300tdi cam belt failed too soon - why?

Recovered off the m25 yesterday. Cam belt failure.

Symptoms were a sort or flapping sound - i actually thought something was caught in the heater fan, so had a chance to turn the turn that up and down.

Sound went away for a few seconds, then came back. Slowed down to about 60, and got in the inside lane, then, with a puff of black smoke out the back, no power, and coasted to the hard shoulder.

Never any fun waiting in the rain for recovery. Esp when youre on a 5hr drive to a friends funeral : (



But, that aside, i need to get an idea why. Ive just looked up my order history, and i bought and fitted this in October 2013 -

TIMINGKIT300L | Timing Belt Kit - 300TDI later type

(paddocks kit / dayco belt)

So, it has not lasted long. The disco has not been waded. The IP is not leaking (that was the reason for doing the cam belt before) and the tension, although not measured, was agreed by two experienced friends before reassembly.


What im trying to work out is if this is bad luck, or operator error in some way or other.

(im miles away from home at the moment, and have not started taking stuff apart yet)

Thank you,
Julian

That's not good news Julian, hope you get it sorted.

Was it Jules that checked the tension ?

julianf said:

Recovered off the m25 yesterday. Cam belt failure.

Symptoms were a sort or flapping sound - i actually thought something was caught in the heater fan, so had a chance to turn the turn that up and down.

Sound went away for a few seconds, then came back. Slowed down to about 60, and got in the inside lane, then, with a puff of black smoke out the back, no power, and coasted to the hard shoulder.

Never any fun waiting in the rain for recovery. Esp when youre on a 5hr drive to a friends funeral : (



But, that aside, i need to get an idea why. Ive just looked up my order history, and i bought and fitted this in October 2013 -

TIMINGKIT300L | Timing Belt Kit - 300TDI later type

(paddocks kit / dayco belt)

So, it has not lasted long. The disco has not been waded. The IP is not leaking (that was the reason for doing the cam belt before) and the tension, although not measured, was agreed by two experienced friends before reassembly.


What im trying to work out is if this is bad luck, or operator error in some way or other.

(im miles away from home at the moment, and have not started taking stuff apart yet)

Thank you,
Julian

Click to expand...

new parts can fail even decent parts , worth checking to see if any have when belt is off by turning all by hand

markSX said:

That's not good news Julian, hope you get it sorted.

Was it Jules that checked the tension ?

Click to expand...

Yep, and Pete was picking up "The Van" that day too, from the next village along from us, and helping out (drinking tea) also...

I'm miles from home now (about 250) but i borrowed a puller and stuff this evening, so ill start on things tomorrow.

I'm hoping its just pushrods / rockers. People say valve damage is fairly uncommon, but im not sure about cam follower damage?

Right, i dont understand this, but then i dont have much experience in these things -

Took the rocker assembly out - got an entire set of bent pushrods.
Looked down all but the last opening at the cam followers - cant see any issues, but the cup isnt that clear to see.

No immediately visible rocker damage, but ill inspect them closer later.

So, at that point, it wasnt going too badly...

Took the timing belt cover off. Belt is still in place, but has been de-toothed around the cam pulley. Half the timing belt case was filled with 'fluff' but i guess that's expected.

Where the belt was not de-toothed, it looks ok.

Nothing appears ceased. The tensioner pulley is smooth enough. It does not spin on when you flick it, but its quiet. The idler pulley spins on after a flick, but sounds a little ropey - but nothing that scary.

I cant remember how much force the ip should take to turn - it takes a fair bit, then flicks around about 180 degrees again. As i recall, this is about right?

The cam pulley turns with some squelching sounds, but, again, thats to be expected, right?


The damage is as if the cam shaft pulley has locked, and evreything else has carried on turning, but im having troubles with the chicken and egg thing of what went wrong first.

Im hoping that someone with more experience than me will recognise the symptoms (flapping sound, that went away, came back, went, then failure) and give me some ideas before i put the thing back together again, and the same thing happens again.

Thanks,
Julian

ip pump is functioning fine from what you say ,you need to look down to the followers for seat damage , put crank key at 9 or 3 oclock and put a push rod down to each follower in turn press down reasonably hard and turn cam feeling for rough or notchiness through push rod, seems like fault was caused by cam been momentarily jammed from what you say ,

Thank you - will do. Have come in for the day, so will be tomorrow morning now.

It did not make sense that the teeth would only strip around the cam pulley, as, of course, the wheels would still be turning, so the crank likewise. I went back to my photos to check, and, sure enough, its the crank that was eating the belt.

Ive also had a better look at the belt, and there is some ware to the outer edge - a groove to about 1mm in from the edge, on the outside of the belt.


Ive taken a stack of photos. Most are all the same, just from different angles, but ive uploaded the lot to photobucket.

Folder -

Cam Belt Photos by julianfincham | Photobucket

and a couple of examples -

youve got the wrong crank pulley you need lhh100660 google it and youll see, still check followers as i said

Thank you. You know ive even read that service bulletin in the past, and then... : /

Do you reckon that's the cause then? Its an N-reg, so '96. I dont know the vin number off by heart (!) but as i ordered the "Timing Belt Kit - 300TDI later type" last year, i guess its "from VA560898".

Id be very happy if its as simple as that. I hate it when things break, but you dont know why.

(and, yes, will check the followers)

jamesmartin said:

youve got the wrong crank pulley you need lhh100660 google it and youll see, still check followers as i said

Click to expand...

whilst i dont doubt you are correct, James - if he hasnt changed the crank pulley - that means it was incorrect before hand - and that didnt cause a problem,I assume. So why the problem now?

The Mad Hat Man said:

whilst i dont doubt you are correct, James - if he hasnt changed the crank pulley - that means it was incorrect before hand - and that didnt cause a problem,I assume. So why the problem now?

Click to expand...

he probably had the early type setup with the lip on the tensioner.

but then went and bought the late type kit; which moves the lip to the crank pulley and removes it from the tensioner.

that kit doesn't come with a new crank pulley, so he effectively removed any guides.

he should have bought the early kit, or changed to the later setup by having the later crank pulley with a lip

that crank pulley would have had the tensioner with the belt guide lips , they changed it to crank pulley having the lips as some belts not all were wearing on the edge ,was the tensioner changed for later non lip one thus leaving no guides to steer belt or was he just extremely lucky before
info in op is a little misleading as it may have some teeth off but belts only half as wide not quite enough to drive ip and cam

to beat james to it, the number for the full upgrade kit which includes the new pulley is STC4096L

More background info -

When we did the belt before (with the latter style kit) it was done as a precaution, as the IP had been leaking into the timing belt case.

...so the belt was done prematurely, but looked in good condition when done.

Im told it was done shortly before i purchased the vehicle though, so had not been on there long.


But -

Im 90% sure that the parts removed were the same as the parts fitted (ie no lip). In fact, im a bit more sure than 90% - i still have them knocking about at home somewhere, so i can check to be certain.


It may have been that the belt that got fuel leaked on it was just compatible, or it may have not been on long enough to fail.


When you say -

info in op is a little misleading as it may have some teeth off but belts only half as wide not quite enough to drive ip and cam

Click to expand...

Are you saying that the belt should be much wider, and that half of it has worn away (so what i thought was the 1mm nick out of the edge was actually just the border of what had been eaten?)

(like i say, ive not seen enough of these things to know, or remember)

not mine, but to give you an idea:



i'd really get the new crank pulley with a lip on it, if none of the parts before had a lip, then someone mucked up previously

julianf said:

More background info -

When we did the belt before (with the latter style kit) it was done as a precaution, as the IP had been leaking into the timing belt case.

...so the belt was done prematurely, but looked in good condition when done.

Im told it was done shortly before i purchased the vehicle though, so had not been on there long.


But -

Im 90% sure that the parts removed were the same as the parts fitted (ie no lip). In fact, im a bit more sure than 90% - i still have them knocking about at home somewhere, so i can check to be certain.


It may have been that the belt that got fuel leaked on it was just compatible, or it may have not been on long enough to fail.


When you say -



Are you saying that the belt should be much wider, and that half of it has worn away (so what i thought was the 1mm nick out of the edge was actually just the border of what had been eaten?)

(like i say, ive not seen enough of these things to know, or remember)

Click to expand...

should be a bit wider halfs a bit of an exaggeration, but as much edge wear as your belt is very diagnostic, if belt runs ok without a guided pulley ideally crank pulley its luck if it stays central on pulleys ,injection pump mount to was changed as people often pulled ip out of line by pulling up the slack on the bracket by the bolts

Got most of the parts now, but need to make up another puller for the crank sprocket (should have done it yesterday, but did not realise it would be as hard to get off)

Anyhow, setting valve clearances -

Seems like it would be easier without the cam belt on, with the pistons at mid points.
This is 1/4 of a turn beyond TDC, right?

Is setting the valves before fitting the belt a reasonable idea, or all wrong?
I figured i could turn over the cam by hand and check all the valves were moving freely, without having to work against the compression.


In other news -

Ive got the new pushrods in. Could not feel any issues when pressing them in by hand. All go up and down with the cam as expected.

Had the rocker assembly apart. Centre looks ok. One of the rockers had me looking at it for quite a while, as it had a scuff on the face, but im sure enough now that its a scuff and not a fracture.

So, this all went back together again today, but not running...

My timing procedure (so as someone can tell me where i went wrong) -

Set crank woodruff to 12 o'clock. Checked (visually) that the groove in the flywheel could be seen through the bellhousing.

Put motor into 5th gear with handbrake on.

Rotated IP and put 9.5mm drill in.

Set cam sprocket line with mark on the pillar (ie about 8 o'clock)

Put on belt. In the absence of any fancy kit, i pulled up the tensioner with one hand and tightened the tensioner up with the other. Cant pull belt through 90 degrees due to obstructions, but i reckon i could if there wasnt stuff in the way.

Tightened down the rocker assembly, making sure it was all seated right.

Then did all the valve clearences. Took out of gear, and rotated the crank to watch which valve opened, then used the rule of 9 to set the clearence on the closed valve to 0.2mm. All valves seemed to be travelling smoothly and as you would expect. Needed to adjust the clearances a bit (new pushrods) but not loads and loads.


I did *not* loosen the three IP pump bolts, to rotate the sprocket. Firstly i did not understand quite why i should (as the drill was in there) and secondly, one of the heads is rounded.

Put the cover back on, and crank dampener / bolt, rad top hose, etc.



Turned the keys.

Sounded pretty ropey. Seemed like it was trying to start, but would not maintain independently of the starter motor. (ie almost seemed to run, but only when the starter was turning). Lots of blue smoke.


Spoke with a friend on the phone, who suggested trying different postions on the IP sprocket (ie advance or retard to full travel, give it a go, see if there's any difference) but, at the moment, i cant get a socket to purchase on one of the 10mm heads. So it looks like i need to take the cover off again to get to it from the side with a spanner / grips etc.



So -

Ive tried to be detailed above, in the hopes that someone can spot my error?
Last time the belt was changed, i cant recall adjusting the IP sprocket, so i figured it would be ok this time, but, evidently, something is wrong.

Any pointers?

when you do a cam belt you set up tighten turn engine over twice and redo ,on the front of crank pulley is a dot which needs aligning with arrow on the case, your bolt if hit a few times weill loosen