR will have the similar dcr numbers, it doesn’t account for area under the curve, cam asymmetrical trends, or the E/I split on the head flow and cam. I just trend the DCR down or up on that stuff and adjust the overlap so the exh closing is not behind the intake closing on the overlap for the ICL depending on the E/I duration split.
Usually the asymmetric measurement or the pan is measured from .004 tappet to .050. By .010 tappet most cams are symmetrical. The lobes UD Harold designed seem to run around 8 on the pan. His past comments I have found to be true on his cam design and pan. The cranes hmv series are 5, comp XE if I recall correctly run about 6, magnums have pan to, but I do not recall how much, at least 5. I have never seen a crower having any pan, I have seen a lot of intentional design making the lash ramps gentler.
What does the pan matter? That pan changes the way the cylinders are filled. If your already pushing compression putting a cam in that is really good at filling cylinders is not helpful. You need to adjust the dcr down via the static or a bigger cam profile.
When your doing budget builds and using books cams sometimes have to work with the best match of off the self parts. In this case it looks like the 14cc dishes icons and the 2802 should be good choices.
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