Instructables

Step 12: OK, now the hard part. Putting the belt back on

I recommend finding a friend. Because you are a DIYer, you won't have a camshaft holding tool the cams are no doubt going to pop out of alignment because of valve spring pressure. What complicates things further is that the intake cam wants to spin clockwise (when facing them head on) while the exhaust cam will pop in the counter-clockwise direction. My hands were full on this one because I did not have a friend available - this is a tough one.

With the tension off the belt somewhat, remove it from the cam sprockets. Some force may be required if its on there tight.

THIS IS WHAT SHOULD HAVE BEEN IN THE MANUAL WHERE IT SAYS "INSTALL TIMING BELT"

Part A Replace the tensioner, spring and idler as necessary
You really must replace the spring, other than that, make sure these two parts are torque'd down.

Part B Get the belt ready
Get the belt ready for putting it on the sprockets. Just weave it around the motor mount post and just let it sit for a few minutes while you do other things

Part C A few adjustments
Place your hex hey in the tensioner. Adjust the intake cam so the I pip mark is at 90 degrees as shown (this is cyl 1 TDC). Carefully remove your wrench so that it does not pop back out of alignment. Be careful at this point, bumpint the car can pop that cam. Now, 'thread' the belt on the crank sprocket. Pull straight up to keep the treads in the sprocket.

Part D The Intake Cam Sprocket
Guide the belt onto the tensioner. Turn that hex key counter clockwise to give yourself more room to move the belt (hold in position). Now, pulling hard on the left side of the belt (and some tension on the right side to keep the belt from turning the crank), 'thread' the belt on to the intake cam sprocket. Only do it about halfway on to make the exhaust side easier. Hold the right side tight, because if you pull on the left side while the treads are in the sprocket, it will pop out of alignment. The idea is to have enough force on the right side of the belt to keep the intake sprocket aligned by not letting the crankshaft sprocket turn ohmy.gif

Part E The Exhaust side
You can now let go of the tensioner hex key you had there, just leave it alone for now so you are not distracted. Take your wrench and turn the exhaust cam clockwise until the 'E' pip mark aligns with the intake 'I' pip mark. The mark on the exhaust sprocket will be at 270 degrees (this is taking straight up to be 0 and turning clockwise). Now, get a few of the belt treads on the sprocket and push down hard so it does not slip. Hold tight.

Part F Popping the belt on
We are gonna do something a bit weird. We are going to use the intake sprocket as a guide to 'thread' the exhaust side on. Place your wrench on the exhaust sprocket bolt and turn it as hard as you can in the clockwise direction. Turn it until the belt 'hops' onto the sprocket. This is why we only did 1/2 of the belt on the intake side biggrin.gif Once the belt is fully threaded (but not on all the way just yet), use your hands to push the belt onto the idler pulley. Take a quick rest if your arms are tired tongue.gif

Part G Aligning the Belt
The belt will slide as it is. Remember that the sprocket before the current one is the guide. So, using a soft mallet, tap the belt a few mm at a time on the intake side - then hand crank the belt. You can do the same thing on the tensioner pulley location, idler pulley location and crank location. Just don't go too far at once to avoid stressing out the belt. Once it is on nicely, hand crank until you see how everything aligns. If the crank notches align when the intake/exhaust pips align, you did an excellent job. Hand crank at least 4 time just to be sure.

I used my jack handle to tap everything in.

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If you have an assistant, use their steady hand when you feel you need a third, fourth or fifth hand. This is the method I came up with. I've never done a timing belt before so I had no clue. And at the time the site was down for us regular members (mazda626.net) :/ Once I did this, it took me one shot to get it aligned right, but the cams do like to pop a lot - so that was a delay.

If you want to make your own cam holding tool, you can. Just use two wrenches that fit the sprocket bolts. Drill a hole in the middle and put a bolt and nut through it. Put the wrenches on the cam bolts, then tighten the bolt in the wrenches really really tight... voila.
 
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neb66 years ago
This was a great walk through. I really appreciate the extra mile. My brothers water pump was not bolted up to the block as the idler pulley bolt was too long. Anyway, when it came time to dial in the cam-shafts, I took the ends of a spark-plug box and inserted them under the first set of bearing caps to hold the alignment. Just being careful not to overtighten the caps. While this held the cams I pulled the #1 plug and used a long screwdriver to judge top dead center. Also pull the distributor cap to make sure the rotor bug is pointing at the #1 in the firing order. The bottom line is it is worth the performance increase to get the cams truly aligned. Thanks again. I couldn't have done it without you all. Benny aka neb6