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Old 02-04-2013, 09:09 AM   #1
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Confused - chain pad question

The chain tensioner / pad question confuses me greatly. I hope someone can clarify.

I have an 01S. It has variocams. This leads me to ask the following questions:
  1. Are the variocam pads that ones that wear out as the miles pile up?
  2. If so, am I right that one must remove the engine from the car and split the case to replace them?
  3. Are there are other pads that the chains run on?
  4. Are these the ones that wear out and lead to the chain jumping timing?
  5. Does one need to pull the engine and split the case to replace these other pads?

Separate from the pad question, my search of the bulletin boards suggests there are three chain tensioners in the M96 engines.
  1. Am I right about there being three?
  2. Are these a potential failure point that allows the chain to jump timing?
  3. Does one need to pull the engine to replace the tensioners?
I'd greatly appreciate any insights you can provide. Thanks

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Old 02-04-2013, 09:37 AM   #2
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Answering the latter of your questions, there are indeed three chain tensioners and they can be accessed without pulling the engine. Two from the bottom of the engine and one from behind the drivers seat access panel. To change these out it would be advisable to lock the motor in TDC position before removing and replacing. To do the one behind the drivers seat, I found that a set of spanner wrenches saved me from having to remove the power steering pump. Without them, you will have to pull the pump out as well.
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Old 02-04-2013, 09:43 AM   #3
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Hello Thom.
Since this subject is very interesting for me as well, I have done some research on it.
(although I don’t have rattle, my cam deviation is -5,-6)
I will try to answer some of your questions, and hope some others will chime in, to correct me, or add more info.

1. Are the variocam pads that ones that wear out as the miles pile up?
- Yes. The variocam pads are responsible for cam deviation.

2. If so, am I right that one must remove the engine from the car and split the case to replace them?
- No. in order to remove the cam pads, you will need to remove the camshafts.
To do that you will need to lock them both (using a special tool) and remove the cam covers. It can be done when the engine is still in the car.
(process is well documented in the 101 book)

3. Are there are other pads that the chains run on?
Yes. Look at this diagram.
Porsche Boxster Camshaft Parts
parts 33,30,19,22 (and the cam tentioner pads 9)

4. Are these the ones that wear out and lead to the chain jumping timing?
I think all worn pads can lead to jumping timing. However, most likely is the pads for the IMS to cam chain (30,33) and the IMS tentioner pad (19)
5. Does one need to pull the engine and split the case to replace these other pads?
Still looking for an answer on that. There is no need to split the case for sure, but Wayne (from pelican) wasn’t able to tell me (in another tread about this subject) if it can be done with the engine in the car.

Separate from the pad question, my search of the bulletin boards suggests there are three chain tensioners in the M96 engines.

1. Am I right about there being three?
Correct. 1 tentioner is for crank to IMS chain (part 35), and two tensioners for IMS to cam chains (24&34).
When doing IMSB retrofit you need to remove 35&24. They are located at the bottom of each bank, on the transmission side.
The third tenssioner is located at the top of bank 2, right under the AC compressor.

2. Are these a potential failure point that allows the chain to jump timing?
I believe in extreme cases when the pads are completely worn out, then yes.
I read on the forum some posts about brown plastic particles in the oil. I guess it’s one of the symptoms.

3. Does one need to pull the engine to replace the tensioners?
No. see answer to question 1.
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Old 02-04-2013, 12:10 PM   #4
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I too have a 01 S (62K miles) and my cam deviation is also -5 -6 and thinking that the tensioner cams need replacing.

Very interested to see whether its just part 9 that needs replacing or some of the others as well.

I guess replacing the easy ones first and re-measuring the cam deviation is a good approach.

I don't notice any chain rattle yet on startup. I'll check my oil filter for particles as well in the next couple months at the oil change.
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Old 02-04-2013, 01:14 PM   #5
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there is also an excellent rebuild video on YouTube for an 01S:
Porsche Boxster S engine rebuild 12 - YouTube

check out chapter 8:

Porsche Boxster S engine rebuild 08 - YouTube
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Old 02-04-2013, 01:44 PM   #6
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here's the most helpful pic i've found ...

http://www.pelicanparts.com/techarticles/Boxster_Tech/16-ENGINE-Camshaft_Swap_and_Chain_Tensioner/Gp1800.pdf

it shows the various pads and tensioners.
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Old 02-04-2013, 05:45 PM   #7
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Wow, your comments really helped. The links were a really insightful too. Thanks so much.
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Old 02-04-2013, 07:31 PM   #8
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Quote:
Originally Posted by jb92563 View Post
I too have a 01 S (62K miles) and my cam deviation is also -5 -6 and thinking that the tensioner cams need replacing.

Very interested to see whether its just part 9 that needs replacing or some of the others as well.

I guess replacing the easy ones first and re-measuring the cam deviation is a good approach.

I don't notice any chain rattle yet on startup. I'll check my oil filter for particles as well in the next couple months at the oil change.
Ray, your car is still within factory specs. Change your oil often and pay attention to the bits in the filter. Your car may go another 30K miles without issue.

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