I see the engine is a 3-valve chain-driven SOHC with variable valve timing, but I'm curious about the 3V setup. Is it 2 intake & 1 exhaust? If so, do both intake valves work full-time, or is it 1&1 up to some cut-over RPM when the other intake opens? And, what are the valve sizes? Is the variable valve timing continuously variable? Does the torque curve show any discontinuities caused by non-linear valve control?
Inquiring minds want to be fed.
The new heads use 2 intake 1 exhaust. Ford calls the new valve timing system Dual Equal Variable Cam Timing. It is a hydraulically actuated system that simply changes the phasing of the SOHC shaft to the crank. 50 degrees of total variation. There is no control of individual valves. The Ford literature I have says it controls timing in varying amounts in the midrange and WOT. Timing is retarded at WOT. Its suppose to be the same system as on 5.4 Triton. As a matter of fact, I believe the two heads (Triton & Mustang) are very similar to each other. This ability to control cam phasing is also used for emission purposes. Apparently it has allowed Ford to skip EGR and air injection on this engine. If I remember correctly, on the 2.0 Zetec engine a few years ago, which had variable cam phasing of the exhaust cam, the EGR was deleted. Deletion of EGR system on that engine basically paid for the VCT hardware. Although individual valve control is not used, ala VTEC etc, the heads now incorporate (some lit has said these valves are in a spacer between the intake and head) something called charge motion control valves that try to simulate two different sized intake ports. I'd like to see more detail on these, or photos. It sounds like another version of the intake control on the 96-98 Cobra, but maybe not. About valve control, don't know if thats continuous or discrete steps. Even if it was stepped there would so many ways, especially with the engine now having throttle by wire, to mask the changes I'd guess you could get a pretty smooth torque curve. Probably no surge like that felt on a 96-98 Cobra when the intake control valves open at around 3,300 RPM.
Sounds like good engineering: higher HP/TQ, higher MPG, and lower cost. Now, as soon as my wife trusts me with the checkbook, ...
And, I forgot to say -- thanks for taking the time to inform me.
Sure thing Bob. Given the amount of time Ford is spending talking about how the new 3 valve head has the performance advantages of 4V DOHC heads without the added cost and complexity, it will be interesting to see what the 2007 Cobra contains.
Any idea what Ford will put in the '06 Mach 1?
The 2003 Cobra engine? 390 hp? 390 ft-lbs of torque? :-)
Not unless they start making that motor again. I heard it's done.
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