thealleyboy Posted May 21, 2011 Share Posted May 21, 2011 Hey Guys: I'm doing my first new gen timing belt on my 97 Imreza. I've researced the procedure, and think I understand the process reasonably well. I've tried to install the belt twice, and both times the marks came out of alignment. I'm guessing the belt must have jumped, but I cant verify that. I've seen conflicting comments about whether this motor is interference, and I'm concerned that it may have been damaged during the changeover process. I tried to keep everything in line when removing the sprockets but this was impossible. The car ran perfect before changing the belt. I only took it off to do the oil seals. Can anyone tell me definitievely whether the 97 is interference, and is it possible that turning the sprokets during reassembly damage anything? thanks, John Quote Link to comment Share on other sites More sharing options...
idosubaru Posted May 21, 2011 Share Posted May 21, 2011 1997 is interference. what symptoms are you having? are you positive you used the correct alignment marks? some folks use the wrong crank marks. if you install the belt and all the marks are lined up, then it should be fine. if you turn the motor over once - the marks on the *belt* will no longer line up, they don't "stay" in alignment, they're only references for installing the belt and mean nothing after that - because each revolution the belt marks "move" in relation to the crank and cam marks. just saying - don't get confused if the belt marks don't stay in alignment. Quote Link to comment Share on other sites More sharing options...
thealleyboy Posted May 21, 2011 Author Share Posted May 21, 2011 Hey Gary: Yes, I came to that conclusion after going thru the procedure fotr the third time. I watched the belt as I rotated it with a wrench and it definitely did not "jump". I had mistakely thought that the reference marks would come back into alignment after one or more revolutions , and I can now see that it doesnt work that way!! As far as the interference, the engine did run without a belt. The only movement was when I was rotating the sprockets taking them off and reinstalling. Very minimal, but I couldn't keep them completely locked down. Now with the belt back on, it is turning smoothly, and I can feel it building compression. Hopefully, I didn't screw anything up while working on it, but I don't see how it would be possible not to rotate the sprockets at all. I'll go ahead and put it back together and see what happens... thanks, John Quote Link to comment Share on other sites More sharing options...
Fairtax4me Posted May 22, 2011 Share Posted May 22, 2011 Using Zip ties can help hold the belt on the sprockets while you are trying to get everything set. Once the sprockets are set to the proper marks, I hang the belt, zip tie it to the passenger cam. Then rotate the cam by hand a little to give some slack while I set the belt on the crank. Turn it back to take the slack out, adjust if the mark doesn't line up. Then I set a wrench across the top of the crank sprocket, between the belt and the crank sensor. This holds the belt in place so I have two free hands to set the belt on the drivers side cam. A 17mm wrench, or socket on a breaker bar to turn the drivers side cam just a little bit clockwise away from the timing mark, pull the slack out of the belt and set it on the sprocket, turn it back to the mark or until the belt has no more slack. Adjust if necessary. Hold the belt taught by hand and move the tensioner bearing into place. Once the bearing is there the weight of it will keep the belt in place, move the wrenches out of the way and bolt on the bearing. Quote Link to comment Share on other sites More sharing options...
The Dude Posted May 22, 2011 Share Posted May 22, 2011 I'll be doing my first timing belt change this coming weekend. Someone on one of the other Subaru boards suggested removing the spark plugs before changing the belt. The motor can then be rotated by hand. In theory, even the tiniest bit of valve/piston contact should be felt before any damage is done. Rotate the engine by hand a number of times without any valve/piston contact, and you should be safe to go. Hopefully, this will reduce the pucker factor the first time you crank the starter after a belt change. For my first timing belt change, time for completion is not a consideration. Since I have a Forester, I'm removing the radiator, as well. Quote Link to comment Share on other sites More sharing options...
johnceggleston Posted May 22, 2011 Share Posted May 22, 2011 when doing the timing belt on a SOHC ej22, if the crank is in the correct position all the pistons are at mid stroke / mid way between the top and bottom. so with the belt OFF, so you can rotate the cams as much as you want with no interference. how ever it is good to note that turning the crank 90 degrees will bring 2 pistons to the top of the cylinder, and an interference point. so as long as the crank is within about 45? degrees of the correct mark i would think you are ok even if the belt jumps a few teeth. but when doing the timing belt, set the crank to the correct timing mark and then remove the belt. don't move the crank much, or at all, until the belt is back on and you will be good. Quote Link to comment Share on other sites More sharing options...
thealleyboy Posted May 24, 2011 Author Share Posted May 24, 2011 Appreciate all the comments guys.. The car started right up, just as before, so (apparently) , the rotations I did by hand didn't cause any valve damage. The belt was a little noisy as it stretched into place, but it seems to be seating normally. One tidbit hint I'll pass on (haven't seen mentioned yet) is that the belt can be installed fairly easily by doing the two lower rollers in tandem. If the top side is lined up, the belt can be pulled out at the bottom to give you more "play", as the belt is slipped over the idlers. The left idler can be bolted in place first, with the belt spines partially mated to the gear. Then the right idler can be started with the smooth surface of the belt in place. Once it is started and the two idler partially threaded, the bellt can be tapped into place with a soft-faced mallet. I found this the easiest method to keep the three timing marks in alignment without a helper. thanks again for sharing your thoughts... John Quote Link to comment Share on other sites More sharing options...
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