That 1.8t rattle on cold start

[Ovid]

I decided to investigate this problem at last along with cam/crank correlation DTC and this is the cause.

As we can see the timing is out ,now how many links (rollers) do you count between teeth on camgears , this is what it should be.

 

[Ovid]

Here's pic which shows rollers between cam teeth

Now it could be me getting old and my eyes playing tricks but i count 17 rollers.

 

[Ovid]

Anyone concur ?

 

[Mike B]

Not certain but seems to be 16.Wouldnt 17 be more obvious?I thought rattle on these was likely to be the pick up pipe problem

 

[Ovid]

No mike i ran it with rocker cover off and you can see chain rattle against guides, i keep checking and it seems to be seventeen if you go by where rosstech say rollers sit. I suspect the bottom chain adjuster guide is at fault allowing play in chain on initial crank until oil pressure gets up and thats why timing goes out, it is very common on 1.8t,s and everytime i work on 1 with the rattle it turns out to be the edges of the bottom guide have snapped off and top adjuster has to take up slack which is why they rattle. Ive lost count of how many sumps ive pulled off only to find even with new oil pump you still have rattle until you renew adjuster. This thread is about teaching ppl, i already knew the answer but thought id educate everyone , by posing the question above they now know what to look for

Once adjuster is off i will post pics and show what happens.

Oh nearly forgot..................this is good news for most of you cuz its much easier to remove and replace adjuster than it is oil pump.

Thanks for replying and taking part in todays lesson mike. lol

 

[Mike B]

Thanks all new to me.We have a1.8t Bora and my son and his mates haveS3s so have seen the mess in their sumps but never heard about chain problems before.Is it mileage or servicing related or just another quality or design gremlin?

 

[Ovid]

They seem to start the rattle from 80k onwards and when you consider the chain drags across the adjuster guides constantly (1 on top and 1 on bottom) its inevitable it will fail, the edges of the guides break off(made of plastic) once they break the chain slackens and the adjuster pistons have to try and take the slack. im sure somewhere in audis service schedule there must be a point of replacing the adjuster its destined to fail and with bad oil pickup the whole process is accelerated , not the best idea ive ever seen.!

 

[Broken Byzan]

looks like 16 to me. The tensioner needs to be all up to correctly count the rollers

 

[Mike B]

Again thanks for the tip.Ours are well into their 2nd 80ks so will bear this in mind

 

[Ovid]

Exhibit A as you can see the bottom guide had sure enough snapped the corners off and allowed slack in chain which sent cam timing ape and caused annoying rattle on cold start.

Now there is 16 teeth before there was 17 .