Help with 300tdi timing

[Sharp]

I'm having some issues with fitting a new timing belt and looking for some help. (Mark on cam pulley not lining up and struggling to get the belt on)

It's a 1998 300tdi with the new timing kit (tensioner without the lip). Upon taking the casing off the belt was quite badly worn which I had attributed to the previous owner putting too much tension on the belt. You could see where the belt had ridden to the edge of the FIP pulley and worn against the casing creating lots of black fluff in the bottom. The idler pulley and tensioner were both in good condition.

I rotated the engine till the woodruff key was at 12 o'clock with the timing pin in the bell housing until it clicked then put the 9mm pin in the slot in the FIP pulley and noticed the mark on the camshaft pulley didn't line up with the arrow on the casing.

I figured it's probably fine, as the engine has been running well. But I'm now struggling to get the belt on and wondering if this is the problem

That's as close as I've been able to get it and it's not enough to get it around the FIP pulley (3 bolts are loosened). I've heard it's quite a struggle to get on so I'm not sure if I'm not forcing it hard enough or whether there is something wrong. I saw on one of Mike's video that he recommends taking the idler off once the tensioner is fitted, fitting the timing belt and then putting the idler pulley back on. I haven't tried that, but wanted some advice on whether something might be wrong with the cam position before trying to force it more, as to my eye, the belt misaligns about the same amount as the mark is off. I'm not sure how much force the bellhousing pin can take, but I've given the bolt a wiggle in each direction and can't create any play with the force I've put through it, the woodruff key looks to be pointing straight up.

Like I say, it has been running really nicely for a few years, the only thing recently is very occasionally it will over rev for a second without any extra pressure on the accelerator peddle, but I don't imagine that's anything to do with the timing. Any advice appreciated

[steve b]

I have the idler loose enough to rock over but not allow the tensioner to come off the pivot spigot. 

Belt on crank then cam then FIP . 

The cam wheel not lining up could be crank drive wheel key/keyway issues?

Steve

[stevebus]

If its been running OK I'd probably stick with the mark as long as it isn't a complete tooth out you'll be OK, I've had the odd engine not quite line up for whatever reason, maybe your photo is like looking at the fuel gauge when your sat in the passenger seat if that makes sense, your not that faraway, but while you have it all apart like Steve b says have a look and the keyway, and if Mike's video your referring to Mike tomcat, I'd do as he says really, fella definitely seems to know his onions, good luck

[fmmv]

Have you tried moving the belt a tooth on the crank pulley and seeing if it lines up with camshaft at the mark?Don't worry about the rest till you have the crank and cam as near correct as you can. I bought a vehicle that looked similar, it ran but when timed right the difference  running was night and day

Edited October 21, 2023 by fmmv

[Sharp]

7 hours ago, fmmv said:

Have you tried moving the belt a tooth on the crank pulley and seeing if it lines up with camshaft at the mark?Don't worry about the rest till you have the crank and cam as near correct as you can. I bought a vehicle that looked similar, it ran but when timed right the difference  running was night and day

Do you mean taking the pin out of the bellhousing that's locking the flywheel and rotating the crank pulley?

[toenden]

If you have a locking pin in the crank then turn the cam to its mark, and from your pictures it seems like the belt will fall into place? 

As fmmv says, they will run pretty much out of timing, but the difference in output is big 🙂

/mads

[fmmv]

I would get crank pulley and cam pulley in correct positions, ie flywheel pin in and cam pulley opposite the mark. Then put the the teeth of the belt on the cam pulley first and go round the idler and crank pulley with a bit of tension on the belt. It should all fit, there may be very slight movement needed as the crank lock may be slightly sloppy. That should get cam and crank correct without fighting with the rest. Then fit the belt as normal without moving the cam. It looks to me from the pic the cam isn't timed right  A new belt can be a bit of a swine to fit, they can be quite tight to slip on, but persistence pays. You got the crank pulley off so you've got this.

Edited October 22, 2023 by fmmv

[Sharp]

Thank you for everyone's help. I had another go at it this morning, using Mike's technique of removing the idler pulley before positioning the belt, and refitting it once the belt is on (TY-"300Tdi timing and tensioning the belt"). It went on quite easily doing that. I guess we'll see how it runs, but provided it doesn't go up in a cloud of smoke then I think I'll have it off again in a few months to see how it's running. The crank is leaking a little and I didn't have the right bolts (100mm M5 I think) to get it off so that will need doing at some point.

I'm reluctant to tinker with it seeing that it's been running ok and I don't know what I'm doing with adjusting the cam pulley, but it sounds like perhaps it's not set up quite right and I can't do much damage by adjusting it. I take it that to do so is just a case of rotating it by the big nut in the middle?

I also noticed the pump isn't quite aligned when the crank is locked.

Oh and no props deserved for getting the crank bolt off, I just removed the radiator and hit it with the impact!

[fmmv]

To move the camshaft pulley just put a spanner on the big nut, with the belt off I am assuming. You can adjust the pump position by loosening the 3 small bolts.

[fmmv]

When you replace the oil seal, dont forget to also replace the big O ring behind the crank pulley as well.

[Sharp]

2 hours ago, fmmv said:

To move the camshaft pulley just put a spanner on the big nut, with the belt off I am assuming. You can adjust the pump position by loosening the 3 small bolts.

The three bolts just allow the outer pulley to rotate (the gold bit) for fitting the belt. It's hard to see in the picture, but if you look inside, past the gold part, you can see the internals don't quite line up.

[Sharp]

1 hour ago, fmmv said:

When you replace the oil seal, dont forget to also replace the big O ring behind the crank pulley as well.

Annoyingly I have all the seals and the o ring, but thought it was m6 bolts that went into the crank but they were too big.

[steve b]

In your first post you said 9mm pin in the FIP lock, I use a 3/8" drill bit , 9.5mm . The fit is very tight but needs to be.

The crank drive wheel key/keyway is still my prime suspect regarding cam wheel position.

Steve

[Peaklander]

1 hour ago, Sharp said:

It's hard to see in the picture, but if you look inside, past the gold part, you can see the internals don't quite line up.

That’s because the fip flange has been mounted to the shaft just a little bit off, at the timing position that your 9mm drill timing pin would need.

[Sharp]

2 hours ago, steve b said:

In your first post you said 9mm pin in the FIP lock, I use a 3/8" drill bit , 9.5mm . The fit is very tight but needs to be.

The crank drive wheel key/keyway is still my prime suspect regarding cam wheel position.

Steve

That's interesting. I had read of other people saying that. The pin in the timing kit is 9mm and that was a tight fit.

[Sharp]

1 hour ago, Peaklander said:

That’s because the fip flange has been mounted to the shaft just a little bit off, at the timing position that your 9mm drill timing pin would need.

Sounds like it's not a problem then, if I understand you correctly. Just put on a bit wonky.

[fmmv]

If Mr @steve b is correct in his concern re the keyway, you would be wise to pull off the pulley and check it out before running it again.

[Sharp]

It's been out for a test run but I have no trips planned in it for a while so perhaps I should look at it sooner rather than later.

[Peaklander]

On 10/22/2023 at 5:16 PM, Sharp said:

Sounds like it's not a problem then, if I understand you correctly. Just put on a bit wonky

The timing of the pump (at overhaul) is set with a dial gauge at the back. When it is at the correct position (normally 1.57mm of ‘lift’) , the shaft is locked. Then the flange is positioned and locked on with the big nut (that isn’t normally moved). It is put on so that the timing pin goes in all the way. The shaft is then unlocked and is free to turn. Then later you can just use that pin position, knowing that the pump timing is correct.

Apparently there can be wear in the pump and I think that’s why a looser pin (smaller diameter drill bit) is sometimes used, which I think advances the timing. 🤷🏻‍♂️ need to think a bit more about that though. 

[Eightpot]

You may be over thinking things here - the process to change the belt is get to tdc so you can fit timing pin, then slacken the 3 sprocket bolts on fip. Take belt off. Get flywheel notch to line up with bellhousing hole. Rotate cam of necessary till mark lines up. Fit idler/tensioner but fairly loose. Fit belt round crank/idler/tensioner , then round cam sprocket making sure belt teeth are down snug - if belt teeth aren't snug on cam, move cam a fraction till it does.  Belt should now slide tightly over the slack pump sprocket a little at a time - should be no need to remove pulleys etc. If you want to fine adjust how the pump is timed now is the time before nipping up the three bolts.  Adjust belt tension, remove pins rotate a few times then check pins slide back when marks align. 

[Sharp]

Thanks for that. "Rotate cam if necessary till mark lines up." - that was the bit that was a surprise to me, as in manual and all the resources I've read and videos I've watched I hadn't seen it mentioned that the cam needed to be adjusted during a timing belt change. When I've done belts on other vehicles, once everything has been locked up nothing has needed to be adjusted as part of the precedure. I had thought that once the flywheel and pump were locked, the marks on the cam should line up and everything should be kept in place until the new belt was fitted and tensioned up. Every day is a learning day! It does sound like it's probably worth checking the crank gear before I adjust anything though.

[Peaklander]

The locking of the crank at the flywheel sets #1 piston at the correct position (firing tdc) and the pump is locked at its previously setup position with the pin. The camshaft is the one point that is free to move and is set manually at the correct position, indicated by the marks. 

[fmmv]

I think the manuals, video etc assume that the cam is already in line with the marks when you take the old belt off.

[oneandtwo]

Classic case of 300tdi misaligned timing cover casing / fuel injector pump causing the belt to run off the pulley.

You need the revised injector pump bracket with sliding bushings to prevent it happening again.