Audi A4 cam wear

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Holy [censored]. Did that make any noise?

As far as replacing the cam yourself, read over the procedure a few times before making that decision. I replaced the cylinder head on a Jeep 4.0 without having done it before, and it went fine. The Jeep 4.0 is a big lawn mower engine in comparison to that Audi, but it is still just nuts and bolts.

Organize and label all nuts and bolts you remove from the engine, keep your work space as clean as possible, and take your time. Follow the book carefully and you should be fine. Take pics with a camera along the way to help you put it back together.
 
Originally Posted By: donnyj08
a lot of this issue was caused by quick lube bulk oil. the oil specs for these engines has to be met in order for them to live healthy long lives.


There is no way quick-lube bulk oil did that to that cam. Did you see it? At the most, quick lube bulk oil might create some more varnish and scuffing/weardown of those cams, which the hydraulic lifters would elegantly compensate for anyway, meaning the full valve lift might be down by a mere 3%, thats it.
 
That, unfortunately, is very typical of the exhaust cam on the passenger side of the 3.0. It is widely considered the worst engine Audi has made in the last 25 years. On any dedicated Audi board, the concensus for anyone asking about buying a 3.0 is to run in the other direction.

The replacement of the cams is not all that hard, you just need to peel back the layers until you get to the point of removing the timing belt and sprocket. There are special horseshoe shaped locking clamps to keep the engine in time while the belt is off, but they hold both cams still so one may have to be removed to pull the bad cam and replace it. If you decide to tackle this, order a good quality T30 3/8" drive bit. I've broken off too many of the parts store ones trying to break loose the cam cap bolts the first time. They're not torqued on tight, just locktited in there from the factory. You'll also need a new lifter bucket and a couple of oil change flushes for the metal shavings and chunks.

No amount of oil changes with unicorn tears would have stopped this from happening. Bad cams that weren't hardened properly coupled with being in close proximity to the exhaust manifold with little air flow to cool that side of the head doomed the cam. It's almost always on the middle cylinder (#2).

Quattro Pete - don't worry about your new 3.0t. They are polar opposites in engine design and should not have this problem.
 
That lobe looks like it's been running with very little or no oil.
The entire thing looks bad, not just the tip.
A blocked oil passage or poor design?
 
Here's a "better" pic. My phone has a heck of a time adjusting.

w2lsh4.jpg
 
Originally Posted By: CrawfishTails
Mice. I suspect mice. Find a nest in there? clue


How could this have possibly been mice?
 
Originally Posted By: dlundblad
Originally Posted By: CrawfishTails
Mice. I suspect mice. Find a nest in there? clue


How could this have possibly been mice?

How could you possibly think he was being serious?
smile.gif
 
Originally Posted By: Quattro Pete
Originally Posted By: dlundblad
Originally Posted By: CrawfishTails
Mice. I suspect mice. Find a nest in there? clue


How could this have possibly been mice?

How could you possibly think he was being serious?
smile.gif




Of course he wasn't serious. He clearly meant rats...
 
Thing that puzzles me is that threeputtpar's explanation above didn't mention anything about lack of enough oil flow. He said temperature and hardening was to blame. I can see the hardening problem might have done it, but I'd suspect oil flow.
 
If it was poor oil flow, wouldn't the more of the shaft have been affected? I would suspect it would at least been "blued" from the excessive heat? Perhaps some sludge/ crud build up?
 
Last edited:
Looks like a bad casting. Problems like this can be caused from incomplete

melting of steel during casting. (The cake was not baked long enough.)
 
Originally Posted By: DoubleWasp
What specifically is required of the oil to keep a cam from eating itself? Most modern engines seem to do fine on their own.

VW did invent 505.01 oil because they were having problems with the PD diesel engine. It didn't work all the time. Sometimes I wonder if it would benefit other VW engines that used 502 and 505 oils.

One thing really scares me about this repair job. I really fear what chunks of the old cam have done to other parts of the engine.

Another post mentioned getting a cam from someone other than VW. I don't know if that is possible or not, some companies make PD diesel cams, due to the number of failures. In addition, some companies make cam buckets that are redesigned so they are more durable.
 
This actually happens on the 2.7t exhaust cams on the passenger side, too. Most of those cases are in the B5 S4 versus the C5 A6 and allroad, because of the smaller engine bay not dissipating the heat. But the number of instances on the 2.7t is much smaller than on the 3.0.

The root cause is insufficient hardening of the cam, and the secondary cause is poor oil flow in that area. I'm sorry that I missed the oil flow in my previous post. The high under hood heat certainly exacerbates the problems.
 
Originally Posted By: DoubleWasp
What specifically is required of the oil to keep a cam from eating itself? Most modern engines seem to do fine on their own.


In general, an oil has to have anti-wear additives that work at a good temperature spread, cold through hot. Boundary Lubrication, metal-to-metal, occurs at the cam lobes. ZDDP of course is the old and current choice, but it does its work warm mostly. Moly or esters work at lower temperatures from the tech papers I've read on this matter. Boron and Titanium AW additives I'm not sure about. All work to reduce wear on cams.

Of course, this case in this thread is mostly about metallurgy, heat, and/or oil flow.
 
Dlundblad, I know it's only been a couple of days since your first post. What's the status? Are you going to replace that cam?

I'm new to VW/Audi ownership. We tend to keep cars a long time, but over the years I've owned Hondas more than anything else. We had a Grand Cherokee and a Grand Caravan sprinkled in there as well.

Before I tackled the timing belt on my A4 (2005 - B6 platform) I purchased a Bentley service manual on Amazon. I opted for the hardcover - I didn't want to rely on a laptop in the garage. I highly recommend that book. It's pricey (over $100), but I rationalized it thusly: Dealer quote was over $2500 for the job (parts plus 8 hours labor). I was able to purchase a very complete parts kit, plus rent the specialized VW/Audi tools, plus purchase the Bentley manual, plus purchase the $350 VCDS (VAG-COM) interface for around $1000. So even with the very expensive service resources (VCDS and the Bentley manual), I figure I'm still ahead by a good $1500.

It was a big job, but doable. My case was complicated when two of three screws broke while removing the idler pulley bracket, and when the head of a bolt securing the PS pump stripped clean. Dealing with those three fasteners cost me about 1.5 days. They surely would have broken for a wrench at the dealership too - though they probably would have been better positioned to deal with the challenges than I was. But I figure it still would have added a few hundred bucks' worth of labor time to the job.

I guess all that is the long way around saying that you could combine the cam replacement with a TB service. I don't think the Bentley manual goes into a huge amount of detail on pulling/replacing a camshaft, but that should be pretty straightforward once you deal with all the timing components -- which the manual does an excellent job of laying out. It also explains how to put the front end of the car into "service position". That whole front carriage (radiator, headlights, etc) pulls forward about 3" - 4" to provide room to service the front of the engine. It doesn't sound like much extra room, but it really is plenty of space for the TB job. It's what I had to work within to drill out two broken bolts and install helicoils, even...

Good luck.
 
I have never seen a cam look like that before.
And how was there no shrapnel in there from the lobe chewing away.
The cams may be garbage however I'm impressed that the engine isn't cooked.
 
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