d2noob

I'm in the need of doing a timing belt job soon. This will be for the 40v engine. What are all the parts that I need to buy for the timing belt service and what good quality brand? Also what are all the timing belt job tools do I need to buy?

Kneale Brownson

See: https://www.blauparts.com/audi_timin...elt_tools.html

d2noob

Thanks for the link. Holy crap is the 3240 and 3241 tools expensive! Also the T40001 tool is expensive! Would a generic camshaft sprocket puller work? The others isn't bad price wise.

2001 S8

I would advise caution on Blauparts timing belt kits, not their tools. Several D2 posters have complained about the quality/durability of their parts; especially with their belts. I would recommend going with something from ECS Tuning or FCP Euro. Make sure the belt is made by Contitech. (Continental)

FCP: https://www.ecstuning.com/b-assemble...ate/077198507/

ECS: https://www.ecstuning.com/b-assemble...ate/077198507/

Good luck.

d2noob

Thanks for the heads up. Just a FYI your FCP link is ECS. I do usually buy Contitech timing belt. I'm a little worried about the tensioner lever/roller because I've never heard of the brand NTN.

BrianC72gt

And what's the consensus on the water pump impeller...plastic or metal and brands. I forget all this stuff until I need it the next time. Oh, yeah, use an OEM thermostat.

The two must have tools are the crank lock and the cam bar, I popped my sprockets lose with a flywheel/gear puller and a little vibration with a light tap from the point of a body hammer. Pressure and vibration..pop.

And if the timing was set right the last time, you don't absolutely have to free the cam sprockets from their tapered shafts.

jfrahm

I've done the job with no tools, just slapping a new belt on. It's not super easy to balance the belt tension across the banks without the tools and the cam sprockets freed up but it can be done.
Some people who use the tools then go back in and fine tune the cam timing based on the readings in VCDS so that's an option.

I honestly do not know what is more correct, the locking tools or the cam phasing as per VCDS.

BrianC72gt

I've done timing belts commando style as well, but you really have to know what you are doing: feed the crank cog first then work your way backwards around the pull side of the belt and feed the slack into the tensioner. The trick is to turn each cam slightly ahead of time to ease getting the belt on then turn it back until the belt is taut and confirm timing is right, same on the other bank, then feed all the tension into the tensioner and check that flywheel and cam marks are all good. Those little black spring binder clips are also handy if you're not an octopus.

In chasing fuel trim, is it the passenger's bank (U.S. car, LHD) that needs adjusting or both? Do you mark the cam relative to the cog before popping the cog loose? How do you hold the cam steady from jumping ahead or back under valve spring pressure on the cam ramps?

jfrahm

Just like a 928, if you to the job with the crank 45 degrees ATDC the engine will sit happily with the cams not trying to spring backwards or forwards. I think that's correct, made some notes in a thread when I did this last time. It does not take much movement at the cams (half speed compared to the crank) to get to a spot like this and you can tell if the cams are under spring tension easily enough. With the plugs out it's pretty obvious when the motor is in a happy/safe spot.

You do have to set the timing such that when the tensioner pulls the belt slack it pulls you into time, but to facilitate this you can also mark the belts (old and new) and the sprockets and count teeth and set it back the way it was. Good enough for most cars. When the pin is pulled and the tension comes in the cams turn different amounts also, so it really looks off until tension comes in and pulls it correct.

It does not make a lot of sense to me to time the engine perfectly with a brand new belt as the belt will wear in to match the cogs in 500 miles and more slack will be pulled. On cars with static tensioners it's a bit spooky how loose a new timing belt gets in that timeframe. If I do it again I might set the other cam belt idler to anticipate some movement of the tensioner, maybe 1/3 a belt tooth's worth of movement by the tensioner as the belt settles in. I looked at my A8 with maybe 70K on the belt and the cam timing was acceptable but looked like it'd be right back in as-new time if I could move that idler opposite the tensioner a bit and back off the extended tensioner likewise. Which makes sense.

The tools are cheap enough nowadays that if I was doing the belt on my S8 I'd get the cam bar since it makes it easy to even out the belt tension. Plus it'd need front engine seals so it's all coming apart anyway.

With no valve spring force trying to rotate the cams simple marking of the sprocket relative to the cam should work for fine tuning.

d2noob

What is the timing belt service interval for these cars?