MX6.com - View Single Post - Maximum lift of custom cams on stock valves/retainers.

**fredio54** · 7-1-05, 15:59

stock lift is more like what dutch said 8.855 or so, not 9.17, but thats splitting hairs... what eric says sounds plausible in terms of using the stock cams. eric : did you mean starting with 3n or 5a? surely the 5deg difference or something vaguely proportional will still exist afterwards?

given the rate of decreasing returns of flow when adding lift, there isnt a huge amount to be had by going larger without bigger valves. you pretty much never want to exceed 1/3 of the diameter of the valve head anyway.

moral of the story, it doesnt take much extra lift to make good NA power, but it probably will take custom made cams rather than regrinds.

kiwi626 : what specs did your perf guy say the cams in the NA motor he built were?

fred.

7-1-05, 15:59	#4 (permalink)
fredio54 Join Date: Aug 2004 Location: Auckland, New Zealand iTrader: (1)	stock lift is more like what dutch said 8.855 or so, not 9.17, but thats splitting hairs... what eric says sounds plausible in terms of using the stock cams. eric : did you mean starting with 3n or 5a? surely the 5deg difference or something vaguely proportional will still exist afterwards? given the rate of decreasing returns of flow when adding lift, there isnt a huge amount to be had by going larger without bigger valves. you pretty much never want to exceed 1/3 of the diameter of the valve head anyway. moral of the story, it doesnt take much extra lift to make good NA power, but it probably will take custom made cams rather than regrinds. kiwi626 : what specs did your perf guy say the cams in the NA motor he built were? fred.