View Single Post
Old 10-10-2008, 04:11 AM   #17
Jake Raby
Engine Surgeon
 
Join Date: Aug 2008
Location: Cleveland GA USA
Posts: 2,425
One thing my CN controlled balance machine has taught me is that rotating masses must be balanced as units.. I can hang a perfectly dynamic balance flywheel onto a rotating mass assembly and to correct the "plane" 2-3 grams of material will have to be removed from that flywheel to bring the entire mass in an .5 ounces per inch or below. Stabbing an new part onto an assembled engine is never optimum as you can't correct the plane differences as the engine is assembled. Reducing the component weight further impacts the balance differential that the mass will see with a component swap with the rest of the engine assembled.

We even balance index pressure plate bolts and washers.. @ 6"+ radius everything is critical..

I have seen 3 Boxster engines with loose crank pulleys so far, one did fall off...

The sprung center disc is a great addition to the driver and tranny, but does very little to absorb the harmonics within the engine. I am working on a harmonic balancing crank pulley that could be added to the engines that have lightened flywheels for some dampening, something set up like a Chevy is the current prototype.
Jake Raby is offline   Reply With Quote