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What is ZETEC?

ZETEC is the name of the motor, similar to Chevy's ECOTEC, and Honda's B16, H22 series motor names. The ZETEC engine features something similar to VTEC called VCT. See 'What is VCT' for more info about it.


What is the difference between the ZX2 ZETEC and the ZX3 Zetec?
While both motors share the ZETEC name and appear similar to the untrained eye, they are different. Both bottoms end are the same, while the heads of both motors are different. The ZX2 posses VCT on the exhaust side, while the ZX3 (with the exception of the SVT focus) do not have VCT. The SVT focus has VCT on the intake cam. Transmition are also different. The ZX2 MTX uses a G5M tranny, while the ZX3 MTX uses a MTX-75. The bolt pattern for the tranny mounting is almost the same on the ZX2 and the ZX2. But there is one bottom bolt that does not line up. You will have to modify the frame rail, and get some new axles (contact http://www.zxtuner.com for axles) but the MTX-75 is a possible swap.


What is VCT??

VCT stands for Variable Cam Timing. It is controlled by oil pressure, basically to control valve overlap and help control emissions and help out with gas mileage. With VCT off (at idle for example) the exhaust cam is fully advanced, with minimum overlap. As VCT becomes active at some rpms the cams are partly retarded (with more cam overlap) increasing upper rpm power. Under some conditions the cams are fully retarded 60 (cam) degrees resulting in EGR like behavior. At 60 degrees, the cams are retarded too much to make optimum power. If you eliminate the VCT you need to adjust the cams on a dyno for the best retardation to optimize power. This best peak HP setting will result in more static overlap than with the VCT active and net less low end torque. Nevertheless if you are after peak HP, eliminating the VCT is a good way to do.
Ford uses the VCT to retard the exhaust cam as much as 60 (crank) degrees. This results in a lot of overlap and some exhaust gas recirculation. Most of the time the amount of cam retard is too great to benefit high end power.


What is the difference between the ZX2 VCT and the ZX3 Zetec?

ZX2 has the VCT on the exhaust side. The ZX3 except for the SVT focus doesn not have it. The SVT has it on the Intake side.

One side effect of VCT is that the ZX2 uses more aggressive cams than the ZX3 and still meets emissions requirements.

ZX2 Intake: 214 deg @ 0.050, 0.366" lift
ZX3 Intake: 206 deg @ 0.050, 0.353" lift

ZX2 exhaust: 211 deg @ 0.050, 0.338" lift
ZX3 exhaust: 205 deg @ 0.050, 0.342" lift

If you need to meet emissions testing, the VCT engine will allow you to run more aggressive cams. If you don't need to meet emissions testing, then the VCT has little value.


What other cars have VCT??

99 and '00 Zetecs in Contour and Mystique models have exhaust VCT.

All Zetecs in ZX2 and Cougars have exhaust VCT.

No other Zetec engines (Focus, Escape, pre-'99 Contour) have exhaust VCT.

SVT Focus has intake VCT....

That should just about cover all the North America Ford and Mercury cars with Zetecs...


When was the first ZETEC??

"The first Zetec dates back to 1992, when it first appeared in Escorts (1.6 and 1.8 and Fiestas (1.. The 16v head was developed by Yamaha and based on a strengthened CVH block. The Mondeo was the only vehicle to use the 2.0L derivative of the engine, which appeared in 1993. The early engine is identified by looking on the cam cover - on the front left hand side it will read 'DOHC 16V' "

More info:
http://www.fiestaprojects.com/zetec.html