Citroen quasi adjustable crankshaft sprocket

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Taffyrhys
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Citroen quasi adjustable crankshaft sprocket

Post by Taffyrhys »

Hi Team

I have a Citroen Xsara Estate 2.0 HDI, which has a quasi adjustable crankshaft sprocket (the one with the wide key way). I understand this is to set the timming and allow it some adjustment

I'm going to change the timing belt, which I have completed on my other cars but was wondering how the cam sprocket should sit, should the wide key way be centralised against the key or should the key be position at one end of the key way????????

Any guidance would be helpful, Soon be pub Friday :)

Cheers
BX
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Re: Citroen quasi adjustable crankshaft sprocket

Post by BX »

Lock the camshaft and crankshaft using the appropriate locking kit (or bolts/pins).
Replace the belt and adjust tension as per instructions.
Remove the locking pins. Rotate the crankshaft 8 revolutions.
Retension the belt. Refit the locking pins to the crank and cam. Replace the lower cover and the pulley. On tightening the pulley retaining bolt the crankshaft sprocket is locked in position. It will have taken up the correct position by itself.
I am sure that this is better explained elsewhere.
Taffyrhys
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Re: Citroen quasi adjustable crankshaft sprocket

Post by Taffyrhys »

Thank you for the reply but you haven’t explained how to position the crankshaft sprocket , which has the wide key way so the sprocket can move 2mm in either direction? and Isn’t locked.

Any help would be great 😃😃👍
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Paul-R
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Re: Citroen quasi adjustable crankshaft sprocket

Post by Paul-R »

It's been quite some time since I did the timing belts on our old Xsara and Mk1 C5 but ISTR that on the C5 it should have involved using a drill bit of a particular size to pad out the space on one side of the woodruff key. In reality I wasn't able to do this because the woodruff key had been distorted by a previous owner and there wasn't any free play!
RichardW
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Re: Citroen quasi adjustable crankshaft sprocket

Post by RichardW »

Make sure both crank and cam pinned, set the sprocket to the centre. Feed the belt on from cam to IP to crank, rotating the sprocket as necessary, then get it fully on. Now set the tension, which will allow the crank sprocket to rotate. Check the sprocket is not right at the end. Refit the crank pulley, turn the engine over, re pin, remove the pulley again and check the sprocket is not right either way.
Steve Walsh
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Re: Citroen quasi adjustable crankshaft sprocket

Post by Steve Walsh »

Done mine recently on a c5, There is an excellent guide on here by'' Marc, Give me a break''.... There is a special tool listed, I used a couple of bits of wire either side of the key to centralise it, Very easy to do.
When you see it it will be obvious

Steve
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Paul-R
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Re: Citroen quasi adjustable crankshaft sprocket

Post by Paul-R »

Paul-R wrote:
17 Jan 2020, 10:53
...but ISTR that on the C5 it should have involved using a drill bit of a particular size to pad out the space on one side of the woodruff key.
Found what I was looking for after I dug out my old Haynes manual for the C5. The floating pulley wasn't fitted until about March 2002 and this method thyerefore doesn't apply to the earlier 2.0 HDi. It also doesn't apply to the later DOHC engine AFAICS nor the 1.6 HDi.
Scan_20200117d.jpg
BX
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Re: Citroen quasi adjustable crankshaft sprocket

Post by BX »

The sprocket can move on the crank due to the wide slot. This allows for inaccuracies in the belt, idler pulleys etc. When the crank and cam are locked with the pins they are accurately timed with each other. Tightening the pulley in place locks the sprocket to the crankshaft maintaining this timing relationship. The key is only there to prevent the timing moving far enough to cause damage should the sprocket not be clamped tight enough by the pulley. In short the sprocket is located on the crank by the belt then locked in position by the pulley and you do not have to worry about it being centred. Any method of locking it centrally in the slot reduces the accuracy of the timing.
Some other vehicles have a vernier adjustment on the camshaft pulley. This is just a more difficult method of achieving the same thing.
On many vehicles both the camshaft and crankshaft sprockets are permanently keyed in position and the engine just functions with possibly less accurate timing. Why they bothered with this I don't know. The engines without these arrangements work just fine.
With regards to the Haynes instructions, the 2mm rod is only used in the initial tensioning. Afterwards the belt determines the location of the pulley.