Timing belt - not easy

[Norm]

Hi all,

First things first, I have 1996 Jetta TD, but the manuals I have seem to show different sprockets than those on my car.

The other day the car started to idle rough... shortly after... or within a day or so, it became bad enough that I needed to keep my cold advance lever pulled out all the time otherwise the engine wouldn't idle..   It seemed to be a timing issue... but why ?? After a day of this, it finally stalled ...

 I took the timing belt cover off and it seems to me that the timing belt tensioner wasn't tight enough.  I removed the cam sprocket and the tensioner for a closer inspection.   The tensioner had all of it's tabs bent !!!  I assume it wasn't installed properly by the last person who replaced the timing belt approx. 20,000 back.   It was just sitting there holding the belt but never really working as it should.... probably a fluke that the belt stayed in place for the last 20,000kms.  I suspect what happened the other day is that the other sprockets skipped a notch or two on the belt...  

With a new tensioner in hand, I've attempted twice to line things up, so far with no long term success. I can get things lined up, but come up with a few "problems":

1)
In this picture


you'll notice that I have the belt positioned on the crank and I'm pulling on it to make it snug going to the IP sprocket but the the belt and sprocket notches don't line up.  So far I've settled with not really pulling on the belt allowing it to fit the sprocket, but I think it's wrong.  I believe that I should loosen the bolts maked by the "A" arrow and allow the sprocket to adjust to the belt being snug.   Once everthing is in place ..crank is TDC, cam lock plate is in, tensioner tight and IP lock pin is in then I should re-tighten the three bolts on the IP sprocket.   The sources of documentation that I've found so far does not mention anything about this.   So far I've hesitated to loosen this sprocket because regardless of the tensioner working or not, the alignment of the IP pump sprocket in relation to the other sprockets and crank shaft should remain good.. unless it wasn't done correctly before.. but then, it shouldn't have been running either   Hmmm.. it appeared to run fine before ??  I suppose the pump timing might have been off before but I'm too ignorant to know better?? :oops:   The engine seemed to start fine before..

 Also in the picture below, you'll notice that my IP Sprocket isn't at all like what you find in ANY documentation !!!  All docs that I've found so far, show pictures of a sprocket with round holes and a large pin to hold it in proper timing position ....  this sprocket remains a mystery.   Apparently it's from a newer engine.  Took me a while to figure out how to find the proper timing position.  I'm using a drill bit to hold it in place..

2) The two times that I've attempted to set the timing, I noticed that the car almost stated first turn, but it seems to quickly go out of whack (timing wise ) almost immediately after a turn or so of the engine...  It seems that the belt loosens up and doesn't line up any more ??  

I think the first problem that contributes to this is ...  the tensioner documention that I've been able to find to date seems to indicate that you turn your wrench to the right to tension the belt...or to line up the marks.   This has puzzled me because I have to turn left to get it to tension??  So far I'v been putting the tensioner on the bolt and letting it drop to the position.  It sits fine with locking bar set in the back cover/housing notch and all but this forces me to turn the handle left and not right to line up the marks..   Last night I noticed that if I turn the tensioner adjuster to the top (prior to installing the belt), I will have to turn the wrench to the right to provide tension or to line up the marks.   Hmmm does this make a difference?   It appears that the tensioner would end up being closer to the sprocket as well..  

Right now, I'm sitting here with my coffee, home made wrenches.. pondering my next move....  But I hope didn't damage my valves/pistons  !!   Oops did I forget to mention stress !!

 I've managed to make some crude but functional homemade wrenches for this job,  but if someone can recommend a tool supplier that has reasonable prices, I would appreciated it..   Someday, I'd like to buy the proper tools...

Good advice welcomed..   I'm here for the long haul....

[QuickTD]

I have a TSB on the procedure for timing engines equipped with the new style pulley. PM me your email address and I'll send it to you.

The short version is:

Loosen the 3 bolts in the pump pulley (DO NOT use the pin to hold the pulley in place while loosening the bolts or you will break the pump housing, use a counterhold tool of some kind)

Loosen the camshaft pulley (DO NOT use the cam locking tool to hold the cam or you will break the camshaft, again use a counterhold tool.)

Knock the cam loose on the taper with a drift through the hole in the timing belt cover

Lock the pump sprocket hub in place with a 6mm pin

Remove the valve cover and lock the camshaft with the cam lock tool

Make sure the crank is at TDC

Install the belt starting with the crank and working around to the cam. try to get the pump pulley somewhat centred in the adjustment slots.

Install the tensioner. Make sure the tab is not bent and engages properly with the slot in the timing belt cover. Tension the belt by turning the tensioner to the right until the raised mark lines up with the slot.

LIGHTLY tighten the cam and pump pulley bolts with the locking tools in place then remove them and, using the counterhold tool tighten the cam bolt to 33ft/lbs and the 3 pump bolts to 18ft/lbs

Turn the engine over at least 2 revolutions using a wrench to check for interference.

Replace the covers and enjoy. With the new style pump pulley, the timing is accurate enough that adjustment using a dial guage is not neccesary.

[Norm]

March 25,2005,
Today I installed a new pulley on the crank.  Not too difficult I thought.  I checked the timing a few times and hope that it's in place and proper.   The engine starts good enough however, it doesn't sound good or at least not the same as before.  The engine sounds a bit like a sewing machine indicating to me that there may be one or more bent valves.   Of course, it's possible that I have the timing slightly out.  I'm not certain but, I think that even if the timing was slightly out, I don't think I would hear it. I assume there would be a performance hit but not a clicking sound from the valves... Hmm ..maybe I'm wrong ??  The clicking isn''t always obvious but if you listen good enough you can hear it...especially if I rev the engine a bit.  As the rpms fluctuate, the clicking sound comes and goes.  The other thing I noticed is that it sounds like there is an exhaust-like noise coming from the air breather hose/tube.   Sounds like it's missing.. Although it's a diesel, and there are no spark plugs, it sounds like it mis-fires, rough running?  Once again, all speculation on my part but,  I assume that this may be indicative of a valve not sealing properly allowing cylinder pressure to leak thru the intake valve??

Does any of this make sense?

[QuickTD]

Sorry I didn't get back to you on your last email, been away and them forgot about it... The sounds you are hearing make perfect sense. My guess is there are one or more bent valves causing low compression and misfiring. The clicking is usually the result of crushed hydraulic lifters. When a valve makes contact with the piston the piston drives the stem up and punches a neat round hole in the hydraulic piston of the lifter. After this the lifter will not pump up and you hear the clicking noise. The lifters and valves are not terribly expensive but I would recommend having the crank properly fixed while you're at it. It would be a shame to fix the head and have the pulley come loose again.

[Norm]

Hey QuickTD ever feel like taking a trip to a one horse town to collaborate on a engiine overhaul  <GRIN>.

Ok, I hear you... guess I'll need to pick up more tools !!!  Not sure what I need to buy for a head /valve job.  I have to study that a bit.  I went to pick the crank pulley at the VW dealer and I wasn't impressed.  I felt like I was in their way. . . like I was interupting them !! ahhh , I won't get into customer service or lack of !!

About the crank though...  I didn't think that the key way was too bad at all.   Enough so that I purchased a replacement pulley and installed it.   If I understood you correctly, when you re-key cranks like these, you re-key them to fit a TDI pulley which has a different keyway (a better design  I assume).   Considering it's already purchased and installed  and the key was still pretty nice, I think I'll leave the crank.   Of course at time of purchase, I was hopeful that the valves would be ok..   If I was to start over well... maybe I would have followed you're crank advice.. ( Might have to sooner than I think..)  :-)   I also figure that it makes sense to do the head/valves leaving the engine in place.. makes sense right ?  

QuickTD, I get the feeling that you would replace all of the lifters and valves ?  what else is there valve guides ? Dumb question for you since you're a machinist but, would  you recommend that I bring the head to a machine shop ( one that repairs heads)  and have them inspect the head for unknown issues like warping, cracks etc.... ?  

I need to be coin smart as I proceed.

Have a good evening..  CTV news on next..

[Norm]

Hi Guys,

Can someone tell me which socket I need to remove the head bolts on a 1.9 TD ?  They look like Torx type bolt heads but ... way more then the usual number of points ??  

Is this another VW special tool ?

Have a n ice evening.

[srivett]

They are 12 point (triple square) bolts.  If you need cheap tools quickly they are available at Canadian Tire as a set of 4 under the Lisle brand name.

Steve

[dieselweasel]

Yeah, they're 12mm triple square.

[Norm]

Hi Everyone,

First, srivett & dieselweasel thanks for your reply,you are correct, 12 point triple square.  I had never heard of such a beast and it was a little hard to find as not too many people in the tool business knew what a triple square tool was.. LOL..  but I did find one @ $8.50.

Ok here's a picture of the original problem.....  You'll notice the key missing from the old pulley..


QuickTD you have been correct with everthing to date..  I found one or more lifters hammered by the valve.   The image shows how the center was punctured by the valve stem.



Last weekend, my sons & I took the head off and found a couple of damaged lifters. ... Just like QuickTD predicted.. Not sure if I really needed to but.... I decided to bring the head to a machine shop.   I'm anxious to see what they (machine shop ) we call back with.

I'll post the results...


I'm wondering.... should I replace the head bolts or reuse the old ?

[asau]

the head bolts MUST be replaced

[QuickTD]

You MUST replace the bolts if they have been removed. They are permanently stretched when they are installed. They are pretty cheap anyway. Most aftermarket suppliers sell them for $2-3CDN each. Try to avoid the dealer for this stuff, it'll only sour your opinion of VW's. Make sure you use the same thickness of head gasket when putting it back together.

 Don't let the machine shop tell you the head is buggered beacause of the cracks. They all crack between the valve seats, it's nothing to worry about. I've seen chevy small block types throw away heads because of this... The guides are likely OK but you may need a couple of valves and of course, the lifters.

 If the keyway was tight in the crank it might be OK... You are correct, if I repaired it I would weld up the crank end and use a TDI pulley. The TDI pulley is stronger. It is also far easier to machine the crank for the TDI pulley than it is to machine it to accept the stock pulley again.

 Another thing that helps with "crank pulley syndrome" is a one way clutch pulley on the alternator. This is another TDI part. It prevents the inertia of the alternator from backdriving the crank when the crank slows down. This prevents torque reversals on the crank/crank pulley interface and presumably slows the wear on the key. It also stops the belt tensioner from jumping around, which is wothwhile on its own. The pulley is a bit spendy at $110CDN from an aftermarket supplier but worth it IMO.

[Norm]

Yes I will replace the bolts.

I'm still waiting for the call from the machine shop.   I'm also waiting for two foals.. Hmmm which is more stressful, waiting for the machine shop to call or the foals... LOL...

 Further to the crank pulley,  I have a fair level of confidence that the keyway is in fairly decent condition otherwise I would remove it and probably have it repaired as QuickTD suggested..   At this point, my thinking is get her back together with the repaired lifters/head etc...  Then I will look into finding a clutch type alternator pulley.   Afterwards, I have yet to find the recommended maintenance schedule but I suspect I will perhaps be replacing the crank pulley at the same time as the belt..

[Patrick]

Yes I will replace the bolts.

I'm still waiting for the call from the machine shop.   I'm also waiting for two foals.. Hmmm which is more stressful, waiting for the machine shop to call or the foals... LOL...

If it's anything like my place, dealing with my WIFE while she's waiting for the foals is the problem! :lol:  We're all done for the year already though.

[cipo28]

Hey Norm,
I got the same problem like you had, with my '94 Golf!
I don't know what to do, to fix the head cylinder at the mechanic (but the labour is too high for my pocket) or to do it by myself. In the last case maybe could be easier if I'll find another head cylinder and prepare it properly at machine shop. The thing is they say in the VW manual, special for diesels, that the head cylinder can't be machined!?
Did you fix yours? I'd like to know how engine works.
How much cost you to rebuild the head at the machine shop?
Did you replace the head gasket with the metalic one(upgraded)?

All the best,
Ciprian  

[Norm]

Ciprian,
I had a call from the machine shop late Friday but didn't get a full estimate.  I expect to have my head ready late Monday/Tuesday.  I had three bad  lifters/valve however I'm changing all lifters.  I'll be glad to give you a total  $$$ after...  As far as doing the work yourself, well... I don't have a choice, single income, homeschooling family.   It sure make a GREAT project to teach your young boys  (my hdaughter has no interest..).  
If you get stuck, the guys/gals on this list provide great help.  Incredible to have this community.  

So far my only regret in having to fix this car is that I'm not happy in having to fix the engine before the first car payment..   :x   Having said that, I'm still happy I bought the little diesel....probably will get another for my wife.

have a good evening...