From Mechanical Database
|Torque specs & parts:
The ZX2 Zetec is a non-interference engine. This means the valves are not capable of touching the pistons at any time. If your belt breaks, there will not be any valve damage. There are reliefs cut into the top of the pistons that allow clearance for the valves if the belt breaks. Most engines are interference and will cause several hundred or even thousands of dollars of damage when a timing belt breaks. Most shop manuals list the ZX2 as interference but it is not.
Note: if you have issues with the timing belt walking off the gears, then you may have a worn or tapered lower timing gear. The early engines had a two-piece design that was prone to this type of failure. You can update it to the later one-piece model. The part numbers for all the pulleys are listed in the infobox to the right.
- Put the passenger side of the car on a jack stand and remove that wheel. Remove the plastic splash guard that covers the bottom of the car and the passenger side. These are 10 mm bolts.
- Remove the serpentine belt then remove the crank pulley. This can be done without an impact gun. Use an impact gun if you have one, but if you don't, then follow this procedure:
- Use the correct socket for the crank bolt (I think it is 18 mm) with an extension and breaker bar.
- Put the breaker bar and socket on the bolt and brace the breaker bar against the lower control arm. I used another jack stand and a few small boxes. The idea is to have the bar snugly pressed against the control arm and propped up from underneath so it sits square with the crank bolt.
- Now, dis-connect the 3-wire connector at the ignition coil so the car won't actually start. Make sure the car is not in gear and no one is standing near the breaker bar.
- Bump the key about a second in the start position. This should break the bolt loose and now you can go remove it.
- With the crank pulley off you can now see the timing belt gear. Remove the splash shied cover that is behind the crank pulley. It is held by two 8 mm bolts I believe. Also remove the upper timing belt dust cover. These are 8 mm as well.
- Remove the valve cover. Start by disconnecting the VCT connector on top and remove the spark plug galley cover if you have one. These are 8 mm bolts. The valve cover is held on by 8 mm bolts as well. The one on the passenger-firewall side has a stud on it and will require the use of an 8 mm wrench or deep well socket. Do not let the gasket touch the ground. Soak the gasket in WD-40 so it will swell back to original shape and you can reuse it.
- Now we set the cams at TDC. TDC is Top-Dead-Center. It is the higest point in the cylinder that the #1 piston reaches on the compression stroke. If you have the cam locking tool, it will only slide into the back of the cams (driver side) when they are set at TDC. You may have to rotate the exhaust cam several degrees to get the cam locking tool to slide into the exhaust cam. This is normal because of the nature of the VCT. If you need to rotate the cams to get the locking tool in, then put the crank bolt back in the hole and turn the entire crank with that bolt. After the locking tool is able to fit into the intake cam (firewall side) then use a large adjustable wrench (or 15/16" open-end) on the exhaust cam (there are flat spots near the belt for the wrench to fit onto) to rotate the exhaust cam.
- If you are replacing a broken belt or a belt that has otherwise skipped time, then you will have to set the cams at TDC and the crank at TDC separately. If this is the case, then follow the instructions outlined below. If you do not have a broken belt (you are replacing a belt before it breaks or otherwise fails) then you do not have to set the crank at TDC, it will be set when you set the cams at TDC.
- If you need to set the crank at TDC separate from the cams then you can do so with a couple of methods. You can remove the spark plug from the #1 cylinder and insert and long screwdriver into the hole. Then you rotate the crank until the screwdriver is at its' highest point. There will be a point where you can move the crank just slightly and the screwdriver will not go up or down. This is TDC for the crank. One final method that has worked for me is to just set the crank key (the small notch the crank pulley slides over) at the 12 o'clock position. Notice that the engine leans slighty forward. Set it at 12 o'clock in relation to the engines lean. It'll look like 12:10 to you. Since each tooth on the crank pulley is about 16* of timing, it would be hard to be off a tooth and not notice.
- Now with everything set at TDC you can remove the old belt. If the belt has already removed itself (broken) then you still have to loosen the tensioner. Below the intake cam gear you will find the tensioner. It has a small notch on the front with a place to put an allen wrench and a 10 mm bolt sticking out. You have to loosen the 10 mm bolt. It is a small space and this is where a long 10 mm box-end wrench comes in handy. Loosen it about 3 turns and push that allen slot down (it rotates) and this will release tension from the belt. Slide the belt off. To make belt install even easier, loosen the bolt enough to pull the tab out of the back plate. This will give you more slack to work with.
- If you have a pre-99.5 with a two piece crank gear, replace this gear with the single piece gear. Part number is at the end of this how-to.
- Ford put a TSB that fixed some of the issues with the new belt walking off of the cam gears. The problem is that the new belt would bunch up between the gears a bit when the springs loaded the cams and the VCT was being actuated. The fix is to set the cam gears neutral to the new belt. You'll want to remove the cam locking tool to prevent breaking the back of the cams out. Use a large wrench to hold the intake cam in place while you use a Torx bit (T55 I think) to loosen the intake cam bolt. You only need to loosen it enough so that you can move the cam gear free of the cam. Now, use the wrech and the same bit to remove the oil plug from the VCT hub. Put some rags below the hub to catch the bit of oil that will come out. Now, the exhaust bolt can be seen inside the hub. It is an 'E' (inverse torx) bit. I've always just used a 12-point 16mm socket. Loosen the exhaust cam bolt enough to move the VCT hub (exhaust cam gear) free of the cam. Put the lock tool back into the cams and continue with the next step.
- Now we install the new belt. This can be a bit difficult because the new belt is not stretched at all and will prove difficult. You may be tempted to try prying it on with a pry bar (or screwdriver), please resist the urge to do that. After you cuss a lot and the belt slides on make sure it sits just inside the gears the entire length of the belt. Now you can apply tension. Slide the tab into the back plate. Tighten the tensioner 10 mm bolt up just a enough to keep the allen key from falling down under its' own weight. Behind the tensioner is a back plate with a notch cut into it. You can see there is a line it is supposed to point to. Make sure it is pointing to it when you start to put tension on the belt by rotating the allen slot counter-clockwise. Now you need to hold that allen slot with the allen wrench in a 3 o'clock position while you tighten the tension bolt. It is a very small space to work in and it will make you mad, but it has to be done. Get the bolt good and snug, 18 ft-lbs. Don't over tighten it, it might break off. After you get this done you need to check the belt deflection. Just push down in the center of the belt (between the cam gears) and see if it travels downward more then a 1/4 inch. If not, then the tension is set fine. If it won't let you move it at all, then the tension is too much and may cause the belt to break.
- Now that the belt is installed, you have to tighten up the cams gears. Starting with the exhaust cam gear, use a wrech to hold the cam still (leave the lock tool in, but hold the cam in place so you don't break the slots out) and tighten the bolt up to 30 ft-lbs. Now, hold the intake cam still and tighten the bolt up to 50 ft-lbs. Remove the lock tool and tighten the exhaust cam bolt up to 80 ft-lbs. Install the oil plug into the VCT hub and tighten it up to about 15-20 ft-lbs. All of this sets the cam gears to neutral and prevents the belt from bunching up in the center during VCT operation.
- Now you can put it back together. If you haven't already done so, remove the cam locking tool. Rotate the crank with the crank bolt one full turn to make sure the belt isn't going to bind on anything.
- Re-connect your coil plug if you removed it, some people forget then get scared when the car doesn't start.
- When you install the valve cover, you need to wipe the head mating surface down to make sure it is clean. Here is the torque pattern and sequence.
- When you install the crank pulley, use some medium strength Loc-tite on the bolt to ensure it won't come off. Just get it as tight as you can. The engine will move but that is fine. The Loc-tite will keep it from coming back out. This would be a great time to upgrade to and install a UDP for more performance.
The article is provided courtesy of ZX2Fast.