I am in the process of replacing the intake camshaft drive chain and tensioner pads but the front sprocket is proving to be stubborn. Any ideas on ways of removing the cam sprocket to access the rear cover mount bolt so that the front cam bearing and then camshafts can be taken out of the way?.

 

Take the Hall sensor off the back cover. This will allow a path to get a punch on the back of the sprocket. Gently tap it out.

 

I had the same issue and tapping and knocking did not help at all. I used a harmonic balancer puller in the way shown in the picture below:

 

On one of mile there was a bump on the camshaft from someone going overboard torquing the bolt. I had to stone it off later. Mark the positions of the three bolts on the adjustment holes before messing with them. It's also easy to break the tripod thing behind the sprocket if you try to force it off past resistance on the cam.

 

Thanks folks. The hall trigger is already out so I'll try the brass punch first. Cheers.

 

I'm about to tackle this problem on my s2 as the rear cam pulley cover looks about ready to disintegrate. I'm a little unsure about maintaining the timing when taking the pulley off the shaft. Since the pulley cover is different to the ones used on the 8v engines I got a little paranoid that I could mess up my valves if the removal process was also significantly different.

I'm hoping that the only important difference is that the Hall effect sensor is on the back of the cover and that if I put the three screws through the pulley and into the ignition rotor then they can still be safely removed and reinstalled without making any scribe marks across the pulley-shaft interface.

From what I gather the ignition rotor should slide off with the cam pulley, which is keyed to the shaft, so timing should be maintained. I got a bit confused in the Clark's write up when the author said you shouldn't need to make any scribe marks, but described making the marks anyway. Any clarification would be great, thanks

 

When I did my 87 S a few months ago I put the bolts back into the cam to retain the timing. This is actually what the factory manual mentions to do so not sure why Clarks Garage has you go through such a process.

Take the rotor off, replace the three bolts then take off the main center bolt. You can still mark if you want but as long as the three bolts are tight it won't move. I used a three armed gear puller to remove mine with no issues. There was no way it was coming off without it. Once it initially starts to move it doesn't take much force.

Chris

 

New aluminum covers are available from rennbay.. $500 but they don't degrade like the magnesium ones do.

 

Very easy. Just take 3 longer bolts like the ones on the ignition rotor and tighten the cam pulley to the triangle piece that sits behind it. Your timing will now be intact. Just slide the pulley off. Due to the woodruff key, the cam pulley is now locked in position in reference to the cam.

Good luck.

 

One bit of advice, when you reinstall the sprocket, put some anti-seize on the shaft. Fretting corrosion is common issue for sprockets mounted in this fashion and can make it difficult to get things apart later. I'd use the same anti-seize on all the shaft/sprocket interfaces on the front end of the engine. When I did my timing/balance belt and seals a couple of years ago I found a lot of these interfaces had brown patches indicative of fretting corrosion. This is what mine looked like.

 

Great, thanks everyone for the advice. It's a relief to see that it should be fairly straightforward!

 

I recommend using a puller of some kind, recommend strongly against whacking things with a drift. The cam sprocket can get stuck on pretty well with corrosion and age. Some heat on the cam sprocket center may also be helpful.

Use of anti-seize also something I agree with. For this kind of close tolerance, I like the Optimoly HT that Porsche sells, 000.043.004.00. It has a high, fine grained metal content, low lubricant content which appears (to my eye) to coat better and resist wiping when reassembling.