Cu/Be is mostly used as seat material where Ti valves are employed. Colsibro is also a proprietary widely used alloy for racing valve seats with excellent heat conductivity and durability.
Hollow cams are actually much cheaper to make than solid ones. These cams, found in many cars today, are fabricated using the hydroforming method, where the lobe rings are prepositioned in a precision jig around a steel tube. Then, a very high pressure burst of water is applied inside the tube, deforming it enough to securely jam the lobes in place. However, there have been many instances where the lobes dislodge and rotate on the shaft!
Hydroforming has been used for years to make auto chassis frame sections in many auto plants; I believe it was first used in the US for pickup truck square section members. Note we're talking several thousand psi here.
Hollow crank rod journals are very common in some Formula racing classes. The entire journal is hollow and the outside ends are sealed with a suitable length of aluminum tube pressed in place. The internal space between the tube and the journal allows oil circulation for proper lubrication. Weight savings are understandably considerable but machining is very expensive!
Jim K.
Well guy, you'd better think about how exactly you're going to do that!! I was looking at a 2liter crank the other day and I figured special tools and jigs would be needed to do this. Is it really worth it though? In F3 it pays off as they have really small flywheels+clutch packs and very low vehicle weight. How much do you expect to gain? You can lighten the pi$$ out of the crank counterweights and flywheel and achieve a lot, isn't that enough? Besides, I think this technique is used mostly on billet cranks.
Jim K.
Jim K.
Aaaahhh....
you should have seen me grinning here. I actually thought about it for a fraction of a second (lots of years ago).
Of course it is not worth it. My rear FW still weighs 1.8 kg and the new front one will be about 3 kg. Crank should be around 15 kg when lightened. That will be enough for me.
you should have seen me grinning here. I actually thought about it for a fraction of a second (lots of years ago).
Of course it is not worth it. My rear FW still weighs 1.8 kg and the new front one will be about 3 kg. Crank should be around 15 kg when lightened. That will be enough for me.
