How to change Timing Belt and Water Pump on a Mazda Miata Part 2
September 24, 2004
Now that the valve cover is off, the real fun begins!
5. Remove Crank Pulley
You're going to need big guns...(i.e. air tools)
I bought this air ratchet because I figured my impact wrench wouldn’t fit between the AC Condensor and the Crankshaft pulley.
Unfortunately this little ratchet can’t produce enough torque to break the bolt loose, but I was able to fit the impact wrench (barely), using a non-impact socket. This is something you should never do. I knew that, so I wore safety goggles (er, um, I mean, I continued wearing my safety goggles) while using the wrench, expecting the socket to shatter at any moment.
I had to lower this suspension bar about an inch in order for the impact wrench to fit. Don’t do this unless you absolutely have to, it is more trouble than you would expect.
The socket didn’t break, but in the process of breaking the bolt loose I managed to smash the impact wrench into the AC condensor, denting it a bit.
Here is the crankshaft sprocket that hides behind the pulley that was just removed.
6. Remove Timing Belt Covers
There are only a handful of screws holding the 3 covers on.
(Please disregard the fact that the crank pulley is back on in the picture above)
7. Set engine at TDC (Piston #1)
It’s always a good idea to find TDC before removing the timing belt just to make sure all the markings are correct. If they aren’t correct, you’ll probably want to make some markings of your own for reference (assuming the car ran properly before you started this job).
Note the “I” and “E” marks on the cam sprockets and the black plate behind them. These are the valve timing marks.
You will need to align the marks on the cam sprockets with the marks on the backing plate before removing the belt. I do this by putting the crank pulley back on without the bolt (the woodruff key keeps it from spinning freely on the shaft). Remember to always turn the pulley clockwise (this is the way the engine turns).
Here are the sprockets at TDC. Note that notch above the “E” on the intake sprocket (left) lines up with the line under the “E” on the backing plate. On the exhaust side, the letter “I” is used to match up the sprocket to the backing plate. Be sure to note the position of the cam lobes before removing the belt. I believe that the valves are all shut for cylinder #1 (the one closest to the front of the car) at TDC. I did not pay enough attention to the position of the lobes and I ended up putting the exhaust cam sprocket on in the wrong position, which led to the car not starting when I put it all back together.
9. Remove the Timing Belt
It comes off relatively easily, especially when compared to putting it back on!
Note the two pulleys touching the belt from the outside (non-ribbed side). One is the tensioner pulley and the other is called the idler pulley. You’ll want to remove all tension from the belt by loosening the bolt on the tensioner pulley (the one on the left, I believe), then moving the pulley away from the belt and re-tightening the bolt.
This is what it looks like with the belt, idler pulley and tensioner pulley removed.
10. Remove camshaft sprockets and backing plate
This step is only necessary if you are replacing the water pump. Even then it might not be necessary.
You can see some of the bolts holding the backing plate in the picture above.
Be sure to mark the positions of the cam pulleys relative to
the camshafts before removal!
Here is my engine with the cam sprockets removed (note the position of the lobes, I believe they are already in the wrong position here. The ones on the exhaust side should be pointing to the right for cylinder #1, if my memory serves me correctly.
Here is what to do with the power steering pump: remove the big bolt that connects it to the engine, then tie the pump out of the way. I moved the airbox to make this easier.
The airbox is a bit tricky to move out of the way because of the snorkel, but if you wiggle it around just right you can move it without breaking anything (be especially careful with the airflow sensor, apparently it is very fragile).
Here, the backing plate has been removed, along with some of the bolts holding the water pump in place. Oh, I also removed that silly goose-neck thingie that connects to the upper radiator hose.
11. Remove Water Pump
This is a bit tricky, but not too bad. There are a few obvious bolts in the front, as well as a tricky one over to the right side. In fact, the tricky one is so tricky that I can’t remember the trick to it, so you’re on your own here…..come to think of it, maybe it was just slimy and not really all that tricky….
There is a water-inlet pipe on the right side of the water pump. You will have to wiggle the pump assembly around a bit in order to disengage this pipe and remove the pump.
You can clearly see a bit of the water inlet pipe in the picture above. It is the pipe that leads to somewhere behind the exhaust manifold. It lines up with the rusty bolt on the heatshield.
12. Make Pile of Parts for Neighbors to Admire
If you thought your neighbors were impressed by the car on jackstands and the large puddles of toxic fluids you created in your driveway, just wait til they see the pile of used parts you have accumulated while changing the timing belt. Of course, most of these parts will be going back into your Miata, but no one has to know that. If you leave the parts out in the weather for a few days you’ll soon convince everyone that you are converting your shanty/bungalow/mansion into a not-for-profit junkyard!
It also helps to throw in other car parts, such as the lone brake pad in the pic below. I think the $3 garden hose also adds to the ambience.
13. Throw Water Pump into Pile, admire color of Antifreeze
You have successfully reached the apex of the dissassembly. If you are like me, this does not by any means imply that the destruction has reached an apex as well. To the contrary, I may have not destroyed anything at all (except for part of the radiator and a few bolts here and there) at this point. For me, reassembly is by far the most destructive phase of the repair process.
For some reason the picture above really gives me a warm, fuzzy feeling inside. I really like the way the antifreeze looks just sitting there in the engine, waiting to get all over me and my driveway at the slightest provocation…
14. Install new Water Pump
Don’t forget to clean all gasket mating surfaces before installing the new water pump. Also, don’t forget to use the right type of sealant (water pump sealant). I can’t remember if I remembered to use the sealant, but I do remember that I had antifreeze shooting all over my engine for a different reason after I finally got the car back together and running…
I definitely think I forgot to take pictures of the installation of the water pump, but it is more or less straightforward, with one caveat: the water inlet pipe o-ring. There is an o-ring on the end of the water inlet pipe. Put the o-ring on the inlet pipe on the new pump, and try to get the inlet pipe matched up properly when you install the pump. I somehow managed to screw up the installation (or the new o-ring was defective to begin with), and I ended up with a lot of coolant leakage. Luckily, I was able to replace the o-ring with the old one by removing the heat shield from the exhaust manifold in order to access the other part of the hose.
15. Reinstall Backing Plate and Cam
Sprockets
Think the worst is behind you? Mwahahahaha! It is now time to put it all back together again. As I mentioned earlier, I managed to put the exhaust cam pulley on wrong (since there’s no reason to have 3 different possible positions of this pulley, I assumed there was only 1 possible position and therefore neglected to mark the position of the pulley in relation to the shaft). Even if you screw up like I did, the sprockets are very easy to reinstall.
16. Install Timing Belt
This is a total bitch. I don’t think it is humanly possible to get the belt on correctly on the first try. I think my new belt looks worse than my old belt just from the wear-and-tear involved in putting it on so many times. Because of my cam-sprocket screwup, I ended up redoing the entire timing belt portion of this job 3-4 times, and every time I took at least 3 tries to get the belt on with all the timing marks lined up properly.
Here are the steps involved in installing the timing belt:
· Align the crankshaft timing marks. Don’t worry if the crankshaft turned while the belt was off; TDC for the crankshaft is TDC (regardless of whether it is on power stroke or intake stroke) on this car. I say this because the “crank position sensor” is actually connected directly to the exhaust cam (I believe it was connected to the intake cam for 1.6 liter models).
· Align the cam sprocket timing marks. The intake cam sprocket (left) should have the “I” at 12 o’clock and the “E” should match the mark on the backing plate at approximately 4:30. The exhaust cam should have the “E” at 12 o’clock and the “I” matching up at about 7:30.
· Have an assistant hold the camshafts in place with gear wrenches. As annoying as it is that the intake camshaft jumps from TDC unless it is held there, it is really nice that Mazda gives us dedicated flat sections on the camshafts to allow us to use a wrench to hold the shaft. For whatever reason, I was never able to install the belt correctly using this method alone. This is where my alternative comes in…
Paul’s Alternative Timing Belt Trick: Put long screws into
the holes in the backing plate behind the cam sprockets. These lock the sprockets
in position (within a few teeth, at least). This allows you to use a gear
wrench on the camshaft for fine tuning while the belt is installed.
· Slide the belt onto all three sprockets while trying to keep the timing marks lined up. Like I said earlier, you will probably need to do this many times before you get it right. If you are a tooth off, the engine won’t run properly.
· When you get the belt on with all of the timing marks aligned correctly, turn the engine two revolutions (you’ll want to put the crankshaft pulley on to facilitate this- just don’t tighten the bolt yet.
· If everything still lines up, have someone else take a look just to be sure. If the marks don’t line up, remove and install the belt again.
· Double check the timing marks again. Because you don’t want to remove and install the belt again (unless you’re a real sicko), you will tend to see everything lined up perfectly even when it isn’t. This is analogous to religious people who want God to exist so bad that they end up believing coincidences are actually proof of the existence of God. Just like the “faith” in God, the “faith” in the alignment of the timing marks is total bullshit. Do yourself a favor and have someone else take a look. Take a picture before and after you remove the timing belt and have someone else compare them.. If nothing else, at least take a good long break from working on the car and then double-check the marks before going on to the next step.
I used long screws to help hold the cam sprockets in place, and c-clamps helped secure the belt to the sprockets during installation.
The picture above shows the timing marks on the cam gears aligned properly with the marks on the backing plate.
Below you can see that the crankshaft timing mark is also perfectly aligned (the arrow matches the notch perfectly at 12 o’clock).
17. Reinstall everything else
Hopefully you can remember/figure out how to put everything back together from this point, because I’m certainly not going to tell you. Don’t forget to tighten up the bolt on the crankshaft pulley.
You shouldn’t need to mess with the ignition timing at this point. If the car runs poorly, there is a good chance that you are a tooth or two off. If it won’t start, you’ve got bigger problems (like your cam sprocket is mounted incorrectly). The ignition timing wouldn’t have changed when you changed the belt, so it is highly unlikely that ignition timing is the culprit.
Don’t forget to keep all of the old parts in your car for the first few weeks or several hundred miles, just in case you end up needing one (I needed the old o-ring, boy am I glad I didn’t throw that away! I’m way too tired to write anything else even mildly coherent at this poing…..point…..
