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About the rockers: I realise the rocker action is not 1:1 either, and by altering the rockers pivot point (the rocker shaft) lower or higher, you also alter this. But this effect is not near a large as the lifter-lobe mushroom effect.
About my example D: you say With a flat lifter the acceleration of the valve is faster coming off the base and slower approaching the peak of the lobe, as your curves show. This is GOOD But that is basically what I tried to do. I think that the actual valve action on Case D, is pretty simular to Case A (stock). But in Case D, I'd say, there is less wear then the stock situation, since you INcrease the metal-to-metal contact. You say little metal-to-metal contact results in little wear. How can that be true? The large contact area, the lower the froce per area, so little metal-to-metal would actually create MORE wear imo. Which is why large main / bigend bearings last longer then small bearings. Right?
About the fact there is no optimum cam, and everything has to match: I know. I just like to know more about this subject. IMO, the design of the lifter-cam lobe interaction is pretty crappy. It works ok, but not without relative much wear. (se the pic I just posted as a reply to B20Paul) A wider base on the lifter would be nice, since this wear pattern shown in the pic would be gone, but there is no room for such an alteration. Roller lifters would be ideal, but would require quite a bit of alterations to the block.
I'm just pondering about all this, and hope to learn more with the help of you guys. So like I said earlier: keep those replys coming!
Cheers, Ben
ps. Basically I was just thinking how a cam and matching lifter would look like with:
-stock duration
-stock lift
-more area under the curve
-less cam/lifter wear
-relative low peak accelerations
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P131, '65, B20B+M47. P131, '69, B20E+AW71L+LSD. (www.tinustechniek.tk)
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