Crap!

Well it took until about 2AM last night but she fired right up and has been running great today. In the end I didn't mess with the sprockets, I just aligned all three shafts and jammed the belt on the only way I could get it to fit.

In hindsight she had started running ever-so-slightly worse and making weird noises the week prior to the failure... now I know what to listen for when deciding to replace the belt next time. My odometer is at 106k miles and this may well have been the original belt. I got the car at 70k miles and it had a Gates brand belt, so I assumed it had already been replaced. But who knows.

In case it helps, here are the rough procedures I followed. This differs slightly from some of the other writeups I found, but doing it this way was super easy and straightfoward (just time consuming).

1. Remove upper timing cover to reveal broken timing belt
2. Have car towed home
3. Chock wheels, lift passenger side onto a jack stand, remove wheel and liner
4. Put a piece of wood under the oil pan and jack up the engine slightly
5. Remove the upper engine mount by the timing area. Now engine can be raised and lowered slightly to help you fit your wrenches onto the bolts for the rest of the job.
6. Remove the serpentine belt, the water pump pulley, and the idler pulley that's on the mid timing cover. It's easiest to loosen the water pump pulley bolts with the belt still installed.
7. Remove harmonic balancer pulley from crankshaft (18mm, lefty loosey) You normally need an impact wrench here (or to bump it loose with the starter), but mine popped off by hand when I was trying to decide if I could get away with using a 3/4" impact socket on it since I apparently don't have an 18mm impact socket.
8. Remove the mid and lower timing covers (3 x 8mm mid, 2 x 8mm lower)
9. Remove broken timing belt, the timing belt idler pulley, and the timing belt tensioner.
10. Remove valve cover: disconnect VCT actuator, remove throttle cables, remove spark plug wires, disconnect breather vent tube, and unscrew all the 8mm bolts around the valve cover. Blow out debris from around spark plugs before removing the cover.
11. Remove spark plugs
12. Reinstall crank bolt and use it to rotate the shaft to TDC. A screwdriver placed in the #1 spark plug hole provides the most accurate indicator. Make sure to approach TDC with a forward (clockwise) motion.
13. With a 15/16" wrench, rotate each cam to the correct orientation, then insert the cam alignment tool. The tool will only fit the correct way. Do not attempt to turn the cams with the tool installed.
14. Open the new timing kit and realize that you bought the wrong one, because it has one more pulley than you removed from the engine. Confirm that the belt has the same number of teeth, then measure all the pulleys to convince yourself that you can use the new set (just omit the smaller pulley).
15. Install the idler pulley and torque to spec.
16. Install the tensioner but leave the bolt loose. Rotate its various cams around to move it as far rearward (towards the cabin) as possible.
17. Fit the timing belt, starting at the crankshaft pulley, but only push it partway on at first. Jam a towel or piece of foam between the belt and the housing there to keep it from slipping off or jumping teeth while you struggle above. Then feed the belt around the idler and onto the exhaust sprocket, keeping it super tight. Finish by feeding it onto the intake sprocket and fiddling with the tensioner until it will slip over the pulley there. Then push the belt fully onto each sprocket, and remove the rag from the lower sprocket.
18. Remove the cam lock tool.
19. Rotate the tensioner tab into the slot on the housing and tighten the bolt, then loosen it slightly so you can rotate the adjuster. With a 6mm allen key, rotate the adjuster until the indicator (arrow) is aligned with the line, then snug down the bolt.
20. With your ratchet on the crank bolt, rotate the engine through several revolutions to verify proper operation of the belt. Readjust tensioner if necessary.
21. Reinstall valve cover, VCT wire, breather vent, and throttle cables.
22. Disable fuel injectors and ignition at fuse box and perform compression test (optional but easy to do right now)
23. Re-enable fuel and ignition, reinstall spark plugs, and start engine to observe operation of timing belt. Check that tensioner is within spec during idle. Adjust if necessary (with engine off of course). Then torque the tensioner bolt to spec.
24. Install timing covers, pulleys, serpentine belt, engine mount, wheel liner, and wheel.

For such a complicated job, this was actually one of the most straightfoward repairs I've ever done. The most frustrating part is getting the serpentine belt reinstalled correctly. Glad to know my engine is still in great shape with 160 +/-2 psi across the board.

Now for some photos:

Here is what I meant about the teeth not completely lining up between the two sprockets:

I'm not totally sure how this was resolved, but I just fed the belt counterclockwise from the crank, and cursed loudly until it finally slipped over the idler. Luckily the engine seems to run great.

Here is the alignment tool in operation:


This is sold as Lisle 37410, and it worked perfectly for this job. It also includes a couple of parts that are supposed to help you find TDC, but as reported by ZX2Fast in his very thorough youtube video, this approach is less accurate than the screwdriver method, so I didn't use them. So with that in mind, if you are into making your own tool, this couldn't be simpler. Start with maybe 8 or 10 inches of 1/4 x 1" aluminum bar, and machine one side to a thickness of 0.194"



Here is (I think) the correct adjustment of the new tensioner:


One point of concern was that my timing kit, Gates TCK294A, came with (2) idler pulleys, whereas my engine only uses one. I read online that this corresponds to earlier model years of the Zetec (like through '99?), and that it would have different pulley sizes than I need for my 1-idler timing set. (Mine is an '01.) So, I set about measuring each pulley to make sure I could proceed with the repair with the parts on hand:


I'm very confident that these parts are interchangeable, even though my timing kit came with the extra pulley!

I also double checked that the belts had the same number of teeth; in fact, they also had the same part number.

Ultimately, I decided to re-use my old idler pulley, rather than the new one. It had only 0.001" more runout than the new part, and it was made in a country known for top-quality manufacturing, whereas the new part was made in a large communist country located between Taiwan and Tibet that is known for its inferior manufacturing quality and its deep-rooted disdain for human rights.

Which one would you use?



FYI here is what I mean by "total thickness:"


And here is how I measured the tensioner spring force. Note that this measurement is, apparently, not legal for trade.