A sad day for my bank account...
 

Just heard back from my indy regarding my annual check and service: camshaft deviation angles are now very close to 6 degrees on both banks.

ugh.

Around $2k to replace both camshaft wear pads.

2000 2.7L base with 69,000 miles -- probably to be expected. Looks like I'll have to give up the champagne and caviar for awhile...

That's a bummer.

Having done this job myself recently, I think if I had to do it again I might pay $2k.

I'm curious, what made you check your camshaft deviation in the first place? Is this really performed during annual check and service??? I never really heard of such a thing.

Takes a few seconds extra with PIWIS/Durametric if it is already hooked up. Good PM check.
Next step is a "while you are in there" list to minimize future bank balance damage?

Not trying to hijack the thread, but would would be considered good and bad cam deviations. I would like to check mine next time I hook up the Durametric.

Under 6 is çonsidered within spec.

I asked my indie to check the values, knowing that I was probably pretty close. This is a wear item on these cars, and after around 60-65k miles, these pads just wear out. If you don't replace them, they'll eventually cause really big problems that are even more expensive to fix.

I am curious to know if replacing these pads was a part of the standard maintenance schedule. My guess is a lot of owners decided to trade the car in rather than do the job, passing the problem down to a second owner who either didn't know the problem existed, or was unwilling to spend the money, thus perpetuating the issue.

Oh well, this is a wonderful little sports car. I will never, ever get my money back out of it, unless you consider the miles of smiles when I drive it.

Sorry to hear at only 69k miles? So, just out of curiosity and for future reference does anyone know if this can be done without pulling engine? Is this a job where you have to pull both bank cam covers? Will covers come off within car?

Are you sure this is a common wear item? MarcW on Pedrosboard has over 300k miles on his 02 2.7L that he bought new, and I've never heard of him replacing the camshaft wear pads.

EDIT: Confirmed with MarcW that he has not had to replace his Camshaft wear pads. He's got over 310K miles on his 02 Box.

Yes you can remove the cam covers with the engine in the car but it is a horrid job and you need cam holding tools and a tool for compressing the Actuator.
Unless you are very well equipped for this and have lots of time,patience ,and very skinny hands and research .I would not recommend it. Yes I have recently done it but as JFP astutely hinted when I started the job- it is like building a ship in a bottle. And you need 2 !

Was there a thread on this??

Pelican cover it but with engine out.

Make sure the engine has been for a really good run before checking the angles

What else needs to be done while ur in there? I was going to replace the chains

Mine are around -6 (2000 Boxster S, 130K miles), I talked to some folks about getting it done, and one of them said to come see him when the CEL comes on, which I think (I may be recalling incorrectly) he said was at +-9. I check it from time to time and it has been holding steady over the 30K miles I have owned the car.

Chains - that is an engine out job unless you want to try split links?

the short chains come out with the actuator

Of course they do. You have no choice with the cam-to-cam chain. The issue would be the IMS to cam chain.The clue is the phrase "split link"- only applies to the longer IMS to Cam chain.Just rebuilt all this stuff.

I have had 3 M96 cars and never had an issue. All told close to 300k miles over all three. I had one engine rebuilt but that was for performance, as it had no issues at the time. It may be a wear item, not saying it isn't, but not sure why I haven't had the problem. I've had most of the known maintenance problems. No engine failures but I got IMS taken care of as soon as there was a fix


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Wish I had your luck! Not sure why you haven't experienced any issues with these as well. There's actually been quite a bit posted on this forum and others about these wear pads, and not taking care of the issue gradually leads to a worsening list of problems. At some point, the cam deviations will lead to a CEL. If you continue to ignore the issue, the pads will wear completely through, and the chain starts to run directly on the timing chain tensioner ($1k each). At some point, maybe as your punching it down an on-ramp, or on the front straight on a DE day, the chain tensioner will not be able to keep up and the motor will slip timing.

My indie is a certified LN IMS installer, and he won't touch the car with a replacement IMS unless cam deviations have been corrected.

I will check it with durametric for sure
My indie has never mentioned it. Lord
Knows I have done
Everything else


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Deviation - we usually assume it is worn chain pads on Variocam Actuator - the cam-to-cam chain. Debris in the pan would confirm that. But sometimes Deviation can be caused by other factors that are seldom mentioned.
It would be helpful to read an expert definition and explanation of Deviation as read by Durametric.

It's pretty simple actually; if the cam deviations are steady and outside +/- 6 degrees, you need chain wear pads. If the numbers are outside spec, but bouncing around all over the place, something is moving in the cam drive, usually the IMS shaft.

I was thinking of the more obscure causes like a bent reluctor . worn chin links,weak chain Tensioner(on the IMS to cam chain) , leaking oil past a worn piston/Actuator. I have no idea if any of these are significant ,nor if there are others.
There are some excellent Threads on Rennlist that stress simple things like making sure the engine is thoroughly warmed up before accepting a Deviation reading.
https://www.renntech.org/forums/topic/46101-camshaft-position-1-deviation-of-897/?_fromLogin=1

Damaged component's tend to push the deviation values one way or the other; the actuators tend to either show no response, or literally go to ridiculous numbers. Sensor failures tend to not give you any values.

Measuring cam deviations has always required a fully warmed up engine, preferably one that has been driven some distance, because the system is oil operated, the flow characteristic's of the oil can alter the data. You need steady state oil to get steady state deviation values.

Update: cam covers are off and my indie confirms that wear pads were very badly worn. He texted me pictures and...he's not kidding. Very deep grooves on all of them, and the little oil tubes on top were completely blocked with plastic shavings.
Money. Well. Spent.

Things I've learned from my PCA tech guy in the meantime:
- Most of the wear on these pads occurs during the first few seconds of engine startup. They are oiled pads, but they're one of the last components to receive oiling after engine startup because of the distance from the oil pan.
- Frequent oil changes (as if you needed another reason) help flush the plastic bits and prevent the oil feed tubes on the pads from clogging and accelerating wear.
- The wear pads are plastic to reduce chain wear.
- Catastrophic engine failure can occur from chain pad wear, but not from slipped timing (the 5 chain engines tend not to slip timing). The plastic bits from the pads can clog oil passageways as well as the oil pickup tube and cause oil starvation. Unfortunately, you may not realize it was actually chain pad wear that caused the starvation issue.
- There is some evidence that, outside of engine startup, pad wear is greatest at 2200-2500 rpm. So, keep the revs up, I guess.

I should be picking her up on Friday. I'll keep you posted.

Update
 

Here are my worn cam chain wear pads. Replaced at 69k miles. The surface on one of them is paper thin. :eek:

http://986forum.com/forums/uploads02...1495203589.jpg
http://986forum.com/forums/uploads02...1495203599.jpg

Thanks for posting this update.

What did your Indy charge to get this work done?

It's a little hard to break out the labor as I also did the front motor mount (totally shot) and an oil change. The total for everything was $2800. For the wear pads alone, I would guess around $2100. Quite a lot of labor involved for this job -- skilled labor. Not an easy job.

This is how my pads looked at 129k miles (when my engine gave up the ghost)

http://i1314.photobucket.com/albums/...pstbzmvzk9.jpg