Special tools needed for doing the cam chain tensioner job?
 

I know that I will need these tools for the timing belt job eccentric pulley pin wrench, crankshaft locking lock pin, cam locking bar, camshaft sprocket puller, camshaft seal installer, camshaft seal extractor, belt tensioner pin. I would like to know if I will need any special tools when replacing the cam chain tensioners? I also will be installing new timing cam chains.

The tensioner has a special tool 3366 to compress it so you can get everything apart. New tensioners should come with this tool holding them together in transit, but its worth buying another one to remove the old tensioners as they are very cheap.

You'll also need a 5Nm torque wrench for the cam cap bolts. They are 5Nm + 90 degrees.

Tip: hit the top of each cam cap bolt with a hammer using the T30 torx tool as a drift before you try and remove them. They aren't tight, but they have so much stiction in the head it is very easy to strip the heads, snap the T30 tool etc. Hitting them lightly just cracks the stiction and then they come out easily +++

Be careful to mark up the cams and chain positions. If you are going to replace the chains I think you will have to completely remove both cams. I did anyhow. It makes reassembly less stressful.

There is a procedure for counting the number of links in the Bentley manual but I found it a little confusing. I found this way easier and as I say, less stressful because you know it will be as it was when it goes back. Simply lay the old and new chains side by side and replicate the marks.

Thanks for the info MikkiJayne and thanks for the tip spannerrash.

Next question, can the tensioners and chains be replaced with the cylinder heads on or do they need to be removed?

Can be done without removing the heads.

MikkiJayne did a whole video showing the procedure start to finish:

http://forum.a8parts.co.uk/showpost....0&postcount=73

Bear in mind I didn't change the chains then (I usually don't) and so I could do the job with the exhaust cams still in.

Also, I pointed out the stupid gauze filter in that post. I have subsequently learned that the gauze is actually the reason for tensioner failure as it breaks apart, goes through the tensioner and jams the startup pin. I now leave the gauze out, as it is coarser than the oil filter anyway. I'll take my chances with whatever comes through the oil supply, rather than guaranteeing failure when the gauze breaks up.

How would the process differ if i wanted to change the chain as well?

You have to pull both cams rather than just the inlets.

You really need to decide how far you want to go with this job. I work on my car as a hobby and so quite often do jobs that probably don't need doing and may return very little benefits. The timing chains being possibly one of these jobs. Replacing the chains will make the job a little more complex and time consuming with the additional risk of getting the timing wrong on Re-assembly.

When I did mine I did it as part of a whole load of work that I was doing at the time. I had the front of the car completely off and was doing the timing belt, water pump, oil cooler water leak etc all at the same time. Doing the chains only added a little extra time to my job but may be proportionally more to yours.

When I compared old chains to new I could not see any definitive difference between them. It maybe I changed them for no reason.

I do just simply have a mentality that "if I'm in there anyway" I may as well do it. It's not a cheap way to live.

Thanks for all the info/tips.

Is it really needed to install new cam chains? My S8 has close to 200,000 miles (321,868.8 km "google search"). I plan on keeping this car for awhile.

That's not an easy question to answer. I have never heard of the chains snapping but chains do wear and stretch over time. Personally, if I were spending the kind of money you are going to have to to replace the tensioners I would do the chains. This probably sounds obvious because that's exactly what I did.

If the extra work and time involved is a problem then I think I would take into account wether the chain slides had failed or not. Sometimes when the slides break up, the chain can end up running over the metal part of the tensioner grinding the tensioner away. If I saw any evidence of this, personally I would fit new chains.

At 200,000mls though, I would just do em.

When is your timing belt next due? Maybe you could do it all at the same time.

OK you convinced me to install new chains. I plan on doing the timing belt job at the same time.

Some reviews I've read about the special tool 3366 break while using it. Is this because of aftermarket version of the OEM tool? Or is it because of not using the tool correctly?

I would say because of not using the tool correctly - probably over-tightening it. The tensioner only compresses so far, and unless you've got a 200lb gorilla on the tools you can easily feel the change in torque on the screw as the tensioner bottoms out.

I've used the Laser Tools version and the cheap chinese ones and never had a problem.

This. It's the same tool as on a VW 1.8T. I've done the tensioner on a 1.8T a few times and the only time I ever broke one was because I wasn't paying enough attention and over-tightened it.

Ah, I had a feeling they broke because of improper use.