Cambelt change time, brave the DIY?! :) Couple of Questions

[jimbof]

So, I figure I've got the tools and enthusiasm (will buy the locking tool for the change), and I quite like the idea of doing this myself as the car has got over 150K on it now, I'd like to cross cambelt change off the bucket list...

 

Understand why we don't want locked in toque - hence loosening the 3x bolts on the sprocket before tensioning - but I don't understand how the timing isn't off afterwards as it looks like (from videos) there is quite a lot of adjustment either way on those bolts.  Also my concern (as a rookie) is that can the amount of movement result in refitting the belt "a tooth out"?

 

In ERWIN I see them using a counterhold while tightening the camshaft sprocket again - is this to set the timing correctly?  The SKF video doesn't show any counterhold being used:

 

And then the thorny question of the studs.  I can't see any guide anywhere on how to remove / refit these - anyone got a link to the info? 

 

 

[fordfan]

When you slacken the 3 bolts on the cam pulley you are only moving the pulley and not the camshaft so you can't get it a tooth out, the only thing that can happen is that the cam pulley ends up in a position where there is no adjustment left in one direction, hence setting it in the middle.  To remove the stud you can use the lock nut method, screw a nut onto the stud and then screw on another one, lock the two nuts together by tightening them onto each other and use a spanner on the lower one to unscrew the stud, set up the new stud in the same way and screw it in using the top nut.

 

The counterhold on the cam pulley is used so that you don't put undue force on it  when undoing/refitting its fixings, the timing pin should be capable of withstanding 3X25nm.

 

It's important to observe the tightening torques, especially on the tensioner.

 

The timing is kept by accurate fitting of the locking tools, once they are fitted the timing is locked.

[jimbof]

Thanks for the info, much appreciated.  

 

So when you hear of people getting it "a tooth out", they must be marking and praying?

 

The bit I don't get is that by my understanding the timing is controlled by the position of the cam pulley relative to the sprocket; changing this relationship changes the timing.

http://www.myturbodiesel.com/wiki/camshaft-timing-torsion-value-adjustment-on-vw-and-audi-pd-tdi-engines/

 

 

I can't see how this relationship is controlled by the process - once the sprocket is free to move, surely it can end up in not quite the right position once tensioned, and then need adjusting?  Or am I missing something? 

[0wl]

Apologies if I'm stating the obvious or repeating what you were saying, but the timing is controlled by the relationship of the crankshaft sprocket with the camshaft pulley. The article you linked to is about tweaking the timing and doesn't involve releasing the tension on the belt, it just lets you fine tune the position of the cam in relation to the crank by freeing the camshaft to move independent of the crankshaft.

If you use the correct locking tools when fitting a new belt you should find the timing is pretty much spot on so you likely won't need to follow that procedure.

This guide from the website you referenced is very good and applicable to your engine:

http://www.myturbodiesel.com/wiki/2004-2005-vw-passat-tdi-bhw-engine-diy-timing-belt-replacement-removal/

Combined with the SKF video and erwin you should be all set.

[jimbof]

Thanks, sounds like I'm in action then.  Locking tools already ordered.  Quite looking forward to it now.  

[0wl]

FYI, ECP currently have a good deal on the cam belt kit I used last time, it is an INA kit and when I bought it included a Litens tensioner, INA guide pulley (obviously since it's an INA kit!), two nuts, new studs and I think a Gates belt. ECP are currently selling this for just under £63 if you use the EXTRA15 code. I'd recommend getting an OEM water pump from a dealer / TPS.

[jimbof]

Thanks, I'd found than and got it to pick up later today, together with some replacement Contitech aux and AC belts.

 

£62.89 for the cambelt kit

£12.99 for the aux belt

£34.42 for the HEPU "Made in Germany" water pump with metal impeller (seems this is a hotly debated topic.  my last one fitted was a metal one by the indy - plastic one at TPS is actually cheaper I believe)

 

Tools:

Sealey VSE2358 locking set £12.98

Franklin TA4431 tensioner adjustment tool £18.04

 

So £141 plus the  G13 / Water, only £110 for the actual parts.  Sounds good to me

[fordfan]

 

The bit I don't get is that by my understanding the timing is controlled by the position of the cam pulley relative to the sprocket; changing this relationship changes the timing.

http://www.myturbodiesel.com/wiki/camshaft-timing-torsion-value-adjustment-on-vw-and-audi-pd-tdi-engines/

 

When you fine adjust the timing, you have the belt fitted, You slacken the 3 pulley retaining bolts and then use an 18mm spanner on the centre camshaft bolt to move the camshaft independently of the pulley.

 

If you lock it all down and don't touch the camshaft pulley bolts, the timing should be pretty much as it was with the old belt.

[jimbof]

You do have to slacken the 3 retaining bolts when refitting the belt to avoid locked in torque though, don't you?

I had squared this in my mind as follows: the crank locking tool and cam locking tool keep that relationship constant. Even if you slacken the pulley bolts, the cam and the crank are still locked and the new belt, once tensioned without locked in torque, puts the cam sprocket back where it was, and then you tighten the bolts back up on it.

Picked up all my bits today, interested to see that the INA branded belt is made in the UK. Is that where Gates make them?

Box of treats for the car:

[dieselV6]

It looks to me like the timing belt season has just started  :p .

 

I have just ordered all bits for my Superb's V6 TDI belt job, parts alone added up to nearly £300, even after discounts. Though I did order the full Contitech cambelt kit with hydraulic tensioner, rather than just a minimum set of rollers, belt and the spring tensioner. 5L G13 (TripleQx) , injection pump belt,  2 aux belts and the ripoff airco belt tensioner (does not last, and costs £25-£40 new) made up the rest.  I already had the water pump and the thermostat on the shelf as I had decided not to fit them during the first belt job in 2010.  The car is over 9yrs old, 138k miles and still drives like new, so I might as well do the job properly and enjoy a few more years of Superb motoring :sun: .  Though I think it'll take 2-3 afternoons to replace all bits on the engine, last time it took me ~8hrs in total, without the water pump/thermostat. Locking tools cost me £110 back in 2009.

[jimbof]

Wow, I dread to think what that little job costs at a dealership!

[Gaz]

Wow, I dread to think what that little job costs at a dealership!

 

Mine's due next Spring 

 

Watching the video, it looks like your benchmark is to get it done in 9 mins 22 seconds 

 

Gaz

[jimbof]

Be lucky if I manage it in half a day, am such a paranoid android...

So when you refit the studs into the block; do they get fitted to any torque, or just seated fully home with the torque being applied to the nut?

[Gaz]

Be lucky if I manage it in half a day, am such a paranoid android...

 

I'm sure you'll be fine.  It'll take as long as it takes 

 

Gaz

[jimbof]

Should have used the search function better, I can see the questions on the tightening torque for the studs have been covered previously. Linking to the thread in question for future reference of anyone else: http://www.briskoda.net/forums/index.php?/topic/326252-Timing-belt-change---tensioner-and-guide-pulley-studs

[jimbof]

Well, this is a waste of my time. Crankshaft lock tool has bent locating pin.

[rotodiesel]

This is probably a result of using the wrong tool - or else some idiot has used it as a crank counterhold. There are 2 versions of this tool with slightly differing tooth pitches, one being made to allow for the non-uniform tooth spacing on the later 1.9 PD engines. These are so designed as to accommodate belt stretch as an injector pressurises and loads the belt in one direction and the the associated cylinder fires, accelerating the crankshaft in the opposite direction.

 

The crank lock tools for the later 2.0 PD engines are silver in colour and are completely different in the circumferential positioning of the locking pin.

 

These engines are intolerant of incorrect procedures. Of course, VAG don't always get it right either (they have designed plenty of duff engines) but see my comments in other threads about the tightening torque for the nut on the tensioner stud. Breakage or thread pulling of this stud spells ultimate grief. Draw your own conclusions before tightening the nut.

 

Having worked in detail on many VAG engines over the years, I have concluded that lock washers of any kind are not used by them, in order to cheapen assembly. Stretched threaded fixings are the order of the day in VAG land because they do not incur any extra assembly time or parts cost. The problem is, that sometimes they get this completely wrong.

 

For example, the 4 M8 cap head set bolts securing the TV damper to the crank belt wheel have a "stretch" torque setting, but the holes are threaded to the mating surface, so there is no way that a set bolt can actually stretch at all. So, of course, they frequently break on removal. The fix is to use new bolts with spring washers and tighten them within their elastic limit. Watch this detail when you fit a new cambelt.

 

In Teutonic lands, some manufacturers will never admit to being just plain wrong...

 

rotodiesel.

Edited 2 July, 2015 by rotodiesel

[jimbof]

I should have been more specific, brand new tool out of the packet from the supplier - I haven't been near the car with it yet!  Although I guess it could have been used incorrectly by someone else, sent back and resold!

 

Well, at least it will keep me away from the car in this heat while I wait for a new one to arrive.  I don't need the hassle of faffing around with a damaged tool.

 

I've read the posts I could find on this nut, on this and other forums.  Will probably go for 20Nm + 20 degrees.  I see that INA recommend 23Nm without specifying the 45 degrees ( http://webcat.schaeffler-aftermarket.com/pim/upload/schaefflerDocs/datasheet/base/531056530ea_nonverb.pdf ) - I wonder what that works out to be in degrees over 20Nm?

 

Seen a vid / the odd post where people are using threadlock on the stud, and then 20Nm + 45 degrees, which sounds like a recipe for disaster - the reduction in friction from the threadlock acting as lubricant in its liquid state is surely going to cause a higher amount of stretch being applied to the stud than the dry torque value?

[rotodiesel]

You probably saw one of my earlier threads: 20Nm + 20 deg is my setting. Litens (who make the tensioner) also specify 23 Nm - and having tested this, I can confirm that it amounts to almost exactly the same final tightening position. INA make the self-destruct grease centrifuging small idler.

 

I do not use threadlock anywhere other than specified - which is on the lower belt cover fixings. I use Loctite 222 (pink) which is low strength.

 

Your crank lock tool has almost certainly been abused and returned. 

 

Be prepared for broken TV damper fixing bolts. It is usually easy enough to get the stubs out as the threads don't bind - but it's a pain.

 

rotodiesel.

[jimbof]

You probably saw one of my earlier threads: 20Nm + 20 deg is my setting. Litens (who make the tensioner) also specify 23 Nm - and having tested this, I can confirm that it amounts to almost exactly the same final tightening position. INA make the self-destruct grease centrifuging small idler.

 

Be prepared for broken TV damper fixing bolts. It is usually easy enough to get the stubs out as the threads don't bind - but it's a pain.

 

So 23Nm seemed to be equal to 20Nm + 20degrees?  I may just do that then.

 

Those are the bolts that should be replaced per the manual but aren't included in the kits from anyone, right?! I'm on my 3rd belt, so I think I'll treat her to some new ones, I'm sure they are bound to be the originals still.

[rotodiesel]

If you buy new bolts (good idea) beware - there are two lengths. My AWX has M8 x 37 cap head bolts. The last PD belt I changed was on an Audi fitted with an AVF engine. The bolts fitted to the AVF were M8 x 17 cap head.

 

This sticks in my mind because a bolt sheared on the AVF on attempted removal. Of course, it was a Sunday but I had a spare old AWX bolt which I cut down to complete the job. Getting the broken stub out did not improve my views of VAG design... (last belt change on the Audi was by an Audi dealer - complete with white paint and other bodges).

 

As I always say, EKTA is your friend. It's by far the best VAG documentation and I don't think I've ever spotted an error. Other VAG documentation is lamentable (eg. wrong engine oil spec. in owner's book).

 

rotodiesel.

[oh_superb]

Timing Belt season indeed. I have been shopping around for related bits for my 2.5. The 150000 milestone is quickly approaching! This year will have done 18k MOT to MOT.

Unfortunately the timing belt bits are quite dear, close to £300 with water pump and thermostat. The latter definitely needing changingduento not holding temperature in colder months.

[jimbof]

I don't have ETKA access - I guess you have to be a dealer to get that?  I do have all the workshop manuals downloaded from ERWIN, and I >think< they are the same data just formatted differently (one is PDFs, one is a hierarchical set of SVG's).  

[jimbof]

We car guys are like women; stick a bunch of us together and our timing belt cycles synchronise...! :-p

[rotodiesel]

Trawl around some American websites - EKTA is out there if you look...

 

rotodiesel.