Cambelts -- A Warning

[KLB]

Originally posted by skodaw in this post
Hello Isaac

Yes we do mainly see the fault with VVT equipped 1.8T engines,although not exclusively.And even those which don't have VVT use very similar oil feed tensioners for the cam chain(being a dual cam engine - 1 cam driven direct off cambelt other by short chain link).
My own personal view is that it is this component that strains the belt - it only takes the oil pressure relief valve to stick and the tensioner's pressure against the chain will increase - this will then in turn increase the strain on the cambelt - hence stripped/seperated teeth - rather than snapped cambelts.

I will try and post some pictures to try and clarify these points.

Apologies for hi-jacking this thread - but I'm intrigued by your description of the VVT mechanism. I had assumed that both camshafts were driven by the same belt, with separate tensioners to change valve timing by altering the "phase" of the pulleys relative to each other. If one camshaft is driven by a belt, and the other is driven by a chain (from the first camshaft?), I can't see how the valve timing can be altered.

[DGW]

Had a quick look at ETKA. A chain is shown linking both cams. I live and learn.

[skodaw]

Mike

No apologies required.When oil pressure is applied to the tensioner - this effectively shortens then chain there by adjusting the cam timing -- the cam being adjusted has fee movement as it is only secured by then chain - whereas the other cam is held in plaice by the cambelt(hence the strain)
hope this helps - as I said before,if I can remember to take my camera to work(forgot today) and I get time I will take and post some photo's.

[skodaw]

As promised(hopefully if I can get it to work :o ) some photo's of damaged S3 head.







Hope the pictures help clarify what level of damage can be done - and this one is quite light.Also shows how VVT system adjusts -- whilst inlet cam is held by belt - exhaust cam is moved by increase in tension against chain - which effectively shortens chain causing cam to rotate.

[mellowyellow]

Had a look in the 2003 Autodata Timing Belt book today for the 1.8T , it says to check at 60,000 and then to check every 20,000 for wear and if OK to change at 120,000 ...............sounds too long to me as I'm sure it does to others .............BTW the time for changing the cambelt is given as 2.20 hours , so it wouldn't cost a fortune to have it changed .

[skodaw]

That's my point - if only people were more aware I don't think anyone would hesitate,even out the relatively high Labour rates for Audi - you are only looking at around £300 -- not bad compared to a minimum repair of approx £1,500 ,or more likely of £2,000

Try telling that to some of my customers tho....

[mannyo]

The pics are not displaying, because we dont have permission to access them, if you email them to me I can link to them. send them to manny.otero@ntlworld.com . or alternatively you can attach the pic to a post, one pic per post.

[TaviaRS]

Mine will be being changed again in about another 10,000 miles. Whne we looked at the last one it did have some wear and I for one wouldn't want to have gonme to the 120k interval before changing it

[DGW]

Jon, two questions. When did you have the last one done? And do you think that members will know that your car has done 100,000+ miles?

[TaviaRS]

I had the first one changed at 59979 miles. This one will be done at or about 120,000

[skodaw]

Sorry about the photo's guys - have mailed them to Manny - it works on my PC - but then of course it's my PC - so it would wouldn't it - DOH!

[mannyo]

Ok,

got the pics now,

Looks pretty bad.

[BAAHEED]

If as you say Dave the belt is being stripped rather than failing due to snapping or tearing it would suggest to me that there was another problem causing this failure e.g Water pump ceasing, idler ceasing or tensioner ceasing whatever it seems to me that its more VAG's problem if such a failure occurs under the warranty period on a car serviced as per the manufacturers recommendations by a franchised dealer.

I do however whole heartedly agree with your advice on changing the belt prematurely.

[skodaw]

There are a couple of reason's why the belts strip -- the most common appears to be waterpump failure -- the impellor is made of a plastic material -- and some times when they fail they break up - causing the pump to jam -- and therfore the teeth to strip.

The other is less common - the VVT tensioner can over tension - and snap the chain -- which then usually raps itself around of of the cams - causing it to stop dead -- and strip the teeth.

[MeatballTurbo]

Skoda always used Chains until the use of the VW based 16v engines.

And they didn't use any additional tensioners, they just rattled pretty much from go until about 60k, but never heard of one breaking.

My old Saab 900 is Chain timed, , and I really do need to sort out a revised type chain tensioner to prolong the life of the chain beyond it's existing 126k, and save myself a £400 chain replacement bill, or a new head if it finally does go.

[Amanda Hugnkiss]

Anyone know the cambelt interval on the 2.8 V6? I assume its the same for Audi/VW and Skoda. Would have said VAG but SEAT don't have a 2.8 V6

[Dutch4x4]

Originally posted by Amanda Hugnkiss in this post
Would have said VAG but SEAT don't have a 2.8 V6

Yes, they do!

How about the Seat Leon 2.8 V6 Topsport 4, formerly known as the Seat Leon 2.8 V6 Cupra 4?

[Amanda Hugnkiss]

Sorry, I should have been more specific (unlike the lovely Denis not to pick me up on that) but they don't have one in the UK, officially.

Oh and happy birthday!

[Dutch4x4]

Ah, but you do have a vRS with climate control and 17", so the UK isn't always getting a raw deal...

Originally posted by Amanda Hugnkiss in this post
Oh and happy birthday!

Thanks and

[skodaw]

Amanda,

The cambelt change interval for the 2.8V6 engine is 80,000 miles.Quite often the water pump will also require replacement at this mileage -- due to signs of leaking,it is a good time to change even if not leaking as it is a huge job to do seperately!