JEEZ...at 13 years you were on "borrowed time"!!!
Problem with VW garages is....it's an OLD van, so they put the apprentice on the job!
Timing is VERY critical on these engines.....should be 55 (the magic number).

I'd go back to the garage, timing details in hand, and see if there is a guy over 50 years old who can check it.
I bet it wasn't even up to temp when the work was "completed".

Yeah, too far advanced, it will start well, but sound like a Massey-Ferguson tractor!

 

Hi

Thanks for that - every article I find on timing problems starts with the premise that it's likely to be retarded and assumes there's problems 'starting' in the first place. We're the opposite. The issue we have is we are in NW Spain, and we specifically used this place in Vigo because it specialized in cars AND vans. You are right though the mechanic was about 25 years old.

I didn't want to attempt the job myself as I'd be stuffed if I got into difficulty - it's not like the UK where you can easily get a mobile mechanic. Here you really have no idea what qualifications and experience these guys have. This was supposed to be a 'confidence baseline' so next time I would know I didn't have 10 years of corrosion to deal with.

I'm sure the garage had problems with the timing and put the old belt back on just to get us out of the shop as they were over-running due to problems with the previous vehicle. With this attitude we're loathe to get them to fix it especially as they said the belt had just got dirty on the journey home! Might be wrong about the belt but I can check as I'll be taking it off soon anyway.

My biggest concern now is I hope the crankshaft/camshaft timing is sound so I only have to deal with the pump-timing. If it is, then I'm expecting to use a dial-indicator to set the 0.55mm reference point and tweak this with the camshaft-pulley followed by the idler-pulley as I don't expect VCDS to say it's 0.55 dynamically.

Can I also assume that it's unusual for the idler pointer to be so far from the raised ridge casting as there's a limit to how much difference they make?

 

Points on the pulley should be close to the markings....but they tend to "wander" back and forth "a little"....

 

Thank you.

 

That idler pulley pointer should be fairly near the casting line on the head when done correctly imo. It's used for fine tweaking on the pump timing along with the tensioner.
Normally the techs are used to it just being a idler so whack it on anywhere.
Personally I set the timing to 60/65 so it's in range but the higher side slightly advanced to aid starting and power

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Seems to me Shankalanks that you have plenty of knowledge to do it yourself with VCDS and all and, anyway,. you are going to end up doing it yourself .We see it all the time on this forum how clueless garages are on this timing issue .The problem is it takes knowledge and practice and the knowledge is dying out because these motors are getting old after all .As long as you get the cam belt end of things right ,and this is common to all cambelts regardless of make ,then you can fiddle about with the pump either by ear or vcds or dti until you get it right .Wrong pump timing will not do any damage .So have a go .Next belt time I am going to do it myself because I am pretty sure now I know far more than 99% of garages .

 

In answer to original question as to why it still runs "ok" is that the ecu is doing its best to adjust the timing,by using maximum retard on the pump advance mechanism , but it is struggling since it is beyond normal limits .Hence some lack of power and more noise .

 

I would imagine if you put the pointer back to the head casting and re adjust the tensioner you would be somewhere near, only a couple of spanners and Allen key required to do it then check the readings on vcds like you have already.

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Thanks to everyone contributing and apologies for the delay as I'm not getting alerts for some reason.

GtiJ: You've answered my next question for me. I had read that 'a little advanced' is not a bad thing so was going to aim for the timing to be around 60 which I hope also accomodates belt-ageing. Also your suggestion that moving the pointer clockwise to the ref. mark will retard the pump helps me, but I was guessing that to get from 1.04 to 55 is a lot of retardation to do on the fine-tune idler and that I couldn't avoid the more brutal adjustment using the pump/camshaft to start with (?)

Other issue is can I trust that the Cambelt has been put on accurately to start with? I would have to check by setting to TDC (which I haven't done on the beast before and by all accounts can be a PITA), and loosen the camshaft pulley. Thing is, I may want to do this anyway as I'm convinced the pump belt is not new, and that they reused the old one for some reason. But did they mark which way it goes back? ( - and does that really matter on the pump side?).

Bourne: Yes and no. I'm retired in Spain now and getting underneath a 3 ton motor-home is not good for my nerves. Unfortunately we've had such rubbish service from garages here that I do as much as I can myself though I'm no mechanic. The Cambelt-Change was out of scope as I couldn't afford to mess up, plus I don't have the 'special' tools except VCDS, I'm working alone and it was 13 years of potential problems. But as you say, I'll be doing it now and I get to buy some expensive use-once tools.
The engine runs the same when I switch to Basic Settings which is what really surprises me, as I didn't think the ECU could make up that difference. This is why I included Measuring Block 004 in the screenshot as I wasn't sure if it was telling me how much the ECU is compensating? I read somewhere that the Duty Cycle figure should be below 10% but I'm not sure.

Anyway the first thing, which is minimal effort, will be to do as you both suggest and move the idler pointer clockwise, and check the tensioner. At least I'll have an idea of what effect this has on the timing, and it will be good practice for changing the belt when a new one turns up (Contitech this time as I've already paid for a VAG one and I'm not buying another).

Thanks again

 

Well the tools are not all that expensive .You can get the crankshaft holding tool and camshaft locking plate kit for less than thirty quid over here and the dti adapter (10mm thread for tdi)for another thirty from Brickwerks plus dti gauge you probably have and you could sell the stuff at the end of the day.I agree with the old age bit being there myself .Could you get a young assistant to do the monkey business while you do the fiddley bits ?Nice to have such fulsome replies anyway Thanks .

 

Hullo. Well I spent some time playing around with the horror, mainly to familiarize myself and get it to TDC and also try and work out the current pump advance by using a cheapo DTI.

At first everything looked OK, pre-existing Tippex marks got me close to TDC and the pump-pulley mark was clear. I used the DTI to check the pump and it seemed to be set to 0.65mm which surprised me as I was expecting higher. The pretty TDC mark below is now sadly obliterated with Tippex.

I was happy to leave the pump as it was, and so adjusted the tensioner/idler to their 'optimum' positions as suggested and (after doing the safety two turns of the crank) tried to start the engine. Zip, Nada, Zilch. Well the starter worked but no chance of starting. After moving the tensioner/idler back half way towards where they were before I tried again, and the best I got was a starty cough, but no running engine.

Next, as I knew I would be changing the belt at some point soon I thought I'd be best checking the camshaft alignment slot, so I undid the rear cam pullet bolt. Oops, I can see why it's a good idea to lock the pump shaft now! Anyway the pulley and belt have now been taken off and it is still at TDC but this is what I saw:

Ain't no way my locking plate was going in there.

So I'm guessing that the garage (Veloso Official VW Car and Van Service Centre in Vigo - I salute you) have screwed up the timing belt proper and the camshaft is advanced (?) by approx. 1 belt tooth. I assumed they couldn't avoid loosening/slipping the front camshaft pulley but does this mean it's possible to do the job without removing the rocker cover at all. Surely if you remove the rocker cover you would automatically lock the camshaft with the plate?

I have two more questions now which I hope someone can answer:

- Is this directly responsible for the weird timing settings and tensioner/idler positions that prevent the engine from firing when set 'correctly'?

- Do I really have to remove the intercooler, oil-feed, rocker-cover, auxilliary-belt etc etc just to get the camshaft to line up horizontally at TDC. I just don't think I can avoid slipping the front camshaft pulley. I was just hoping there was a short-cut to slipping the belt? Obviously I don't want to go anywhere near the damper pulley.

Any help here would be greatly appreciated. Thanks

 

I know you dont want to but if the garage cant set the pump timing or the cam to crank timing I would have to take it all apart to check everything. Cambelt tension could be out or something could be loose.
It's not worth the risk imo as when the 2.5tdi goes wrong it's very messy! I've rebuilt a few with snapped cams, damaged pistons etc

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What they did was move the the camshaft to get the belt teeth of the cambelt to engage with the cam sprocket .I can just follow the "thought"process !What should happen is that the sprocket is slipped to suit the teeth while the camshaft remains locked in place .They just shoved the belt on, probably without removing the rocker cover at all .There is only one way to do it and that locking groove is not put there without good reason .You must complain loud and long .

 

Hullo, and thanks to you both for your comments,

:GtiJ I know this might be a mistake but I'm desperate to avoid removing the damper-pulley, which presumably means I have to trust that the tension-roller will be OK too. If I can get as far as revealing the cambelt and front camshaft-pulley, then I'll be able to confirm that they actually changed the timing belt, as opposed to putting the old one back wrong. At least this would mean that they probably removed the lower cover and changed the tensioner. Just a shame you can't see the tensioner because of the lower-cover.
It's not that I don't appreciate your advice :GtiJ, which I know is right, but the damper-pulley is really just one step too far in my current 'pi**ed-off' state and I have to believe that that was the absolute minimum that was carried out. They did change the water-pump which I know as I saw the old one in the 'work-area', and I'm sure they would find it a lot easier to tighten up the camshaft bolt to 160nm + 1/2 turn, compared to 58Kg me!

I can see what you mean :bournricha. When I first looked at the engine to check which clips etc had been broken and replaced with tyraps (which I've come to expect), I was suspicious because it didn't look as if they had even removed the inter-cooler - no marks or handprints in the thin layer of dust and oil. This presumably doesn't mean they couldn't get to the front camshaft pulley to put the belt on, but just that they couldn't tap it from the back to allow it to slip.

[It's a waste of time complaining here. What you do is go to the police and threaten to 'denounce' the garage i.e. take them to court. You have to make a case and the local judges decide if it's worth pursuing - sort of small claims. They do it all the time, even between family members. Bizarre. I think it's a throwback to exposing your misdemeanors to the church. Anyway it's expensive and stressful and I still wouldn't trust them. I was talking bad Spanish to a retired local machanic yesterday and he was fixated on the need to do 'before' Tippex' marks so the new belt goes back exactly as the old and the timing should be spot-on, and so I guess they wouldn't even consider slipping the camshaft. I suppose in theory you don't even need to get it to TDC in that case. We used the official VW garage this time because we expected them to do it old-school to justify the inflated prices. My bad!
They did have some lovely tools hanging up though . . . ]

So unless I'm totally off mark I'm guessing the absolute minimum would be for me to:
- expose the cams, rotate the camshaft (via the crankshaft) and insert/centre the rear camshaft locking-plate
- undo the front camshaft-pulley bolt 1.0mm or so (1 turn?) and tap it loose so it can slip (is this possible under tension?)
- rotate the cranks back to TDC
- re-tighten the front camshaft-pulley to 85nm/100nm depending on bolt markings
- remove camshaft locking-plate
- rotate two turns to check all aligned still, and if OK reassemble to the injection-pump timing stage

BTW: the image below shows a date (which I think may be the BBE date) on the pump-timing belt. Somehow I don't think this was new.

Thanks again.

 

Yep ,I think your method of correction is spot on .It should be possible to do with the tension on as it is not very much after all, or the thing would wear out in no time .Cant remember, but I think you can catch sight of the tensioners maybe with a torch ,with the top cover off.Good Luck!

 

Many thanks again.
Just have to be careful to avoid damaging the rocker-cover gasket I guess. I can take my time as motorhome's not going anywhere for a while, Covid permitting.
Ciao

 

Post us your news when you do it

 

Have had another look at your posts Moving that roller indicator clockwise will have had the effect of retarding the pump timing ,because doing so will have pulled the belt in a clockwise direction ,the opposite to the direction of rotation when viewed from that end of the engine .This would have altered the moment of injection sufficiently to prevent starting .When you put it halfway back it did try and if you had put it back to the original ,but wrong, position it would have started .Properly the rollers should be set then you adjust the pump by allowing the pump end cam sprocket to turn .
The out of horizontal locking bar line would not be sufficient to stop it running because the moment of injection is dependent on piston position not valve position .As it is, the valve sequence, is advanced in relation to the piston (crank )position .The exhaust valve on number one will be on the way to opening when the piston is at tdc,when it should be tight shut in preparation for the power stoke .It may be ,as it is (was),that the exhaust valve was opening during the power stroke .If the mismatch were bad enough ,which I dont think it was ,contact would take place .

 

Hiya, I've been looking at this too whilst I've been attempting to correct the problems. All directions and rotations (c/w or anti-c/w) are from the viewpoint of the left of the engine.

If the mismatch were bad enough ,which I dont think it was ,contact would take place .

That's an interesting point because I have no idea just how much latitude there is in cambelt position. It appears they were relying on Tippex marks and got one tooth out - it was evident when I took the 'top-cover' off the cambelt. BTW, I will write up properly the sorts of issues I have been encountering, not least of which is tightening up the rear camshaft pulley to 160nm without damaging the locked pump. I love the way it's a throwaway line to tighten to torque.

Moving that roller indicator clockwise will have had the effect of retarding the pump timing ,because doing so will have pulled the belt in a clockwise direction ,the opposite to the direction of rotation when viewed from that end of the engine .

OK. This is weird as the way I was looking at it was: the Auto-tensioner has a simple but significant 'take up the slack' job. The Rear-Idler however is set at a reference mid-point and because of its eccentric shape has the effect of increasing/decreasing the distance between the rear-camshaft and the pump-pulley when it is rotated away from this ref position. If you rotate it c/w then it bulges into the belt increasing its travel, and conversely anti-c/w of the ref point would reduce the bulge (straighten the belt) thereby shortening the distance.
The camshaft pulley is effectively fixed so the auto-tensioner slack adjustment only has the effect of applying a rotation to the pump-pulley.

So the way I saw it was:
Idler c/w, Pointer to the right of ref, Idler bulge increases (greater belt distance), pump-pulley forced to turn anti-c/w (advance)
OR
Idler anti-c/w, Pointer to the left of ref, Idler bulge decreases (reduced belt distance), pump-pulley free to turn c/w (retard)

Now this would mean that the mechanics had been forced to retard the engine as much as possible to get the engine to run - presumably you can have too much advance - but couldn't get it below 104. Their software would have shown these values, and if they could have retarded the timing by simply moving the pointer c/w to the reference point then they would have. So I'm thinking that when I moved it to the reference point I must have advanced the timing beyond the ability to start at all. This would imply that the tooth error with the belt has a massive impact on the timing. Of course I don't know if they manually adjusted the pump with a DTI to get it to 0.65 or so.

I'll continue with this tomorrow as my laptop sounds like it's about to crash on me. Meanwhile am I losing the plot with this? I've actually done most of the fix. I've just got the inter-cooler to put back with the brake-booster hose which I removed for safety. No idea if it will start, but I also want to check the pump with the DTI to see if final tightening of the rear camshaft pulley (after the pump lock had been removed) affected the timing. 160nm is very difficult in such a limited space. I was thinking once you get to 100nm or so, you could stick the beast in gear with the handbrake on hard, and assuming the cams and belts handle the torque, just let the engine stop the camshaft from turning. Maybe still better with a pulley-holding tool.

Thanks

 

All

I can see that there might be some raised eyebrows over final-tightening of the rear crankshaft bolt after loosening the pump pulley lock.

The logic here is that the pump lock is only needed whilst there's a chance that the pump-tension can cause the camshaft pulley to slip on its taper. Over 75nm or so (I made that up) it simply isn't going to slip with the pent up force in the pump.

So if you unlock the pump now and do the final tightening using just the torque-wrench and counter-hold, if there's any slippage here it should be so small as to be managed by the fine tuning of the idler pulley. That's what it's for. And significantly there's no potential to damage the pump now, which is most important.

Perhaps wrongly, I feel there's a hangup with the idler-pulley being set to its reference mark. There is no difference as far as the engine is concerned between 0.55 timing with the pointer 1 cm to the left of the casting ridge, or 0.55 with the pointer 1 cm to the right. All that has happened is the orientation of the four pulleys involved has rotated round a point mid-way between the tension and idler pulleys.

The other suggestion of using the gears/crankshaft and belts may be a little more suspect . . . .

Ciao - (I'll keep updating this post because I can easily find it for my own reference without using the search function.)

 

Yep ,I think you are right about the rollers and pump position .Takes some getting your head around !160nm is a lot .Holding tool essential .Dont think you should give that sort of torque to the belts though .Think pump must not be locked while torqueing up .The Brickwerks guide suggests rotating and checking with it just nipped up until your are sure you have got it where you want it .Good Luck!

 

160 nm and 180 degrees is possible on the ground as I recently done it myself, i used the lock tool and wedged a metal 3/4 bar against the chassis leg and the tool. Now when it came to the 180 degrees i used white paint on the new crank bolt painted at 12 o clock then used my feet to push my 3/4 inch ratchet and 27mm socket till paint mark was facing the 6 oclock position or 180 degrees. Good luck with it

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Hi MPH76

The 160nm we're referring to is the rear camshaft pulley when the pump-timing belt is being fitted.

I think the cambelt damper pulley is easier in some ways because of the way you described, plus you could also use hydraulic jacks to finish the extra 1/2 turn. I believe mechanics use the paint-mark method with an air-impact-wrench.

Cheers

 

Oh yeah sorry I misunderstood, I use a torque wrench and the counter hold tool, I don't use an air impact gun. But hell yeah these engines need to be done correctly, I brought my T4 with a loose crankshaft pulley and I suspected it was down to a poor quality timing and injection belt replacement. The camshaft was snapped in 4 places, and the crankshaft gear keyway was rounded off.On reading the invoices that came with my van I discovered it had a new timing belt and injection pump belt 1500 miles ago, I also found the injection belt was way too slack. Any engine with an odd number of cylinders relies on balance, my theory is that the injection belt tensioner was fitted incorrectly and this slack in the belt caused resonance that transfered through the camshaft and caused the crankshaft keyway damage. There was tip ex marks on all the pulleys and the rocker cover was in my opinion never removed during the timing belt replacement. Second photo here is off the slack in the injection belt that i found. Also the tensioner as mentioned here in this post was not in the correct position but was tight.

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Howdy

OK, short one this time as I need to replace the tensioner on the pump side as the locating tab has bent. I think I may have unscrewed the 13mm bolt a bit too much which allowed the tab to pivot out of the locating slot. Not knowing this had happened meant that tightening the bolt then distorted the tab enough to make it unpredictable. Of course I could blame the VW garage instead. Oh well, just learning-curve stuff - have to be more careful next time I think.

This happened after first start of the engine, when VagCom showed an avg. advance of 0.70 despite me explicitely setting the DTI to 0.55mm lift. I'm not quite sure why the dynamic reading (warmed engine, basic settings etc etc) was significantly different, though I found I could lower it using the rear idler. Anyway, for fun and practice, I decided to redo the pump timing from scratch which is when the tensioner decided to damage itself. Engine took a while to start the first time which I guess was loss of diesel in the fuel lines.

So question is, is the timing discrepancy caused by:
Poor technique (very possibly)
Duff DTI, well I checked my cheapo DTI against a Mitutoyo model and there wasn't enough difference for this job (so no)
Slight movement of the tensioner body in the slot under load, coupled with belt-flex under load (maybe)

So this raises the question about the accuracy of DTI setup without dynamic s/w follow-up. Anyway in contrast to what I said in an earlier post, I now expect to go a**l and once I have the idler and tensioner in their reference positions and stable, then I am likely to do any timing adjustments >5 by slipping the belt on the cam (aiming to get 55-60 as the 'cloud range'). Ultimately I will be comfortable so long as the absolute maximum stays in the low 60s.

Won't be able to do anything for three weeks or so now but not a problem. Also pleased that I finally managed to find the obscure 'service position for the long-nose version', NOT the short-nose version which has about 100 YouTube videos.

Just to add a useful picture, I found that an o-ring at the base of the DTI adaptor made it more secure on the pump, and also allowed it to be rotated so I could get the Allen key in the grub-screw.

Ciao

 

Most people say forget the dti use vcds, they also mostly say don't set it to 0.55 lift set it to 0.70 unless it's a brand new engine, some people even say advance it as much as possible till it smokes and then retard it a bit. So when i done mine I set mine with the dti to bang on 0.55, with the thought it must be the best base setting. I found it started immediately and there was no smoke and no diesel rattle. So I stayed with that and never bothered with the vcds. I think the vcds reading is a compensated reading.

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Think that's going off topic and deserves a discussion of its own (which probably already exists on this forum).

Alternatively I'm sure there are many opinions about DTI vs VagCom vs VAG1552 on the RossTech forum, but I have to admit I am not brave enough to diss VCDS.

All I can say for sure is the generation of a 'cloud' of timing marks suggests timing is not an exact science and 0.55mm lift does not directly translate into a precise injection point. The ECU is one of a number of variables, including injector/sensor condition for example, that impact on engine running. The DTI preset is as much about allowing the engine to start, so that you can subsequently tweek the system until you are happy, and any compromises you make are your choice. I, for example, will choose a cloud between 55-60 because I live in Spain and want to keep engine temperatures lower.

à chacun son goût , as they say.