and duration is followed by raising the lift. It's quiet impossible to have longer duration without getting higher lift.

Mad pretty much summarized everything, so I have nothing else to add, but say that you shoudl stay away from those cams.

 

It is possible to make good regrind cams for the beta. Supertech sells some crower regrind cams... wink1.gif

 

No, that doesn't increase duration...unless you're making a joke about the valves being open through 360 degrees (yeah, that's an increase in duration all-right).

Assuming your shims are to spec, adding a thicker shim would keep the valves slightly OPEN all the time once the engine heated up, not good. You're not going to get any measurable duration out of removing the .02" slop in the valvetrain. Those parts heat up, as they heat up they expand, and the slop dissapears to unmeasureable levels. Get a good micrometer. Measure any shim thickness at room temp, then drop it in boiling water for 5 minutes (roughly 212 degrees), and measure the shim thickness again. Do the same with the cam lobes. That's why that clearance is there as a factory spec.

I've seen guys try the same "trick" on motorcycles, and end up with valves that stay open once the engine gets hot. Not to mention added parasitic drag from the constant wear on the cam lobes and shim. Eventually, the lobes and shim wear down, and you end up with less duration, and less lift. At that point, even installing proper spec shims won't get you back to stock specs as the cam lobes themsevles are worn down. Now you need new cams, and new shims.

Regarding your specific questions. Avoid "mystery" cams like you would "mystery" meet in a resturant.

 

Random, when I mentioned thicker shims.. that was for the regrind cam. you need to make up for the material removed from the cam.. and thicker shims are one of the ways. I would never recommend running just thicker shims without them being needed.

 

Yeah sure, but those are regrind from Crower blanks that are bigger at the start than our OEM cams. tongue.gif

 

Mad-Machine
Well said. Sorry I doubted ya! fing02.gif