Hi Lift Camshafts And Base Circles And Lifters..

[rob82]

Out of curiosity, is the the duration or lift that gives the car a lumpy idle?

A lumpy idle has more to do with the seat duration, ie the duration just as the valve opens to when it seats. Depending on the camshaft profile and the runout will also affect idle. I'm reserching some cams that are in the order of 264 at 4thou lift duration but 230 at 50 thou. This profile is very aggressive, probably too aggressive for a high reving 26 but not a rb30/26.

13mm Shims are massive I would definately not be using a shim that large. Another approach with grinding of the base circle would be to tip the valves that way you can use standard size shims around 2-3mm and standard buckets. Might need better springs thou.