Digger19 Posted January 20, 2007 Share Posted January 20, 2007 With #1 cylinder at TDC where are the other cylinders relative to TDC irrespective of what stroke they may be on. Reason I am asking is I just changed my timing belt. While trying to break the crank pulley slipped three teeth on the crank gear. After I finally got the pulley off the driver side cams came off the lobes and slipped from their timing marks. Rotated 120 degrees for the top cam. Don't remember how much the bottom rotated when it came off the cam lobes. Put the engine back together last Sunday, started fine and ran fine. Today, I was outside the car with the engine running(for the first time since) and I hear a noticable knocking. Decreases in volume with RPM increase but still there none the less. Coming from the drivers side of the engine. At times I think it is from the #2 cylinder area, and at other times I think it is from the timing cover area. Really hard to tell. The knock is quite loud. It is not erratic but is. In other words it is not like every second or every half second , but is more like 6 or seven knocks rapidly one after the other, then nothing for a few seconds, then the pattern repeats. My thinking is I may have bent a valve when the cams slipped from their timing marks as their is quite the push by the lifters/springs when the cams slip off the top of the lobes. I would think though that a bent valve would have a more consistent knock though. I am going to take the timing covers off tomorrow morning, check things over and see if the noise goes away. Any other ideas?? Quote Link to comment Share on other sites More sharing options...
hohieu Posted January 20, 2007 Share Posted January 20, 2007 Is it piston slap? Quote Link to comment Share on other sites More sharing options...
porcupine73 Posted January 20, 2007 Share Posted January 20, 2007 Do you have the dohc or the sohc? Quote Link to comment Share on other sites More sharing options...
Digger19 Posted January 20, 2007 Author Share Posted January 20, 2007 How loud does piston slap get? Can't hear this at all from inside the car, but man is it loud outside. Sounds like a clunky old deisel rattling away. This would be the best way to describe it. The noise though isolated to what I think is #2 cylinder. Because I cant hear it from inside the car this may have been going on for longer than I thought, but then again maybe not. DOHC. Took the timing covers off and all accessory belts this morning. Knock is more rhythmic than I thought with engine cold. When I was listening last night I had just driven the car for about 10K and that may account for the more sparatic sound. Quote Link to comment Share on other sites More sharing options...
johnceggleston Posted January 20, 2007 Share Posted January 20, 2007 check this out it may help diagnois. http://remanufactured-engines.com/page4.htm john Quote Link to comment Share on other sites More sharing options...
Tech1967 Posted January 20, 2007 Share Posted January 20, 2007 With the DOHC there is a warning in the factory manuals not to let the cams rotate a certain direction in relation to each other or the valves will hit each other. I've had them slip a few times but as luck would have it they always seem to go the right direction. #2/timing cover area tapping noise is possibly your tensioner. Almost all the tensioners that come through my dealership are the one piece units. If that's what you have then they are horrible for the tensioner body knocking on the block* (in the interest of simplicity). Inspect the tensioner where the shaft comes through the seal. You are looking for leakage past the seal and contact on the back edge of the bore. check this pic: http://www.vanbran.com/bug/images/conversion1/tb-tensioner1_l.jpg The black mark at the back is where it's been hitting and that will knock! Subaru asks dealer techs to rule this out before doing repairs for piston slap. A little side note here. There have been one or two that I forgot to put the pin in before disassembly. I pushed the pin back slowly in the vise as per destructions and reinstalled them since they seemed ok when they came in and passed physical inspection. They knocked after leading me to suspect that they don't appreciate being fully extended in their middle age. Good luck. Quote Link to comment Share on other sites More sharing options...
Digger19 Posted January 21, 2007 Author Share Posted January 21, 2007 My suspicion is that #2 was not near TDC if #1 is. #3 or #4 maybe, and that is why i asked about the piston position. Can't quite see all of your tensioner, but it looks different than mine. Mine has two bolts holding attaching it to the blockand I know that on later models they went to 1 bolt tensioners. Having said all that, the noise disappears totally more or less when the engine is warm. The reason I say more or less, is after driving it for 10 minutes yesterday, idling away it disappeared as fast as it appeared. Later in the day, the noise was there as soon as I started the car. Drove for a couple of blocks, the noise disappeared. Arrived at my destination about 5 minutes later and it was there sporatically but regularily. Drove home three hours later, it was there on start, disappeared quickly and was not there when I arrived home. It is quite loud as I hear it inside the car no problem at all. Sounds like someone is taking a hammer to the head of the piston if I could describe it, or the diesel clanking but more rhythmic is also an adequate description. Can piston slap be this loud or have this type of sound? Do these engines have any history of lifters leaking down? If so could this cause the sound I am describing? For the last 5 or six months I had beeen noticing when I started the car up in the morning a ticking sound, much like maladjusted or bad lifters. Went away after a few minutes. Could it progress to this type of noise this fast? Quote Link to comment Share on other sites More sharing options...
usaru Posted January 21, 2007 Share Posted January 21, 2007 "...they don't appreciate being fully extended in their middle age." Yes, don't we all, especially when it comes to "knocking". Quote Link to comment Share on other sites More sharing options...
skibumm100 Posted January 22, 2007 Share Posted January 22, 2007 Do these engines have any history of lifters leaking down? If so could this cause the sound I am describing? If it's like mine (a '98), it doesn't have hydraulic lifters. It's DOHC with buckets and shims.....no hydraulic lifters. Quote Link to comment Share on other sites More sharing options...
Tech1967 Posted January 22, 2007 Share Posted January 22, 2007 Part of the procedure for diagnosing piston slap as per the bulletin is to pull the #4 (drivers rear) injector connector and see if the noise goes away. And in answer to the question I think you might be asking - when you are all lined up to change the belt all 4 pistons are halfway down the bore. Quote Link to comment Share on other sites More sharing options...
Skip Posted January 22, 2007 Share Posted January 22, 2007 "With #1 cylinder at TDC where are the other cylinders relative to TDC irrespective of what stroke they may be on?" And in answer to the question I think you might be asking - when you are all lined up to change the belt all 4 pistons are halfway down the bore. Two different positions mabye this will help the orig question Thanks to McBrat and the USRM Quote Link to comment Share on other sites More sharing options...
Tech1967 Posted January 22, 2007 Share Posted January 22, 2007 When you're set up to do the timing belt though and the cams get away on you they aren't going to hit the pistons because they're all halfway down. The valves can hit each other if the cams go the wrong way when they spin. The timing marks were all lined up properly right? Single line up on the intake cams and mark on t-belt crank pulley straight up to the mark on the crank sensor mount. Quote Link to comment Share on other sites More sharing options...
Skip Posted January 22, 2007 Share Posted January 22, 2007 When you're set up to do the timing belt though and the cams get away on you they aren't going to hit the pistons because they're all halfway down. Just a side note - this is also true of the EA82 series. The valves can hit each other if the cams go the wrong way when they spin. Now THAT is a very good thing to know!! Thanks Tech Quote Link to comment Share on other sites More sharing options...
Digger19 Posted January 22, 2007 Author Share Posted January 22, 2007 Thanks for all the help: Both cams rotated clockwise looking from the front of the engine. As I read more and listen to the engine, I am leaning toward a faulty/tired tensioner. What drives me there is the history of the component( at least from what I read) and the consistent yet inconsistent knock. As I would now think that I damaged nothing else during the replacing of the belt, sounds like the logical place to go next. Quote Link to comment Share on other sites More sharing options...
Tech1967 Posted January 22, 2007 Share Posted January 22, 2007 The tensioner style you describe can be a pain to adjust if you've never seen one. I'm a dealer tech and since I've only seen one of them come through here and I'm picky I had the damn thing apart 3 times before I was happy (just the timing gear, not the whole job). I found it best to adjust the tension first then get the cams where I wanted them. Get the cams in roughly the right spot and snug up the adjuster till you can just get the bottom left (looking from front of car) idler and the toothed idler off and on with the pin in the tensioner. Take those two idlers off and set the final cam position (if they are out a tooth) then reinstall the idlers and pull the pin. Spin the whole deal around once and make sure your marks still line up. I would have known that but only entered the dealership enviroment 4-5 years ago. Found the warning too. If the drivers side intake cam spins counterclockwise while the exhaust cam (bottom) spins clockwise then you probably have a disaster on your hands. Quote Link to comment Share on other sites More sharing options...
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