Some good news about camshaft wear...

[Paul_RN]

Assuming cam wear is spotted, how much is it to replace the cams at a specialist?

[mikeyquattro]

up to £2500....

[missmouse]

sorry to seem dim here guys, but maybe someone could explain to me why the MAF can have any effect on the wear of the camshaft?
I can easily understand poor oil changes or blasting the car from cold or poor materials ( unlikely Id say) but MAF problems?
speak to me.

[missmouse]

You could spend all day moaning about it and discussing the issue of cam wear, but the fact is it will happen one day to your car, why dont you save yourselves a load of cash on followers and get them done BEFORE they destroy themselves??

Surely that makes more sense? Preventative maintainence is better, thats why you have your car serviced every year right?

Yes Audi have messed up with the cams, but they wont give a damn about it on a 8-9 year old car IMO.

I agree with your sentiment Tom, however no-one is going to shell out for new cams on the basis that they "might" wear out.

Mine only needed one new follower out of 30 anyway!

been a mechanic for 35 years & ive never heard of anyone replacing a camshaft without replacing all the followers!
BTW can anyone tell me if the followers on this engine are hydraulic or shims?

[stumpyrs4]

up to £2500....

?!!!

Apparently 2-3hrs to check them out, and if need changing a further 7hrs = 10hrs labour = c£600+VAT

Are the camshafts and gaskets themselves therefore that expensive?!

[mikeyquattro]

depends on what you have to get. Camshafts, followers, chains, tensioners, etc......

[Norrs2]

sorry to seem dim here guys, but maybe someone could explain to me why the MAF can have any effect on the wear of the camshaft?
I can easily understand poor oil changes or blasting the car from cold or poor materials ( unlikely Id say) but MAF problems?
speak to me.

Must admit, although no expert, this one has me stumpted too.

In addition, if there is no apparent wear, but a couple of small "pits", does this also warrant changing the Cams??

[Spunbigendbearing]

A knackered MAF will cause a lean mixture,so higher EGT's and more heat at the cams/followers etc.,thus probably higher chance of wear.

[musty1]

You could spend all day moaning about it and discussing the issue of cam wear, but the fact is it will happen one day to your car, why dont you save yourselves a load of cash on followers and get them done BEFORE they destroy themselves??

Surely that makes more sense? Preventative maintainence is better, thats why you have your car serviced every year right?

Yes Audi have messed up with the cams, but they wont give a damn about it on a 8-9 year old car IMO.

I agree with your sentiment Tom, however no-one is going to shell out for new cams on the basis that they "might" wear out.

Mine only needed one new follower out of 30 anyway!

been a mechanic for 35 years & ive never heard of anyone replacing a camshaft without replacing all the followers!
BTW can anyone tell me if the followers on this engine are hydraulic or shims?

They are Hydraulic, sometimes the cam ware can be on only two lobes so only need to change the followers, sometimes if you catch on the early stages and the lobe is sliglty flaterned you can get away with no damage to the follower.

[Dippy]

Just read this thread, and even though it's been going for months, I'm a bit surprised that I might have relevant information (although that remains to be seen depending on the responses).

Firstly RS4 vs S4. Only going by memory, but I'm 99% sure that the RS4 has different cam profiles than the S4. I also thought that the cams, like other components were supposed to have been strengthened. However what is for certain is that they are different and so commonality between the two models has to be ruled out.

Secondly longlife oil/servicing. I know the S4 service recommendations, and I think I know the RS4's too. The difference was that Audi required the same oil for longlife as for timed servicing. (On the S4 even semi-synth was permitted for timed servicing). The RS4 has to use oil to VAG 503.1 (or something like that) which meant that it had to be fully synth (e.g. Mobil 1). The only difference between longlife and timed is that for longlife the oil viscosity sensor is used to determine when the oil must be changed. If it is accepted that low viscosity is a contributor to cam wear then it means that either audi got the setting wrong or longlife servicing is not relevant.

However finally is the most relevant information. Many years back a German tuning house (can't remember which) published an advisory note for S4 owners. It dealt with premature cam wear and it provided a simple conclusion and recommendation: The S4 should not be run on the 0W30 oil that Audi recommended, but an oil with a higher viscosity such as 0W40 or 10W40.

On reading this I made the switch straight away: It was easy to do because I could not easily get 0W30 oil (such as the Castrol) whereas 0W40 (or is it 10W40?) Mobil 1 is readily available.

Now I believe that the 10W40 oil makes the engine run slightly hotter (practical experience), but the viscosity is still higher than 0W30 at the operating temperature. It makes sense that this would protect the cams more. Additionally I read that a bad MAF can contribute to the cam wear? If so, I understand that the preferred failure mode of a MAF is to read low (due to contamination), so the ECU thinks there is less air than reality and so injects less fuel. My understanding is that lean means hotter, and of course this means the oil viscosity is lower.

So there you have it. I'm open to be corrected if I am wrong about anything.

[EuroSag]

@Dippy, very interesting and something that I would tend to agree with in principle.

I have a Lambo Murcielago and had a similar issue in that the oil being recommended was too thin. After a lot of correspondence with the Factory, I am now using a thicker oil, and the results are so much better. As far as I know there are only three people in the UK with Murci's that are using the same oil as me, which is really down to a bad communication of the problem, by Lambo dealers.

[RS4_Schumi]

How about 5W40 .... is 10W40 a bit thicker?

[roi354]

Quantum Synta Platinum is 5W40, has anyone who uses this had a cam wear issue or outright failure?

[Dippy]

xWy

x is the cold viscocity and y is the hot (operating temp) viscosity.

As I remember it, the differences between x=0, 5 and 10 only apply at very cold temperatures. Here the concern is start-up, and to ensure that there is sufficient lubrication particularly for the turbos (as you know, the turbos on the 2.7 biturbo engine have an oil bearing). Possibly using a 10W40 oil where temperatures can get really cold is a risk (if the oil is too viscous, it will not flow well through the oil lines). For me in the south of England I do not worry about it.

At operating temperature, 0W40, 5W40 and 10W40 have (or should have) identical viscosities. The issue here is if xW30 oil risks more cam wear than xW40 oil.

(N.B. I believe that xW50 oil should only be used for race conditions where you will get a consistently high operating temperature).

[Dippy]

By the way, I suspect that Audi's recommendation on oil was driven by the problems encountered by the American operation. As I noted, for the B5 S4 Audi only require a fully synthetic oil for variable servicing, and only for later cars fitted with the oil viscosity sensor. For timed interval servicing (which covers all early S4s) the handbook accepted the use of semi-synthetic oil.

This was then compounded by the market conditions in the US where oil services were sometimes free. I can't remember the exact details (which got from reading a lot of US forums years back), but I understand that it was common for S4s to be delivered with mineral oil for the run-in period, and then filled with semi-synthetic at a free oil service. As you'd expect, a lot of these cars were also chipped, so the stresses and temperatures were high for oils intended for more mundane cars. The obvious happened - there were a LOT of turbo failures and AoA had to replace a lot under warranty. This lead to the AoA technical bulletin which required techs to uprate the turbo oil lines for S4s which had turbos changed.

My guess (and it is only that), is that 0W30 is recommended to ensure that the turbos definitely get enough lubrication. The flip side may be that the while the turbos are more protected, the camshafts suffer instead.

Of course this all pales in comparison to the RS4 hard suspension/soft wheel issue!