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 Tuning the ZetecLast  on September 24 2008NEW Engine Build Follow the build of my 2.1 Zetec-E here 
Want to know what the options are for your Fiesta, Escort, Puma, Mondeo or Focus? Then read on.
The base spec 1.8 litre Zetec makes about 115bhp in standard trim. The 130bhp 1.8 is the same engine fitted with different camshafts, and this engine can be found in the Fiesta RS1800i. The cams are interchangeable, so a 115bhp unit will become a 130 with the addition of the better cams. The 2.0 engine is the engine to go for. It makes around 135bhp as standard, but theres so much more available. Ford uprated the Zetec during 1997/8 model year, following its introduction in 1992. The earlier engines known as Silver Tops (ST's), thanks to their plain aluminium cam covers, with later engines being known as Black Tops (BT's) because of their black cam covers. BT's have two piece sumps whereas ST's make do with a one piece design. Changes mostly relate to the front of the engine. ST's have a standard water pump which bolts on to the engine, but BT's have a cartridge type pump that sits in the cover itself. All engines since 1996 have a concentric hydraulic clutch release bearing. The Zetec weighs in at 115Kg as opposed to the Pinto which weighs around 133Kg. ST170 Although the engine fitted to the Focus ST170 has Duratec emblazoned on the cam cover, it isn't one at all. Fords marketing department presumably decreed that their top-of-the-line performance variant couldn't have an engine of older design than the cooker models, and so they dressed up a Zetec to look like the engine that replaced it. The Duratec is an all alloy engine with chain-driven cams and the induction and exhaust on opposite sides of the head. The ST170 engine is basically a trick Zetec with a stronger bottom end and variable inlet cam timing. Some specialists say that the engine cannot be transplanted because the cam timing is controlled by the ECU in the Focus. However, one way of altering the cam timing would be to use the shift change lights output from an ECU for instance. Block, crank and rods The reason the Zetec lasts so long and is so reliable is because it's built to standards that ordinary car engines just weren't built to 20 years ago. The tolerances, materials, machining and assembly are in a league that your average Pinto can only dream about. There have been engines with mileages of 170,000 reported with honing marks still on the bores. If you do manage to find a knackered bottom end, dont bother trying to recondition it. The engine was developed with Yamaha and the boring/honing process of the iron block is very hard to replicate. It can be done, but as you can buy a brand new short engine for £500 there's little point in reconditioning and old engine, unless you are going for an overbore of 2.1 litres. This can be done using Vauxhall XE pistons. The bottom end of the Zetec is good for 7000rpm in standard form and, with the addition of ARP bolts, 7400rpm is no problem. Thats about the limit for a road engine but if its a top spec race unit you want to build and you are looking for more than 200bhp, then you'll need forged pistons and steel rods in order to safely rev higher than this. Starter motor and alternators Zetecs are usually saddled with a 60 or 70amp alternator to cater for a modern cars' power-hungry electrical system, with their electric windows and air conditioning. The problem is that it will probably get in the way of the carbs or throttle bodies you want to use. However, you're unlikely to need an alternator with that much power so to gain some more room you can replace them with a Lucas or Brise alternator. I'm using the Brise version, which is a very tiny 49A model. Starter motors are pretty straightforward as one from a Ford CVH engine (Lucas part number LRS707) will bolt straight on. You can also use one from a Pinto engine, although it will need a 14mm spacer between it and the engine to give the correct pinion throw. Heads and cams Like many four-valve modern heads, the alloy Zetec unit is pretty good straight out of the box. It has good tumble which allows it to produce a healthy torque curve but that is not to say that gains can't be made. Careful porting can provide worthwhile flow improvements and there's room for bigger valves if you're after more than 200bhp. A standard head (on a 2.0) with side draughts or throttle bodies plus mapped ignition will make between 160-170bhp. Port the head and add some 285° cams for 200bhp. With big valves and careful gas flowing you can squeeze 220bhp. You'll need vernier cam pulleys to get the best out of even standard cams. Sumps There are plenty of cars out there with RWD Zetec installations using a standard 1.8 litre sump and its associated pick up pipe. For road use his works fine. However if you are planning the odd track-day or want to go racing you need a sump modified to suit RWD. These are available (together with dipstick and dispstick tube) from several vendors. Dont go too big on oil capacity. The Zetec needs to run oil temperatures of above 100°C which is why it only has a 3.8litre sump capacity. If the oil temperature falls below this engine wear increases rapidly. ZVH Turbo conversion There's a popular engine conversion available in the UK, called the Zee-VH. This involves combining the Ford Zetec engine block and crankshaft, and the Ford CVH cylinder head and water pump. Sounds strange? Well, its popular amongst the Ford Escort and Fiesta Turbo owners. It allows them to build a higher capacity engine than the original CVH engine (1600 cc) and it also allows them to retain the original manifolds and Turbo system. Figures of up to 270 BHP have been quoted with this straight forward modification. Jim Hearne is currently producing some information on the Zee-VH and rather than re-invent the wheel, follow this link to Jim's site for all the technical details Zee-VH information page. Another engine conversion that follows the Turbo route, is of course the Zetec Turbo, where the 16V head is retained. An excellent website that concentrates on this conversion is www.zetecturbo.com. Well worth a visit. Sunny Khalsa's Zetec Turbo powered Mk3 Fiesta recorded 178MPH at Bruntingthorpe in September 2003, and he is planning to break the 180MPH barrier for a front wheel drive car in 2004. Another excellent web site full of photos and technical information on the Zetec, is Mark Stewarts site. www.mstewart.co.uk. Mark has spent a lot of time and effort documenting the differences between the revisions of the Zetec and the newer Duratec engines. An excellent site. Physical dimensions Exacty how big is the Zetec engine? Well, you'd probably be surprised that it's not a great deal bigger than the X-flow. It is slightly taller, and longer, but not that much bigger.
These pictures show the rebuilt 2.0 Zetec engine, ready to go back in to the Fiesta (September 2000). 
Water pump warning !! You need to be aware that the water pump on the Mondeo 2.0 Zetec engine is driven by a serpentine belt, and as such, rotates in a different direction to the Fiesta/Escort pump. The pumps look identical on the outside, however, inside, the impeller is a mirror image between models. This means that the water is still pumped through the engine in the same direction on the Mondeo and the Escort/Fiesta, despite the pumps turning in opposite directions. Therefore, you must make sure that the pump you use is designed for your installation. If you're using the serpentine belt drive, then use the Mondeo pump. If you're using the triangulated drive system (ie crank, water pump, alternator) then you must use the Escort/Fiesta pump. The outlet pipe on the Mondeo water pump, exits the front of the block at an angle, but the Fiesta/Escort pump outlet pipe exits in a straight line. For the later black top, or series 3 Zetec from the Focus, the solution is a reversed impellor from a place called Quicksilver Race Engines in the States, or an idler pulley made up to run the pulley in the same way as stock. The two pictures below show the two different arrangements for driving the water pump. The serpentine system, as used on the Mondeo, and the triangulated system, as used on the Fiesta. Key to pulleys: A = Alternator, W =Water Pump, C = Crankshaft  The Serpentine system The Triangulated systemFitting a replacement air filter The standard air box on the Mondeo, or any standard Zetec powered car for that matter, is designed for two things. The first is to supply filtered cold air to the engine, and the second is to keep the noise (induction roar) down to a minimum. Therefore the shape of modern air boxes is a compromise. Air (at normal atmospheric pressure) has to pass through the box, around bends, over sharp edges, and often through a series of corrugated pipes. These all cause turbulence, and restrict air flow to the engine. On a normally aspirated engine, the engine sucks air through the carburettor, in to the cylinder. Turbo charged cars have the air pushed through the carburettor, in to the engine, and don't suffer as much from poor air filter design. Exhaust gas is used to drive a turbine, which forces air through the carburettor. A Dump Valve in the path in to the carburettor, prevents excessive pressure from building up, otherwise the engine would continue to rev above a safe limit, and would explode. Note: Induction roar is caused by the sound of air being sucked in to the engine. Its the 'slurp' that can be heard on any racing car when the throttles are opened, and at full throttle, develops in to a quite a loud roaring sound. Modern cars are designed to be as quiet as possible, and the designers have a difficult task in reducing the noise caused by induction roar. If you want better performance from your engine, then you need to be willing to put up with a small amount of discomfort by way of extra noise, for those extra horses. If you could replace the standard air box, with a free-flow air filter, the engine will be a lot more responsive, but a little noisier. Fitting an aftermarket induction filter kit is a very easy way to unleash a few extra horsepower. The air filter that I'm fitting in this article, the True-Rev Sport Induction Kit, is produced by a company based in Kansas City, called Kurts Kustomz Motorsports. The filter kit in question is designed for the 1.8 and 2.0 Mondeo engine, but they also supply kits for the 2.5V6 Duratec engine. Check out their web site for more details. The air filter element plays an important part in the lifetime of the engine. Some people don't run an air filter at all. The risk with not running an air filter, is that a stone could enter the engine, which will wreck the head, valves and pistons and anything else it comes in to contact with. Take my advice, always use an airfilter. Not only does it prevent large objects from being ingested, but it also filters out grit and grime from the air, which also helps prolong the lifetime of the engine. The KKM filter is a lifetime unit, (and needs cleaning every 15K-30K miles depending on the environment you live in) and when you look at it, it has a much greater surface area than the standard airbox filter supplied by Ford. These types of filters are designed to bolt straight on to the induction system, which allows you to remove the ugly airbox. 
Picture one shows the original induction system on a British Ford Mondeo 1.8. The air enters the box from the front wing, passes through the box, across and through the air filter, and passes through a MAF unit. This device measures air-flow in to the engine. The air then continues through another unit, which is where it crosses a thermistor. This device measures the air temperature. The air then goes in to the intake plenum, where it is drawn in to the engine. Picture two, three and four shows the new KKM induction kit fitted in place. Its so simple to do that it doesn't really warrant extra photographs. To replace the airbox with a freeflow filter, start by disconnecting the battery leads. Next remove the airbox lid, and take the standard filter element out. Be careful not to disturb it too much, as there usually a lot of grit in the filter, and you don't want it sprinkled all over the engine. You need to disconnect the oil-breather pipe that runs from the rocker-cover to the bottom of the air box. Now remove the large pipe that connects the MAF unit to the intake system. Loosen the jubilee clip, and separate the MAF from the hose. The airbox can now be lifted upwards, and removed. Now carefully remove the MAF from the airbox. Don't drop the MAF Unit, as they're fragile and expensive to replace. OK, next stage is to carefully fit the blue silicon hose to the aluminium elbow. Use the jubilee clips provided. Connect the silicon hose to the MAF unit, and then connect the airfilter to the other side of the MAF. Note that the MAF has an arrow on it, indicating the direction of air flow. Make sure that you put it back on the right way round. There's a small bracket with supports the MAF and filter, which you must fit. Finally, a small chromed air filter is fitted via a piece of rubber tubing to the oil-breather outlet on the back of the rocker cover. It only takes approximately 15 minutes to dismantle the old airbox, and fit the new unit. I must say that the performance increase is quite staggering. There is lots more bottom end grunt, and the engine really comes on to the cam at about 3500-5000 RPM, with lots more torque for overtaking. Fuel economy has also improved, which is surprising. Noise has increased slightly, and there's a nice roar at 4500 RPM. The KKM air filter looks a lot more professional than the K&N Unit that I've seen on some cars. The K&N is just a cone, whereas the KKM filter is a much larger unit. Which must mean there's less resistance for air to flow through, and much more potential for extra horsepower than the K&N unit allows. Use the correct grade of engine oil Theres three different series of Zetec engines used in the UK. Series 1 was on the earliest Mondeo's, up to about the beginning of 1995. The S1 Zetec can be identified by "DOHC 16V" cast in to the rocker cover. These early engines are prone to sticking valves, especially at startup when the engine is cold. Later Series 2 engines have "16V Zetec" cast in to the rocker cover, and this engine does not suffer from the same problem. I had loads of problems with my Mondeo when I serviced her in June 1999. After spending two days at the Ford dealer in town, they diagnosed that the engine was running on the wrong grade of engine oil. I'd followed the guidelines in the handbook, and checked in the Haynes manual, and they both say to use 10W40 synthetic oil, which is what I used. It transpires that the oil should be 5W30, which is thinner at low and high temperatures. My engine had been misfiring at startup, and stalling. This was due to sticking valves in the cylinder head, caused by the oil being too thick when cold. Top marks to my garage in spotting this. Black mark for the Ford and Haynes manuals. Stranger still is that the pinking (pre-ignition) also seems to have been cured! Have you checked which grade your engine is running? Change the rod bolts A particular weak point on the Zetec engines are the con-rod bolts. A lot of Zetec engines have lunched themselves because the rod-bolts have sheared under high load, and changing them is not a difficult or long job. You just need to buy a set of ARP rod bolts from Raceline or Burtons, and a new rubber sump gasket. Drain the oil from the sump, drop the sump off the engine, and replace the bolts, making sure to torque them up to the required level. Then replace the sump gasket, refit the sump, and refill the engine with oil. 
Change the camshafts and fit vernier pulleys March 2004: The standard 2.0l cams are good for around 165BHP running on after-market fuel injection. I'm sponsored by Piper Cams,, and they've provided a pair of BP270BH's which work well with standard cylinder heads and pistons. With these fast road cams, there is no need for additional piston cut outs, and they're good for an extra 16 BHP over the standard cams. This guide is intended to assist you with the task of replacing camshafts on the Zetec engine. I take no reponsibility for any problems you may have when following the guide. I've double checked everything here, but like everything on the world wide web, articles are prone to error, though hopefully there are none below. You can change the cams when the engine is warm if you wish, but for your own safety I'd recommend that the procedure is followed on a stone cold engine. Otherwise you may burn yourself on hot oil or other mechanical parts.
Fitting the new cams
Once both the camshafts have been replaced, you need to time them according to the specifications supplied by the camshaft manufacturer. The Piper BP270's that I've used are both set to give full lift at 110°. That is, after 0° TDC (ATDC) for the inlet cam, and before 0° TDC (BTDC) for the exhaust cam. [Note: TDC means Top Dead Centre and describes the position of the piston being at the top of the stroke, with the crankshaft at either 0deg; TDC or 180° BDC = Bottom Dead Centre] To make this easier to picture, if you imagine that the #1 piston (nearest the water pump) is moving up the cylinder on the exhaust stroke (eg expelling all the exhaust gasses from the #1 cylinder), the exhaust camshaft opens the exhaust valves fully as the crankshaft is rotating (clockwise as you view the crankshaft pulley) and when the position of the crankshaft pulley is at 110° before top dead centre the exhaust valves are by now fully open. As the piston continues upwards and it reaches TDC, the exhaust valves should now have fully closed, and the piston now drops down inside the cylinder, and as it does so the inlet valves start to open, and only when the crankshaft is at 110° after top dead center are the inlet valves for cylinder #1 fully open. Then as the crankshaft continues to rotate, the inlet valves close, and the piston is pushed up the cylinder, on the compression stroke. When it reaches TDC (or near) the spark plug fires, and ignites the mixture, and the explosion pushes the piston down. Once it goes down the cylinder past BDC, and starts to rise again, we repeat the whole cycle with the exhaust camshaft starting to open the exhaust valves, which allows the piston to force the exhaust gasses out past the exhaust valves and in to the exhaust manifold. And so on. If you can picture all this, then you can see that the exhaust valves open fully before top dead centre (BTDC), and the inlet valves open fully after top dead centre (ATDC). The timing angles given by the camshaft manufacturer is critical. Both camshafts are designed to operate at precise points during the rotation of the crankshaft, so it is very important that the camshafts are timed in accurately. To do this, you must use a set of vernier pulleys. The stock pulleys have no adjustment in them, and once they're locked in place at 60ft/lb torque with the pulley bolts, its impossible to make subtle changes to the timing. Vernier pulleys allow adjustment +/- to 1/10ths of a degree so you really can set the positions much more accurately. OK, sermon over. Lets have a go at timing the new cams in (There's nothing to be afraid of, it's a straight forward procedure, using mechanical alignment and adjustment.) You will need a timing disk (disk showing 360 degree markings); a piece of stiff wire to act as a marker for the timing disk; a dial gauge and stand; cam-lube. HINT: to make the task of timing the cams easier, once you've refitted the cams after drilling and fitting the dowels [see below], coat the cam lobes with cam lube. This treacle like liquid protects the cam lobes from damage during the running-in period, and also stops the cams from rotating when you release your grip after rotating them by hand. Without the cam lube they tend to snap back to a different resting position when positioning the cams by hand. Timing in the cams
Once you've done all this, you will need to drill and fit the supplied steel dowels so that the centres of the new vernier pulleys cannot rotate on the ends of the cams, should the pulley bolts come loose. Mark the position of the hole through the hole in the aluminium vernier pulley, and remove both the cam shafts. This will undo all of the above work, but not to worry, practice makes perfect. Carefully drill 6.5mm holes in the ends of the cam shafts, where you marked them, and fit the dowel pin using threadlock to stop them from falling out. Refit the cam shafts to the engine, refit the pulleys, and repeat the timing procedure above. Once complete, tighten the cam shaft retaining bolts to 50-60ft/lb. Rotate the engine another couple of turns, and use the vernier pulleys to accurately set the timing to that specified by the manufacturer. Remember: Once you've set the cams up, you should still get the car dyno tuned, so that the dyno operator can swing the cam timing to get maximum power from the engine. That's really is all there is to it. If you've followed the above carefully, and you're confident that the valves are opening without hitting the pistons, you could spin the engine over on the ignition now, without the plugs fitted, and you should find that it spins over nicely, with no problems. Next step is to pour more cam-lube over the cam lobes, refit the cam cover, plugs and plug leads, and start the engine. You must run it at 2000rpm for 20 minutes when you first run the new cams. This will bed them in. You may hear some tapping when you first do this, its just the tappets and the new cam lobes working against each other, and after 10 minutes or so it should quieten down. |
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