Cams Part II

So, what am I running?

If you have read my previous posts, you'll know I'm starting my first build in a while - with a heavy  leaning towards being streetable.

I have a cam left over from the engine I was planning to build before I married - a Web-Cam 111.This gives 238 degrees at 50thou' and 476thou' (12.1mm) lift with an "advertised duration" of 272degrees - i.e. what would be termed an  aggressive high lift short duration cam.  The rate of lift is pretty high, but in reality .476" is not that high as a stock VW head can tolerate at least .5" of lift.

I know experts will tell me this is not enough duration for an engine of this size but  the  truth is duration is only part of the equation and should actually be related to the speed of flow through the heads, not the size of the engine.

While it is tempting to use longer duration to compensate for the reduced port speed of smaller intakes, if the flow is high enough it should not be necessary.


Higher lift, while accelerating the valve more (and increasing the danger of float,) helps to increase flow in any good head, and increases the area under the curve - i.e. the time when the ports are actually producing meaningful flow.

Aircooled.net say "it's pretty harsh on the valvetrain,don't expect it to last 50k miles" - but who does on a performance engine?  For all the respect I have for the late Gene Berg, engines with high lift (i.e. those that perform as we'd like) tend to need a head job by 50k - funnily enough, about the point that VW mechanics here said they would...