Diesel pump sprocket and timing Question

[John Plum]

When fitting a replacement auxiliary drive belt on a diesel, if the fuel injector pump sprocket were to be moved (ie. rotated), would that cause a timing problem.

If so, can that timing issue be resolved, by lining up the flywheel timing holes and injector sprocket holes?

The benefit of your experience on citroen diesels is highly valued by me!

[Sean602]

if you havent touched the timing belt then nothing can change
BUT - if you loosen the crank pulley then there is a chance that you could disturb the timing as the crank pinion( timing belt pulley) has a range of movement and will move if the pulley is loose and either the top of the lot is moved or the crank is moved - ideally you should peg the flywheel and one of the top sprockets

see http://www.frenchcarforum.co.uk/forum/v ... =3&t=43768

if its HDi engine with common rail then its only cam and crank that need indexing as the pump has nowt to do with timing it only feeds the rail with high pressure diesel

[citronut]

firstly John i think you mean the cam belt not aux drive belt

if that so on an XUD you should peg/lock the pump sprocket so it cant move, and if you did not peg/lock it off and only the pump sprocket moved, this will just put the pump timing out, so yes it can just be re/set,

if its a HDI the pump sprocket moving will not cause any problems that im aware of

[John Plum]

Thanks Saun, makes good sense; nice ref.

To confirm, when I ask 'would that cause a timing problem', I mean fuel injection timing. Wouldn't that be affected?

It's not an HDI, it's the Xantia TD XUD9FE with bosh pump

@Citronut you seem to answer my refined question, but I should confirm, it was the auxiliary drive belt, not the cam belt being replaced.
From what you say, I deduce that injector pump sprocket rotation, would upset pump timing, and that pegging the drive flywheel and lining up the said sprocket before refitting the belt would solve my non-starting problem.

[Old-Guy]

Simple, short answer to your original question: NO.

The auxiliary belt (ridged, drives alternator, A/C compressor, hydraulic pump) has nothing whatsoever to do with the timing - unless it disintegrated and a shred got between the (toothed) cam-belt and a toothed sprocket (usually the crank-shaft).

If the tension on the cam-belt is slacked off, then you could lose timing as both the camshaft and fuel pump tend to move themselves if not pegged - never mind you turning over the fuel injection pump. If you don't re-fit the cam-belt with flywheel, camshaft and pump all pegged, and take up the slack correctly before re-tensioning then it would be easy to get the timing one tooth adrift. BUT if you haven't slackened off the cam-belt you can turn the engine over until the cows come home without upsetting the timing.

What else did you do at the same time? Fuel filter?

[Sean602]

cant see how the pump could turn unless you had removed the toothed timing belt If the belt is disturbed for any reason then you have to peg it all up to make sure its ok
remember that if you turn the crank over once the pump or cam wont line up you have to turn it over an even amount and then check that all the holes line up again

its simple enough to check - just peg the flywheel and make sure the timing tool/suitable sized socket fits in the hole in the timing pulley and the pin goes in the cam ( you may have to find the crank peg - then turn it over once to get the cam and pump to line up again)

Sean

[John Plum]

Thanks to all. OK clear on this then.

@ Old-Guy : didn't do the fuel filter at same time.
I Fitted a new belt - too long; engine started and ran fine fine, but couldn't get enough tension. Promptly fitted with shorter belt, it started roughly, misfired and then wouldn't start.

I'll check under timIng cover for signs of the original shredded belt and, for timing.
Perhaps after a fuel delivery check.

Thanks again to y'all for kind advice.

[citronut]

John your original question says "auxiliary drive belt" , as Old-Guy says this has nout to do with driving the fuel pump,

did you actually have an auxiliary drive belt shred/fail?????

[John Plum]

@citronut yes, the aux drive belt began to fail close to home.
I see I made a dumb mistake in my question.

I've managed to pin the crankshaft with a bent rod, observing it rise and fall to make sure it's home into the flywheel slot (can't actually get sight of it, you know). LOoking at the injector pump pulley pin holes, it appears the timing belt may well have jumped a tooth; l'll fetch a new belt and fit it.

Q: how do I best lock the crankshaft on an auto TD in order to remove the crankshaft pulley retainIng nut?
Is it best to leave it in park and have someone press hard on the foot brake?

Q: Is there a retaning bolt at the rear edge on later models rear timing belt cover?

Cheers, John

[citronut]

@citronut yes, the aux drive belt began to fail close to home.
I see I made a dumb mistake in my question.

no worries John
i was just trying to clarify the story

Q: how do I best lock the crankshaft on an auto TD in order to remove the crankshaft pulley retainIng nut?
Is it best to leave it in park and have someone press hard on the foot brake?

Q: Is there a retaning bolt at the rear edge on later models rear timing belt cover?

Cheers, John

im not sure on an auto apart from dropping the starter out so you can get at the ring gear , i would use a hammer/rattle gun on the pulley bolt

[Sean602]

long breaker bar, click the starter. someone brave will have to keep an eye on the breaker bar it has to be tight against floor and its just a click on the starter don't spin it

[Old-Guy]

Q: Is there a retaning bolt at the rear edge on later models rear timing belt cover?

I believe so, but can't say with absolute certainty. On mine (v.late 1995), its a long bolt with it's 12mm head underneath the fuel return (to the tank) pipe which is itself under the two air ducts to/from the turbo-charger. IMO it's worth removing the two air ducts - sounds like a lot of work but it makes it sooo much easier to get at this bolt, get it out, remove and refit the top part of the belt cover and then get the bolt back in. The last is the hardest part as the bolt is angled up into the head with it's axis is parallel to the block/head joint.

The connections on the turbo really aren't that hard to undo - once you know the secret: the flange on the outlet duct on top of the turbo is held on by two setscrews with 10mm heads - with a torch shining down the back of the engine, you can see the head of the set-screw nearest the block by looking down between cambox and inlet manifold , there's even a cut away in the cambox.

PM me with an e-mail address and I'll send you some pictures and more detailed notes - I'm in the midst of re-vamping my website which will shortly have these and lots of other pix on it.

[John Plum]

Thanks guys.
I took the starter off to get at the crank TDC alignment hole. I liked the idea of the breaker bar and starting motor, but as I've pegged the crank, its OK, and so I removed the pulley.
Yes, there is an inaccessible retaining bolt at the back of the rear timing cover on mine, I am sure now. Cheers for the encouragement @Old-Guy, in getting to it.

Q: I have encountered a real problem in setting the timing of the camshaft. I am not sure of the correct alignment position.

At about 2 o clock on the camshaft sprocket, there is an a`adequate threaded hole in the engine casing behind, to take an 8mm bolt.
At about 7 to 8 o clock behind the cam sprocket, is a hole in the engine casing, but blocked from recieving the 8mm bolt, by a pressed in ball bearing.


I suspect the last one is the correct alignment position to the alignment hole in the cam sprocket.
Is anyone familiar with this design?

What follows is my observation upon stripping down the timing covers and belt:

With original timing belt intact and in position upon removal of covers, I found the cam sprocket, marked with white at its pinning hole, at about 220 degrees from the top (or 7 0 clock).

It seems the threaded pinning hole at 2 o clock cannot be right. Fitting the belt there, I cannot rotate the crank for valves come against the pistons. Its obviously the wrong position - or I have bent/stuck valve(s).
I double-checked the pinning of the crank at TDC, with alternator removed, using a 6mm bolt, and am satisfied.

With original timing belt still on, upon removal of covers, I had noticed a fistful of aux belt shreds stuck at the crankshaft pinion, trapped under the timing belt; I question wether the timing belt could not have jumped from 2 o clock to 8 o clock. I found the injector pump pinion seemed to in in the right place, with its two holes, more or less, lined up.

Perhaps the timing of the cam and fuel injector sprockets, as I found them, was more or less right, with the cam mark being at between 7 and 8 o clock.

Makes me wonder, whether my starting problem, before I checked the timing belt after fitting a new auxiliary belt, might have been due to the timing belt slipping round the shreds caught on the crank pinion wheel.

[Old-Guy]

I can't quite make sense of your clock positions. If you have a look at the picture of an XUD9 engine on page 3 of this pdf, the camshaft and pump are near-enough in the pegged positions. It's vital to fit the belt starting from the cam-shaft, taking any slack out to locked pump to crank-shaft.

In the light of changing the cambelt (while doing the head gasket), I have revised my method as follows:
"The spring-loaded plunger (green arrow above) that provides automatic tensioning makes the tensioner
a sod to re-fit. The tensioner rotates on a pin - make sure this is free of rust and lightly lubricated so
that the tensioner sleeve slides smoothly onto it.
Clean and lightly grease the plunger and spring. The plunger
and spring WILL fall on the floor – so spread a large clean
rag or dust-sheet on the floor to save having to keep
cleaning them. With the tensioner ready to hand, fit the
spring and plunger. Using the idler as a fulcrum for a
suitable lever (with no edges to mark the idler wheel)
carefully lever the plunger upwards as far as it will go (until
the corner of the bracket gets in the way as in the photo).
Push the tensioner onto its pivot and under the plunger as far
as it will go; the mounting bracket will stop it going the last 5mm or so. Now from below, with the end
of a hammer handle or similar, push upwards and then sideways on the tensioner flange that the
plunger rests on. With the plunger compressed, the tensioner will then slide fully into place. Pressure
on the plunger can now be released so the tensioner jams against the edge of the mounting bracket. Fit
the nut on the tensioner pivot. With your 'special tool' rotate the tensioner fully clockwise against the
spring and lock off with the pinch-bolt.
Now fit the timing belt carefully – teeth to sprockets, smooth back to idler and tensioner wheels: Over
the camshaft sprocket, round the pump sprocket, between the idler and the bracket (where the lever is
in the photo), down round the crankshaft sprocket, round the water-pump sprocket and inside the
tensioner. Once it's following the right path, take out the slack: hold it on the teeth of the camshaft
sprocket, lift it off the teeth of the fuel pump sprocket and pull out any slack before re-engaging on the
sprocket. Repeat for fuel-pump to crankshaft sprockets. The belt must be reasonably tight from
camshaft to fuel-pump to crankshaft, with all the slack between the crankshaft (via water-pump and
tensioner) and the camshaft. Carefully release the tensioner and check there is only the slightest
slackness from camshaft to fuel-pump and fuel-pump to crankshaft. Nip up the tensioner pinch bolt."
Re-fitting the tensioner this way was pretty painless.

Personally, I've not encountered the shredded belt problem, but other people have reported exactly finding shreds like you did and then found that timing had slipped a tooth (or two). I think you might have been really unlucky in that the shreds got trapped only when you re-started after changing the belt.

[John Plum]

Thank you @oldguy. I checked the ref and the cam position on page 3. Looking again at my engine orientated as per picture, the threaded hole to align the cam, is at the same, at 4 o clock - (a correction to 2 o clock which I wrote above).. This is, I just read, the expected XUD position.

Trouble is I couldnt turn the crank with new belt fitted to that alignment.

I found the cam at 7 o clock when stripping down, (apparently the hdi position), with crank and fuel pump sprockets pinned.

Maybe I have damaged valves, but I suspect the problem may be cam alignment.