Removal of cam chain tensioner (2.8 30V) with timing belt in place?

[Gecko Asiks]

Hi guys, I'm part way through replacing my cam seals, chain tensioner seals/gaskets, cam end plugs and VC gaskets on my 2.8 30V, but I've run aground. I started replacing the chain tensioner gasket and half moon seal using the 'lift and tuck' method on bank 2. Having compressed the tensioner and lifted it up and got the old gasket out, the small oil screen/filter/strainer that is seated on the under side of the tensioner (for the tensioner's high pressure oil feed) has fallen out while I was cleaning the gap of all the old gunk

At a time like this the word luck doesn't really come to mind , however I figure somehow it's a good thing I found it and it didn't drop inside the head. Problem is I now can't get it back in There just isn't enough access to do that with the lift and tuck method.

Having mucked around with this now for a while, I'm starting to think I might just be stuffed. I have the timing belt in place and don't have the required tools (or knowledge) to remove it, so a couple of questions with that in mind.

1. Can I remove the inlet cam (bank 2, US drivers side) and also the chain tensioner to replace the tiny oil screen under the tensioner, leaving the exhaust cam in place?

2. If yes, how? I have removed all the cam caps on the inlet cam (US drivers side) and the cam comes loose but I don't seem to be able to get it out because the cam chain tensioner can only raise a small amount until it gets jammed under the rear half of the timing belt cover. This blocks the cam cog and cam from coming up high enough to lift out the cam. Well that's what happened when I tried?

Any constructive help/tips will be really, really sweet, 'cos I'm kinda sweating on this one.

Cheers. M

[rollerton]

Wow. Theoretically you can do it, and I think it's been done. Something tells me that the amount of headache that you'd give yourself would be more than if you just bit the bullet and put it in service position to the point of at least being able to de-tension the timing belt. You don't need any special tools, ...the cam-lock bar is nice, but not absolutely required. It really should be about 1.5 hours at most to put in service position, then you can fix your problem, then about the same or maybe 2 hrs to get back together.
But as for sneaking it out as-is, ...which part of the TB cover is the CCT hitting? I thought you could remove all of the stuff around it, but maybe not on bank 2?

[034Motorsport]

^^^ Exactly. Just redo the timing belt.

If your timing belt is set and good and you know everything is good, rotate the engine around a couple times and then get the crank cog lined up with the factory tick, and then mark the crap out of your belt, cam gears, and your cam covers. With 6-7 marks, you'll be able to easily get it back in position.

You do not need the camlock bar so long as everything is timed already, then marked, then removed.

When reinstalling the belt, you'll likely find that without the cam bar, you'll need to skip a tooth so that when you release the hydraulic tensioner, it lines all the marks back up. Cam lock bar allows you to loosen the cam gears.

[Audi_Tech]

Mark a tooth on the intake camshaft sprocket and the chain rollers on either side of the sprocket as well as the same for the exhaust cam. Pull the intake camshaft out and you should have enough slack in the chain with the cam out to pull the tensioner out.

Torque the cam caps to 10Nm or 88 in. lbs. from the outside in staggering as you go. Double check your painted timing marks as well as the notched camshaft marks to the cam bearing bridge. I don't recall the number of chain rollers inbetween the cams to count to triple check your timing. Hollar if need be and I'll look 'em up.

[Gecko Asiks]

WOW. Bit of a journey this job. I've just wound up for the night (it's 12.30am) after working on it after I got home from work. I wasn't able to get the inlet cam out, but even if I could've, the chain tensioner wasn't going to come out because of the timing belt cover (I'll elaborate when I get time). Because of this I revisited attempting to get the tiny oil strainer back in with the chain tensioner in place. After much fiddling, and spending at least an hour finding the strainer again after it dropped down inside the timing belt covers (yeah I know, go figure), I did manage to get it back in (insert loud applause), and the new chain tensioner gasket and half moon seal as well. So we're back on track.

I did have to take the electrical sensor off of the chain tensioner, so if anyone can throw me the torque value for the two tiny torx head bolts that hold it on that'd be sweet? Or if you reckon just hand tight (they are tiny little bolts/screws), let know too?

Cheers guys. M

[Audi_Tech]

Hand tight will suffice.

Edit: I now realize that you're doing this on bank two (front of the motor) hence the camshaft belt guard in the way.

[Gecko Asiks]

Hand tight will suffice.

Cheers.

Edit: I now realize that you're doing this on bank two (front of the motor) hence the camshaft belt guard in the way.

Yes - correct. The tensioner was not coming out any which way with that timing belt cover/guard still on the front of the block. It has a weird profile (for no apparent reason) that angles over the top of the chain tensioner, meaning that tensioner will only come out with the timing belt off.

[pohsib]

What if you losened the bolts that hold the cover on? Would there be enough room to maneuver the tensioner out?

[Gecko Asiks]

While I'm doing all these seals/gaskets, is it OK to remove the the cam cap closest to the timing belt cog on the exhaust cams to clean the mating surfaces and renew the RTV silicon sealer? Obviously I'll be exposing the front cam seal even though I won't be changing that seal (as the timing belt is still in place, and it was changed last year with the timing belt).

Removing that cam cap won't mess up the fit or seal of that cam seal will it? Or is it best to leave it alone? I'm just thinking of eliminating another possible area for things to leak (the RTV sealant) while I've got access with the valve covers off.

Cheers. M

[Gecko Asiks]

...which part of the TB cover is the CCT hitting? I thought you could remove all of the stuff around it, but maybe not on bank 2?

The rear half of the timing belt cover/guard on the front of the block (bank 2) has some weird arse profile (for no apparent reason) that angles over the top of the chain tensioner, meaning that tensioner will only come out with the timing belt off. Next time you get a look at a 2.8 engine bay, check it out. It's got to be one of the strangest bits of engineering I've seen.

[Gecko Asiks]

What if you losened the bolts that hold the cover on? Would there be enough room to maneuver the tensioner out?

No. If you could loosen the cover, there's not enough room to pull it forward to get it clear of the tensioner. Plus, from what I know most of the bolts holding that rear part of the cover on are set behind the timing belt sprocket, so you'd have to remove the sprocket, which normally means service position, cam lock bar, remove timing belt, etc, etc...

[Gecko Asiks]

And how long does RTV have to cure before you can run the engine?

[Audi_Tech]

If it's not leaking then I would leave it alone personally. If you do take it loose I would throw a lil RTV between the seal and bearing cap just to be safe. By the time you re-assemble everything the RTV will have setup.

[Gecko Asiks]

If it's not leaking then I would leave it alone personally. If you do take it loose I would throw a lil RTV between the seal and bearing cap just to be safe. By the time you re-assemble everything the RTV will have setup.

I had a good look and it was leaking around the cap bolts, so I decided to take it off. I realised then there was no RTV underneath - hence the leak. It's amazing that oil could escape it's way up the bolt thread! All good now though.

Thanks for everyone's input and advice on removing the timing belt. Luckily I didn't have to go that far (and honestly I would've been out of my depth). I was lucky I was able to pop the chain tensioner up as high as possible, which gave me a good 10mm clearance to get the tiny oil strainer back in. I ended up making a small tool, almost like a long and very narrow spatula, to which I held the oil strainer in place on the end with a tiny amount of double sided tape. This made sure it stayed in place while I fiddled it upwards and into place. Once seated, I simply pulled the spatula out sideways, leaving the strainer recessed in it's seat. To keep it there until I'd fitted the new tensioner seal and gasket, I'd applied a small amount of Vaseline to the plastic outer edge of the strainer, simply to give it a bit of 'stick'.

In the end I was pretty lucky, however all the mucking around did mean I only got the bank 2 seals done.

Bank 1 is on the agenda for this weekend, and this time, with no timing belt cover to get in the way, I'll attempt to slip the inlet cam and chain tensioner out altogether so there's no repeat of losing that pesky oil strainer. Bit of a worrying thought to think that it could've oh so easily ended up inside the head.