Many thanks to Paul Baker for writing this guide.
No nothing to do with a certain East Enders character but the acronym used by Ford for their internal anti-theft system. It actually stands for Passive Anti-Theft System and as been around on Fords since the early nineties. There have been a number of generations of PATS ranging from the fairly simple early systems to todays systems that are linked with the Engine Management system. The basic principle of all of the systems is that there is a chip, you?ll notice a litle red tab on a Ford key which is the chip, and I thought it was just to make the key look pretty, that talks to a de-coder which surrounds the ignition switch which in turn talks to the PATS module and on later cars the ECU. When you put the key in the ignition, the signal is checked by the PATS unit to ensure it is compatible and if so the PATS module enables the main circuits to the ECU and to the Fuel Pump thus enabling the car to be started. On later PATS systems these are more sophisiticated and the PATS module also talks to the ECU and enables the fuel circuits in the ECU as opposed to external to it. For the unitiated the PATS system will often be referred to as internal or external dependant if the PATS system is integrated with the ECU or not.
A quick call to a local company quickly confirmed that my Fiesta Si was equipped with external PATS which was good news on two counts, one that I could retain the security and two that I would not need to worry about PATS when changing the ECU, so good news all round really. If any readers want a real laugh try asking anyone in Ford about PATS, you?d think you?d asked for Bin Laden?s phone number the whole area is considered, probably quite rightly, as highly sensitive. If you take the trouble to look at the PATS wiring you?ll quickly notice that all the wires are brown, also for security reasons!!!!!
EDIS can be managed seperately from the ECU via an EDIS module or can be managed within the ECU. All ?93-?97 Mondeos, with the exception of the Automatic, had internal EDIS whilst I beleives that all earlier Zetec Fiestas like XR2i and RS1800 had a seperate EDIS module. Because of this I assumed I would need to do a certain amount of re-wiring to support the Mondeo ECU. However I discovered to my joy that the 1.6Si Fiesta had internal EDIS the same as the Mondeo so in theory I would not need to make any loom changes assuming that the pin connections were the same between the Fiesta ECU and the Mondeo ECU. I set out to try to confirm this but in the process managed to find a contact on the FiestaTurbo.com forum who had done the same 1.6 to 2.0 conversion and had established that the ECUs could just be swapped.
Apart from the engine management considerations there are a number of mechanical changes that need to be done to get the 2.0 Mondeo engine in to a Fiesta or a Quantum H4. specifically these are as follows, for a more detailed description of the modifications required take a look at Mark Stewart?s excellent web site and at Jim Hearne?s equally useful site
The Mondeo sump has the step in the wrong place and would foul the Fiesta Exhaust Manifold, solution is a straight swap for the Fiesta Sump. Whilst you are at it you also need to swap over the oil pick up pipe as well.
Does not line up with the Fiesta Exhaust position, solution is a straight swap. It turns out that the manifold port sizes are the same on the 1.6/1.8 and 2.0 Zetec engines.
The Mondeo water pump is driven by the flat side of the belt and rotates in the opposite direction to the Fiesta so this is also a straight swap for the Fiesta pump and the Fiesat pump pulley
The Mondeo alternator is mounted at the rear of the engine and basically just won?t fit, the solution again is to use the Fiesat alternator and mounting bracket etc
Power Steering Pump
The pump appears to be the same on the Fiesta and Mondeo but is mounted completely differently due to the differences in the drive belt arrangement between the Mondeo and the Fiesta so I used the Fiesta pump and bracketry. You need to use the bracketry anyway because of the alternator swap.
The Mondeo inlet manifold curves back down and basically just won?t fit in the Fiesta engine bay. The solution is to use the Fiesta inlet manifold so it will all fit in. One issue here is that the 1.6 inlet manifold is smaller than the Mondeo one and also the manifold ports are smaller than the 2.0 inlet ports which results in a step change out where the manifold meets the head. Some others who have done this conversion have smoothed out the transition by filing out the inlet manifold, however you are still stuck with the overall smaller manifold bore. I spoke to Dave Baker at Puma Racing who reckoned that the effort of smoothing out this transition was just not worth it as overall flow will be dictated by the manifold size and the step up where it meets the head will not have a marked effect on performance. What is not known is what effect the smaller manfold size has on performance but unless you felt like fabricating a custom manifold then there is really no choice in the matter. I reckoned that this manifold will happily flow 130BHP on the RS1800 engine so the effect may not be massive, unless I get the car on a rolling road I?ll probably never know. If anyone wants to offer me a free power run on a local rolling road I wouldn?t turn them down.
The 1.6 Throttle body is way too small so you have to use the Mondeo throttle body which happily bolts on to the 1.6 inlet manifold. You do however have to swap over the throttle linkage and the cable retaining plate from the Fiesta Throttle Body. I was told this is a straight swap but in my case this was only partially true as I found I had to cut/file lumps off the cable retaining plate and also found I had to file out the main throttle linkage bore as the Fiesta one is too small for the Mondeo spigot. I think I could just have swapped the spigots over but just could not undo them.
You also need to use the Fiesta dipstick tube as the Mondeo one would foul the Fiesta exhaust manifold.
If, like me, you already have a 1.6 Zetec in the car then you can just use the Fiesta mounts as they are. If you have a CVH then you will need to mod the engine mounts I believe as discussed on the web sites previously referred to.
Those who have done this conversion in a Fiesta will know that you have to also change the oil pump because on the Fiesta it angles in to clear the chassis.
The Mondeo engine I bought was an automatic and as such came with no flywheel so I used the 1.6 flywheel. I believe that even if you use a Mondeo manual engine you still have to swap the flywheel as the Mondeo one is too large for the BC gearbox which was already fitted to the car
The Mondeo starter motor is fitted to the rear of the engine whereas on the Fiesta engine it?s at the front which means you have to use the Fiesta one but it just bolts straight on. The only downside is you are left with a small gap at the rear of the engine where it meets the gearbox and one less gearbox mounting bolt. The lack of one bolt I don?t reckon will be a problem and I made up a blanking plate to cover the resulting gap.
I used the beige Mondeo injectors as opposed to the black Fiesta ones but retained the Fiesta fuel rail and Pressure relief valve, they are the same on the Mondeo anyway
All the sensors are pretty well interchangeable as far as I could tell with the exception of the obvious one which is the Mass Air Flow Sensor that is a significantly larger diameter than the 1.6 unit, however this is a straight swap for the Fiesta one. I also used the Mondeo idle stepper motor and also retained all of the Mondeo engine sensors.
The big one to watch out for that I missed is the Crank Angle Sensor which is fixed to an alloy housing which is bolted to the rear of the block. Because I used a Mondeo Automatic the sensor is fixed at a larger diameter than the sensor holes in the 1.6 flywheel I used. I didn?t realise this until I came to start the engine and had no spark or fuel. The solution was to change this alloy housing to correctly re-position the sensor. The bad news was that I had to remove the gearbox again to change this!!!!!
Crank Angle Sensor Mounting Block?Beware!!!
So was it all easy and was it all worth it???
Undoubtedly yes, the whole conversion took around 4 days in total and I reckon a mechanic used to dealing with Fiestas could have the job done in 3 days. The difference in performance is significant as you would expect having gone from 85BHP to somewhere nearer 130BHP along with the associated ramp up in Torque.
Using the 1.6Si gearbox means that the car tops out at around 125mph , I have been told that by using the RS1800 box I could expect to see 140 mph at the top end but personally I am happier having the better acceleration offered by the Si gearbox as opposed to a higher top speed. I have also found that the Torque on tap means that 1st gear has become nearly redundant and that the car pulls really strongly in all the gears.
So what did it all cost & was it worth it??
Not too bad really given the fact that I already had a 1.6 Zetec engine to start with, for anyone who already has a 1.6 Zetec engined car the it?s a no brainer. If you do not already have a 1.6 Zetec then sourcing all the zetec bits you need could be difficult but if you could find a complete say siezed engine or the like cheap then it would not be so prohibitive.
My Mondeo engine cost me ?460 and the manual ECU I picked up out of Loot for ?25 which was a bit of a bargain. In addition to these there were the usual collection of Gaskets, Oil and Filter, Antifreeze, Plugs and it?s surprising how these add up. I also hired an engine hoist for two separate days. So all in all I reckon the conversion cost me around ?600 in total which the way I look at it for an increase of 45BHP ie 53% over the 1.6 Zetec is a bit of a bargain when compared to say a Weber Alpha Carb or Throttle Body and engine management conversion which would have only got me to around 125BHP and would have cost roughly twice as much.