DX Won't idle after cambelt change

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DX Won't idle after cambelt change

Postby bmouthboyo » 06 Jan 2018, 22:09

Hi Guys,

Bit of a long one but best to be thorough and I would really appreciate any help you could give.

I have a Kjet 1.8 DX engine in my VW T25 Campervan which has been running reasonably well until today.

I decided to do a cambelt change as I have no idea of its past and when it was last done as well as wanting swapping the cork rocker cover gasket for a rubber one to stop a slight oil leak which I think is compounded by the angle the engine has to be installed into these campervans.

So I followed the guides on here and all seemed to go well. I noticed the immediate pulley punch mark was not lined up exactly with the crank pulley line so adjusted this to where it should be and after a nightmare getting all pulleys to stay in position whilst fitting the belt ended up with the following alignement:

Cam Sprocket:


Lined it up with the head. Not sure if this is right or should be with gasket on when aligned?

Intermediate Sprocket:


The white mark just above is where it previously was in relation to the crank pulley, looked a tooth out.



Bit unsure what part of the wide contact should be lined up with the dizzy body notch at TDC.

Flywheel Mark:


Was actually slightly to the right originally but it lined up as in the image above once I had the crank and intermediate marks aligned

So I started her up and... ran for about a minute, slightly rough then would not idle without high revs. I tried turning the dizzy left and right slightly but it did not stop it from stalling.

I tried adjusting the fuel mixture on the metering head but this did not seem to help either.

To make matters worse the rocker cover was leaking worse than before above the intake manifold. I tried tightening the 8 nuts but 2 threaded, one of which I now need to use a stud extractor as the nut is rotating freely. [DISAPPOINTED FACE] Not really sure how I can stop this leak as I hoped the newer rubber gaskets would sort the issue.

At the end of play:
- Couldn't get it to idle without revs
- Rocker cover leaking more than before

So really I am looking for some advice on where to start with getting it to run well again. I have a timing light I have no experience using but no way of seeing the revs. I was hoping to get it idling well at 0deg TDC then set it up from there.

1) From my images, does it look like I have the timing marks setup / aligned correctly?
2) What is the best approach to getting it timed correctly?
3) What is the order of adjustments? Fuel mixture, dizzy or idle screw?
4) Any ideas on how I can stop the rocker cover leaking?
5) I seem to have a wider distributor rotor arm. What part of it should be lined up with the notch?
6) When lining up the cam sprocket punch mark with the head should I have the gasket on or straight with the flat aluminium the gasket sits onto?

Thanks in advanced for any advice [THUMBS UP SIGN]
1983 Autosleeper Trooper - 1.8 Gti Conversion
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Re: DX Won't idle after cambelt change

Postby garyd » 17 Jan 2018, 16:25

I don't know if you have got this sorted yet or not. However, my recent similar experience my be of help. I have the later AGG engine in my Syncro and, like you, did a cambelt change and found it was not running properly. The AGG has timing marks on the face of each of the three pulleys. The cam pulley aligns with a cast arrow on the end of the rocker cover and the other two come together as in your 2nd photo. I agree, getting the belt on, and all three pulleys properly aligned is a difficult job. When mine would not run properly I did some further research and discovered the dizzy timing mark. I found this slightly mis-aligned. Analysis - intermediate pulley one tooth out!

I tried to adjust this by rotating the dizzy body but found it was seized in the block. Two weeks of regular applications of Plus Gas failed to free it so I had to go back to the belt!

One thing I thought of during this period really helped me get the belt right the second time. Before slackening the belt tensioner I fitted small cable ties through the pulleys & across the belt & rim of the cam & crank pulleys to prevent the belt disengaging from the teeth. On the cam pulley, the cable ties was fitted at the six o'clock position so that, once the tensioner was removed, the pulley could be rotated (clockwise) to bring all the belt slack into the top run and the intermediate pulley. I also Tippex'd a mark on the belt and the pulley to ensure I moved it only one tooth. With that done I was able to confirm that the rotor arm now properly aligned with the TDC notch.

The key thing is that it now runs properly again!

Quote 'The white mark just above is where it previously was in relation to the crank pulley, looked a tooth out.' I think this is the key statement. It ran properly on the old mark and you changed it to a new position. On mine the intermediate pulley mark is about 90* out but putting it back where it was (rather than where it should have been) is the key.

Another tip I've been given is, before starting to remove the old belt, cut it down it's centre-line and remove only half the width, thus keeping the pulleys all in the same relative position. You'd probably have to slacken the belt slightly to achieve this. Then, slip the new belt half-way onto the pulleys, cut & remove the second part of the old belt and push the new one right on. You have still got to carefully change the tensioner pulley though without letting anything slip. Time for cable ties through the pulleys again perhaps?

Hope this helps.

1990 Transporter syncro camper
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