Cam chain tensioners/pads removal and replacement guide

[Shoppinit]

I have never seen an engine bay that would benefit more from an R8 coolant cap.

[Classik]

I have never seen an engine bay that would benefit more from an R8 coolant cap.

[Jayjay101]

I have never seen an engine bay that would benefit more from an R8 coolant cap.

Got one coming from Santa ready for the new year mate


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[Classik]

Just made some measurements yesterday following the replacement of the chains and tensioners pads, and I'm not so happy with the results : on group measurements 93 (long term phase or whatever it's called in English): I read - 1 on Bank 1 and - 5 on Bank 2. From memory it's still within specs, and the engine feels and idles very well, however I would have liked the numbers to look better.
Well, should I worry? And if yes what should be done to fix this?

Thanks!

[Shoppinit]

The acceptable range is between +3 and -1. You’re quite a long way out on bank 2.

Could you have miscounted the chainlinks? The gap is not the same on bank 1 and 2.

[Classik]

Ooops, no good news then. Need to check with the mechanic who did the job, but yeah I heard about the gap difference between bank 1&2 for those chains. Hopefully he made quite a few photos which could help to identify the problem.

[Shoppinit]

Could be a Tippex special job on the cam belt. You see that kind of timing error there.

[Mɐʇʇ]

I found there is some extra finesse possible on the cambelt. Basically, the clearance between teeth on the sprockets and belt isn't zero - so there's a bit of backlash possible.

In short, once you have the belt on, the tensioners taking the load and the the cam sprocket bolts up finger tight, but the brace still on you can just nudge the sprockets to preload the belt the right way. Then tighten up a bit, crank it over a turn or 2 by hand and recheck. Without doing this, I found that cranking it over a couple of times caused the belt to settle enough that I couldn't then get the brace back on - but doing this (a couple of goes), it came back 100% perfect.

[Mɐʇʇ]

Oh, the other thing I found is it's all a right ballache doing the belt with the lock carrier in place - so TBH I just pull it off and accept that I'll need to recharge the AC & refill fluids - but as part of a "major", that's par for the course anyway.

[Shoppinit]

I don’t think he’ll be able to make up 4 degrees doing it that way. I think he’ll have to lock up the cam and crank and redo the tension. Assuming it’s the timing, that is.

[Classik]

If it can help: just talked to the mechanic and he said he checked 3 times the chains timing which is indeed different between banks. He also mentionned he did clean the tensioners (that have not been changed, just the pads) thoroughly and checked the springs, so normally issue there in his opinion.

As far as the cam belt is concerned, he's done it many times with the special bar tool, and again he is pretty sure the alignment is good, although it would be worth checking whether the tensioners/springs (of the timing belt kit of course, not the cam chains) have not been tighten too much.

But as Shoppinit rightly pointed out, could that explain those 4 degrees difference? And if not what could cause this? Ta!

[Classik]

And thanks for the above tips ^^ I'll definetely check this with him.

[Mɐʇʇ]

@Shopp - Sorry - that was what I meant - everything locked up as per the procedure, but just putting a bit of preload on the belt the right way. But you're also right, defo not 5 degrees. Maybe 1.

[Shoppinit]

Have you checked how much dephasing you are getting? Might be a seized dephaser.

[Classik]

Not sure I understand (sorry for my English). Do you mean : what are thg extreme dephasing values I get under different engine loads? I suppose you are talking about the short term values (Measuring block 90?) ? Can't translate 'Seized dephaser', sorry.