I recently completed my third timing belt replacement job, my first on my 2002 Protege5. I started in mid-November, at 117,898 miles, and completed on February 5th. I also drive a 1991 Nissan 300ZX, so there was no time pressure. Lotsa honey-do's, Thanksgiving, Christmas, New Year's and frustration breaks. I was very surprised at the excellent condition of the original Mazda OEM belt after tearing down to that point. It could have easily gone another 10 to 20k miles.
After I replaced the cam oil seals, crankshaft front oil seal, water pump, idler roller, belt tensioner assembly & spring, I set about fitting the new timing belt, using a Mazda OEM (Gates USA) timing belt. I also had a Conti-Tech belt which came in my TBK, but just felt more comfortable using a Mazda part-numbered belt. Hopefully, it will hold up as well as the original Japanese belt did. So, the Mazda shop manual suggests to start the belt at the bottom, route the belt to the right, tucking the belt inside the idler roller, wrap around the exhaust cam sprocket, then up & over the intake cam sprocket. Of course, making sure the belt is tucked in at the tensioner roller, and the tensioner is giving the belt maximum slack (spring disconnected at the pin). There wasn't any way in hell that new timing belt was going to mount that way. It seemed like the belt was about an inch short. I kept that belt over the back of my computer desk chair for about two weeks to warm up & stretch (if they actually do). I made five or six attempts at mounting the new belt this way, and then tried about five more times going from the top down, securing the belt to the cam sprockets with tie wraps & going down through the rollers. Still no joy, the belt would have to be pried on at the crankshaft pulley. That method is a no-go. Gates USA website has training videos that emphasize belts can not be pried on with tools, it over-stresses the Kevlar & Rayon fibers that give modern belts their durability. After these attempts, I took a break for about two weeks. One day I had an idea : with the tensioner pulley removed, could I mount the belt ? Could I create enough slack in the back side of the belt to bolt the tensioner pulley back on, & how the heck would I re-hook the spring ? Should have mentioned earlier that I locked the cams in place right after removing the camshaft cover, using two 8" Crescent wrenches pinched together with a C-clamp. This method locked the cams solid. The old belt mounted on easily, and when I pulled the back side of the belt forward to re-mount the tensioner, it rotated the crankshaft pulley clockwise by slightly less than two teeth. I made chalk marks on the crank pulley for accuracy. So, I pulled off the old belt, rotated the crankshaft pulley back to TDC, then slightly less than two teeth more (CCW) to my chalk mark. I mounted the new belt, working from top down, securing the belt to the cam pulleys with tie wraps again. There was a lot of belt slack between the cam sprockets w/ teeth engaged, worried me (more later). I fed the new belt downward, tucked in at the idler pulley, and it slid right onto the crankshaft pulley, no resistance. Working back up top, pulled forward on the belt back side to make space for re-installing the tensioner pulley. Requires a little wiggling to thread the bolt. Very helpful at this point to have your wife aiming two flashlights down so you can see the bolt hole. It's a little bit of struggle, but this method had the new belt mounted in about 30 minutes. I took a Craftsman magnetic Apex driver, sawed half the handle off, & made an almost perfect tool for slipping the tensioner spring back on the pin, with the expert help of my flashlight holder. We did the two rotations, & all timing marks were in perfect alignment. After 6 more rotations, to let the tensioner settle in, I torqued the tensioner bolt. And, the slop at the top (between cam sprockets) was gone. Three days later, with all the other parts re-installed, we fired it up. With the ECU un-powered for three months, it took a few minutes to un-scramble itself, eventually settled down to a smooth idle. For those who have struggled & cussed & almost given up on the timing belt R2, this worked for me.
After I replaced the cam oil seals, crankshaft front oil seal, water pump, idler roller, belt tensioner assembly & spring, I set about fitting the new timing belt, using a Mazda OEM (Gates USA) timing belt. I also had a Conti-Tech belt which came in my TBK, but just felt more comfortable using a Mazda part-numbered belt. Hopefully, it will hold up as well as the original Japanese belt did. So, the Mazda shop manual suggests to start the belt at the bottom, route the belt to the right, tucking the belt inside the idler roller, wrap around the exhaust cam sprocket, then up & over the intake cam sprocket. Of course, making sure the belt is tucked in at the tensioner roller, and the tensioner is giving the belt maximum slack (spring disconnected at the pin). There wasn't any way in hell that new timing belt was going to mount that way. It seemed like the belt was about an inch short. I kept that belt over the back of my computer desk chair for about two weeks to warm up & stretch (if they actually do). I made five or six attempts at mounting the new belt this way, and then tried about five more times going from the top down, securing the belt to the cam sprockets with tie wraps & going down through the rollers. Still no joy, the belt would have to be pried on at the crankshaft pulley. That method is a no-go. Gates USA website has training videos that emphasize belts can not be pried on with tools, it over-stresses the Kevlar & Rayon fibers that give modern belts their durability. After these attempts, I took a break for about two weeks. One day I had an idea : with the tensioner pulley removed, could I mount the belt ? Could I create enough slack in the back side of the belt to bolt the tensioner pulley back on, & how the heck would I re-hook the spring ? Should have mentioned earlier that I locked the cams in place right after removing the camshaft cover, using two 8" Crescent wrenches pinched together with a C-clamp. This method locked the cams solid. The old belt mounted on easily, and when I pulled the back side of the belt forward to re-mount the tensioner, it rotated the crankshaft pulley clockwise by slightly less than two teeth. I made chalk marks on the crank pulley for accuracy. So, I pulled off the old belt, rotated the crankshaft pulley back to TDC, then slightly less than two teeth more (CCW) to my chalk mark. I mounted the new belt, working from top down, securing the belt to the cam pulleys with tie wraps again. There was a lot of belt slack between the cam sprockets w/ teeth engaged, worried me (more later). I fed the new belt downward, tucked in at the idler pulley, and it slid right onto the crankshaft pulley, no resistance. Working back up top, pulled forward on the belt back side to make space for re-installing the tensioner pulley. Requires a little wiggling to thread the bolt. Very helpful at this point to have your wife aiming two flashlights down so you can see the bolt hole. It's a little bit of struggle, but this method had the new belt mounted in about 30 minutes. I took a Craftsman magnetic Apex driver, sawed half the handle off, & made an almost perfect tool for slipping the tensioner spring back on the pin, with the expert help of my flashlight holder. We did the two rotations, & all timing marks were in perfect alignment. After 6 more rotations, to let the tensioner settle in, I torqued the tensioner bolt. And, the slop at the top (between cam sprockets) was gone. Three days later, with all the other parts re-installed, we fired it up. With the ECU un-powered for three months, it took a few minutes to un-scramble itself, eventually settled down to a smooth idle. For those who have struggled & cussed & almost given up on the timing belt R2, this worked for me.
