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Dear all,

I'm looking for advice on the correct timing belt tension on a 1.9TD P reg ‘96 XUD9. DHX2.

I’ve had about 1/5th width of the auxiliary drive belt end up in the timing belt casing. I found all the belt debris. When aligning the engine, the pump and valves i believe have advanced 1 tooth to the flywheel. At present belt tension seems to be a little slack too. Engine fault light is on.

The auxiliary belt and automatic belt tensioner are sorted.

I think that the timing belt needs replacing (35K miles/4 yrs old) since the surface condition doesn’t look good with lots of slits along and across the belt. When i last did the job 500miles later the timing belt skipped and being along way from home i had to take it to a garage. After this incident i’m a little concerned about getting the correct tension. I would have taken it to garage this time but a recent change in personal circumstances dictate that i do the job.
I seem to recall when i last changed the timing belt that the automatic timing belt tensioner applied very little pressure so i applied additional tension manually. After the job there was no odd strange noises so i don't think that i had applied to much tension.

My grandfather always said 1/4inch maximum give from a straight edge at the mid point of a belt’s longest length. I’ve also heard about a 90 degree range of rotation across the width of the belt. I’d be grateful for any advice.
Thanks

Set up the timing by fitting the timing pin in the hole under the starter motor and into the flywheel to lock it.
Fit the bolts through the injection pump pulley to lock it.
Fit the bolt through the camshaft pulley to lock it.
Undo the bolts holding the tensioner and force it against the tension, then tighten one bolt to hold it back.
Remove the old timing belt.
Fit the new belt around all the pulleys.
Slacken the bolt holding the tensioner back and let the spring tension take the tensioner onto the belt.
Remove the bolts from the camshaft and pump pulleys and remove the crank locking pin.
Leave the tensioner bolts loose, fit the crank pulley and bolt then turn the engine 2 full turns clockwise.
Get a spanner on the camshaft pulley and GENTLY tap it to the left a tiny bit until the tension on the belt is tight on the injection pump side.
Tighten the tensioner locking bolts.
Refit the bolts through the injection pump and camshaft pulleys and the locking pin into the crank to check the timing.
If the locking bolts and pins don't go in, start again with the lining up.

If the tensioner pulley turns too easily, the tension may not be right, the tensioner pulley should have strong resistance to turning against the belt. remembering that the injection pump side of the belt should be tight.

Many thanks.
I'm nearly there with the belt, just have to degrease the sprockets and put the new belt on but the weather is against me.