JST Posted November 16, 2009 Share Posted November 16, 2009 i have a problem in that the timing belt slides towards the front of the vehicle and rubs on the bottom crank pulley shoulders and is slowly shredding the belt. I replaced the idler and tensioner when i changed the belt with like for like. that is to say the smooth no shoulder metal ones. i was informed these were the latest ones to fit. The crank pulley has shoulders on it. none of the other pulleys do. i understood that the early ones had a shoulder on the tensioner and no shoulder on the crank. Anyone know which is correct? Is there anything that should go behind the idler or tensioner - crush 'zone', washer or similar that i should be fitting? at the moment they asre fitted flush to the rear timing housing. Would there be anything wrong with fitting both a tensioner with shoulders and running that into a bottom crank with shoulders? obviously with the corresponding correct idler as i believe these are different too but am not sure of the differences. Quote Link to comment Share on other sites More sharing options...
rusty_wingnut Posted November 16, 2009 Share Posted November 16, 2009 if the belt is torqued too tightly it will run towards the front edge.... Quote Link to comment Share on other sites More sharing options...
zoltan Posted November 16, 2009 Share Posted November 16, 2009 Is this for your TGV? Looking at you photos the pulleys look as though they are stamped out and formed from steel as a pressing. I wonder if the teeth are running parallel to the cam/crank axis. It only needs to be out by a few thou for the belt to creep. It will run up against the keeper and the wear begins. A properly machined steel pulley with the teeth gear cut would at least remove this from the list of possible problems. If the pump is not seated properly or the cam was line bored off these would also encourage the belt to track off. Quote Link to comment Share on other sites More sharing options...
JST Posted November 16, 2009 Author Share Posted November 16, 2009 yes it is for the TGV, dont all the 300s have the same pressed steel pulleys? The last belt when i took it off had worn through on the rear - the tensioner bearings were shot so the belt was too loose there RWN assessment of bring too tight could be the case. the belt was tensioned correctly with a deflection torque wrench. Quote Link to comment Share on other sites More sharing options...
Les Henson Posted November 16, 2009 Share Posted November 16, 2009 Early ones had the shoulder on the tensioner, but as drive to the belt is provided by the crank sprocket, then it's somewhat too late to centre the belt after it's run round everything else. The shouldered crank sprocket is best as alignment over everything else is done at what's really the start point. Genuine crank sprockets have a spot welded shoulder on the sprocket, which is known for coming loose and causing damage to both the belt and the timing cover. Bearmach supply a one-piece crank sprocket (the shoulder can't come detached). It's quite normal to find some rubber fibres in the timing chest of a vehicle that is close to or at the change interval period. Just about all other makes of vehicle use the crank sprocket to set the belt alignment. If it runs off track, then a driven wheel (cam, Inj pump, water pump, for example - will be at fault) Tensioners and idlers don't tend to push a belt off track unless they are faulty - the back of the belt runs on them, so there's little influence on the alignment of the belt itself. Les. Quote Link to comment Share on other sites More sharing options...
JST Posted November 16, 2009 Author Share Posted November 16, 2009 cheers Les, so its pointless running the idler with shoulders then from what you say which makes sense. maybe she was just on too tight anyway. waiting for a new belt currently. Is the tensioner bolt on the latest ones (a screw cap) a stretch bolt or not? ie can it be reused? Quote Link to comment Share on other sites More sharing options...
Les Henson Posted November 16, 2009 Share Posted November 16, 2009 Just to add - if (for instance), one of the sprockets was 2mm out of line with the others, then it would only take 2mm off the 25mm width of the belt. For continuous reduction of the belt width through wear - one of the sprockets (or a faulty idler/tensioner), would have to exert a continuous pressure on the belt to move it sideways. A worn idler or tensioner bearing, would most likely cause the wheel to sit at an angle, so the belt would be forever being pushed outwards. This would inevitably cause the belt to reduce in width and eventually break (or become a bit of black string). Just my thoughts on this - bit too deep for my brain Les. Quote Link to comment Share on other sites More sharing options...
JST Posted November 16, 2009 Author Share Posted November 16, 2009 Just to add - if (for instance), one of the sprockets was 2mm out of line with the others, then it would only take 2mm off the 25mm width of the belt. For continuous reduction of the belt width through wear - one of the sprockets (or a faulty idler/tensioner), would have to exert a continuous pressure on the belt to move it sideways. A worn idler or tensioner bearing, would most likely cause the wheel to sit at an angle, so the belt would be forever being pushed outwards. This would inevitably cause the belt to reduce in width and eventually break (or become a bit of black string). Just my thoughts on this - bit too deep for my brain Les. idler and tensioner were both replaced. Quote Link to comment Share on other sites More sharing options...
zoltan Posted November 16, 2009 Share Posted November 16, 2009 yes it is for the TGV, dont all the 300s have the same pressed steel pulleys? I'm not familiar with the innards of these. I do quite a lot with timing belt drives at work including cutting pulleys so I look on a pressed steel pulley as being a design suggestion made by the accountant as opposed to the engine designers choice Quote Link to comment Share on other sites More sharing options...
Phil Hancock Posted November 16, 2009 Share Posted November 16, 2009 Yup the change from solid to stamped tin pulleys had got to be an accountants influence. Quote Link to comment Share on other sites More sharing options...
will_warne Posted November 16, 2009 Share Posted November 16, 2009 James, I have been led to believe that the TGV uses a differant belt with a differant tooth profile. If you've used 300 tdi parts I'd keep a very close eye on things..... Quote Link to comment Share on other sites More sharing options...
zoltan Posted November 16, 2009 Share Posted November 16, 2009 Are both the 300 TDi and the TGV using the same pressed steel pulleys? Does anyone make proper pulleys? Quote Link to comment Share on other sites More sharing options...
Les Henson Posted November 16, 2009 Share Posted November 16, 2009 Tensioner centre should be stud and shouldered nut, idler should be Allen bolt. If both the crank sprocket and and tensioner wheels have shoulders, then there's a potential conflict unless both are inline with each other. One shoulder, and everything else to follow it is the safest way to go. Conflict of alignment of the timing belt will only make matters worse/more difficult to resolve. Les. Quote Link to comment Share on other sites More sharing options...
cipx2 Posted November 16, 2009 Share Posted November 16, 2009 JST, my understanding from your message is that you had this timing belt issue sliding forward both before and after changing the timing belt bits. The HS 2.8 came with smooth idler+tensioner and shouldered crank sprocket from start so I wouldn't worry to change from that in the 1st place. I'm with Les' oppinion, a don't think shouldered tensioner would help. The belt is the same (same teeth profile and everything) as for the 300 tdi and the 2.5 Maxion. For example, Goodyear sells this belt as an aftermarket part for all 3 engines, see http://imperio4x4.com.br/manuais/ponto_distrib_diesel_maxion.pdf Like been said, an over tensioned cam belt can have this effect. Make sure you tension the plate at 9-10 Nm. Did you check for existence and/or replace the o-ring behind the crank pulley? Possibly the crank pulley is too far in? If all fitted ok, what I would try to do is to fit the camshaft pulley in place of the inj pump pulley and viceversa. To do that you'll have to turn each pulley the other way round(check the inj pump pulley has the timing mark on the other side, just to be sure, and fit it accordingly). This could have one the following effects: - the belt runs right - you're lucky - nothing changes - the pulleys are not at fault which means could be something like on the very early 300tdi when LR corrected the inj pump position by fitting a different bracket (or something like that) - the belt slides backward and rubs against rear crack pulley shoulder - something wrong with one/both of the pulleys - replace them. Quote Link to comment Share on other sites More sharing options...
Les Henson Posted November 16, 2009 Share Posted November 16, 2009 I think the inj pump and cam sprockets are uniform - regardless of which way round they are? If the two sprockets have a timing mark on them (reversed on the cam), then doesn't that in itself indicate that they are identical in any position? Les. Quote Link to comment Share on other sites More sharing options...
cipx2 Posted November 16, 2009 Share Posted November 16, 2009 They should be uniform in theory but I'm considering a manufacturing fault on one of them. The pulleys are identical, also in theory. Quote Link to comment Share on other sites More sharing options...
JST Posted November 16, 2009 Author Share Posted November 16, 2009 cheers for all the input and points to consider so far guys; James, I have been led to believe that the TGV uses a differant belt with a differant tooth profile. If you've used 300 tdi parts I'd keep a very close eye on things..... Belt came from M&D as they told me it was different to the 300 one but looking below this appears not to be the case. When i gave the nos off the M&D belt to a supplier today they came back and said thats a 300tdi belt! JST, my understanding from your message is that you had this timing belt issue sliding forward both before and after changing the timing belt bits. The HS 2.8 came with smooth idler+tensioner and shouldered crank sprocket from start so I wouldn't worry to change from that in the 1st place. I'm with Les' oppinion, a don't think shouldered tensioner would help. The belt is the same (same teeth profile and everything) as for the 300 tdi and the 2.5 Maxion. For example, Goodyear sells this belt as an aftermarket part for all 3 engines, see http://imperio4x4.com.br/manuais/ponto_distrib_diesel_maxion.pdf Like been said, an over tensioned cam belt can have this effect. Make sure you tension the plate at 9-10 Nm. Did you check for existence and/or replace the o-ring behind the crank pulley? Possibly the crank pulley is too far in? If all fitted ok, what I would try to do is to fit the camshaft pulley in place of the inj pump pulley and viceversa. To do that you'll have to turn each pulley the other way round(check the inj pump pulley has the timing mark on the other side, just to be sure, and fit it accordingly). This could have one the following effects: - the belt runs right - you're lucky - nothing changes - the pulleys are not at fault which means could be something like on the very early 300tdi when LR corrected the inj pump position by fitting a different bracket (or something like that) - the belt slides backward and rubs against rear crack pulley shoulder - something wrong with one/both of the pulleys - replace them. Hi Cipx2, the old belt that came off had worn at the rear! the new one is rubbing at the front! Crank pulley O ring hasnt been touched and i believe the pulley is on in the correct position. the inner side of the shoulder lines up with the tensioner face too. I will run with the smooth idler and tensioners as suggested - thank you for knowing how the TGV was built. will get another belt and see how that ones goes Quote Link to comment Share on other sites More sharing options...
Mo Murphy Posted November 16, 2009 Share Posted November 16, 2009 Perhaps the crankshaft is bent James ..... Quote Link to comment Share on other sites More sharing options...
Les Henson Posted November 16, 2009 Share Posted November 16, 2009 That's possible/likely Les. Quote Link to comment Share on other sites More sharing options...
zoltan Posted November 16, 2009 Share Posted November 16, 2009 Would a bent crank nose not show its hand with noticeable vibration? It would also cancel the belt tracking every half crank rotation My money is still on those nasty pulleys Quote Link to comment Share on other sites More sharing options...
cipx2 Posted November 17, 2009 Share Posted November 17, 2009 ...... Hi Cipx2, the old belt that came off had worn at the rear! the new one is rubbing at the front! .. A slight touch/rubbing is not that much of a problem. That's why the shoulder are there, to provide a bit of belt guiding. The shavings you found in the timing chest could have been produced by something else but the crack pulley shoulders. The shavings could have been the result of tensioner/idler bearings being shot and the belt being loose. I would use the belt everybody uses for the 300tdi, put all back by the book and keep an eye on the belt for a while looking for shavings etc. Quote Link to comment Share on other sites More sharing options...
JST Posted November 17, 2009 Author Share Posted November 17, 2009 A slight touch/rubbing is not that much of a problem. That's why the shoulder are there, to provide a bit of belt guiding. The shavings you found in the timing chest could have been produced by something else but the crack pulley shoulders. The shavings could have been the result of tensioner/idler bearings being shot and the belt being loose. I would use the belt everybody uses for the 300tdi, put all back by the book and keep an eye on the belt for a while looking for shavings etc. new std 300 belt coming today its not shavings that are coming off, more like 1mm of belt worn through in 10mile route. canvas loops are showing! the only thing i can think is that she was too tight. Quote Link to comment Share on other sites More sharing options...
JST Posted November 18, 2009 Author Share Posted November 18, 2009 new belt arrived yesterday - think i have found the problem, the new belt is a tdi one and measures 30mm across the old one was closer to 33mm hence the rubbing! the old one was stated 30mm as well. something i hadnt thought to check prior to fitting and it looked/felt fine on the bottom shouldered crank when fitting. Quote Link to comment Share on other sites More sharing options...
JST Posted November 19, 2009 Author Share Posted November 19, 2009 belt coming off the pulleys is sorted but i cant sort the timing issue now! Quote Link to comment Share on other sites More sharing options...
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