Bit of a techie question this one but here goes..., Just changed the cambelt on my 1987 GTi 8v and was setting up the timing marks as per the Haynes manual and can't seem to work it out. I changed the cambelt on my previous Mk2 GTi several times with no problems, but on this one the intermediate shaft has 2 marks on it, and lining up the crankshaft sprocket circular mark with the intermediate shaft with the camshaft no.1 valve closed and the camshaft mark flush with the top of the head (as per the maunual) resulted in a car that would not start...
Is there a way to statically set up the timing independent of the crank and intermediate shaft marks? ie set the no.1 valve to closed with the camshaft sprocket mark flush with the head, maybe set the crank to TDC using the flywheel mark and then turn the intermadiate shaft to some position which I don't know?? ? The crank/intermediate sprocket marks appear incorrect and a static way of setting up should at least get the car running, then I could tweak it dynamically using the usual strobe method... Any help appreciated
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Ian,
A little like the answer to the Peugeot timing belt query below....if the engine was running OK before then it will if the timing marks are set by the book. I wonder if you set them to this position before removing the belt? If so surely there was no need to rotate anything and they should be in the same position with the new belt.
I would guess your car has a notch in the crank pulley that you line up with a punch mark on one tooth of the intermediate sprocket. At the same time the mark on the back of the camshaft pulley should be level with the valve cover gasket face, this when the No.1 cylinder cam lobes are both pointing a little above the horizontal (ie. valves closed).
Some VWs have a mark on the front of the cam pulley which is the easiest to see, this is usually not the correct mark for earlier engines. Your engine code would confirm this.
David W
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Ian, IIRC the intermediate shaft just drives the distributor. The distributor has a line etched on the upper edge of the case to show when the rotor arm is pointing to cylinder no. 1 so you could use this to check whether the diz and intermediate shaft are in sync.
I suppose it might be possible that the intermediate shaft had been installed out of sync by a previous owner and the mark on the distributer was used to statically set the timing even tho the intermediate shaft marks are out ?
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I have personal experience of many Golfs where lining up the timing marks on the dogshaft has put the ignition timing waaaay out. This is due to careless practise causing the dogshaft to be moved out of alignment whilst fitting the belt. I now align cam and crank marks and check the orientation of the distributor alignment marks as per the previous post. If all correct there is a small notch on the blade of the rotor which will align with a line on the edge of the diz. The theory being that once you have aligned the flywheel mark the cam mark should align (+/- the stretch in the belt)and the diz marks should align.
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Many Thanks for the replies, a few more questions:
1) if the crank is rotated such that the timing mark (in the recess on top of the clutch housing) is at TDC, should the crank pulley mark be in the correct position (if it should then it aint!)
2) the camshaft TDC centrepunch mark - should this be flush with the top of the head at the forward edge of the head or 180 degrees out nearest to the driver?
3) my intermediate shaft has at least 2 marks on it so it something has been previously played around with, as suggested I will try and align the rotorarm with the mark on the top of the distributor, the notch on the blade of the rotor that Andrew talks about, where is this notch? Is it down the centrline of the rotor (ie the centre of the brass contact area) or am I missing something?
thanks again
Ian
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Regarding the timing marks on the crank, I have fallen in the trap of using the notch and arrow on the front pulley, it is NOT ALWAYS TDC, always use the notch and pointer on the bellhousing. (unscrew the hexagonal plug for clearer view) If you have an aftermarket rotor without a notch in it use an imaginary line thro' the centre of the arm as you suggest, if all is correct it will pretty well line up.
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I'm interested that Andrew has found the makers timing marks out on some VWs. I happen to look after less VWs than other makes but have been lucky so far they've all timed by the book.
Having said that something I do with every car when I change a timing belt may help. I always turn the engine to set the timing to the makers marks before removing the belt. If there is any apparent error or conflict I double check before proceeding, mostly an extra turn of the crankshaft will bring things into line.
However if one mark won't line up and the car was otherwise running fine I will consider leaving it at that *odd* position.
Most importantly I never ever take the belt off before I've marked the wheels/sprockets with blobs of white paint corresponding to matching blobs on adj' components. This means I never have to rely on remembering where everything was before I started the job.....or an indistinct makers mark. For this I always have a white touch-up pencil handy.
Perhaps the best engines, like the Citroen diesels, are the ones where a set of timing pins are inserted before taking off the old belt then you know nothing has moved when you fit the replacement and it *will* run afterwards.
David W
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Sorry DW I think I may have misled you slightly. What I meant to say was that previosly to my looking at the car someone has allowed the dogshaft to move out of position and rather than correct it to where the manufacturer intended has simply moved the distributor to compensate. Then when you line up all the marks the diz is apparently out of position....
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thanks for your help guys, car now running sweetly with the crankshaft and camshaft marks bearing to relation to where I (or the manual) expected them to be... Yes I should have marked up the positions myself before removing the old belt but I had the head off and the car got moved in gear which moved the crankshaft...
Anyway I ignored the marks, and as advised set the flywheel to TDC, the No.1 cylinder camchaft lobes to both valves closed (with the inlet and exhaust lobes in the same symetrical closed position) and set the intermediate shaft such that the rotorarm was over the distributor notch and deep joy it ran, just the usual tweak with the strobe all is fine. So yes mark up positions before removing the old belt and don't always believe the pulley marks and all will be well!
Ian
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Good news Ian. I think DW's touch-up pencil hint ought to go in the Top Tips thread
Phil
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