Tensioners

[drewbz818]

Does motor need to be removed to replace them? And when should they be replaced?

[JFP in PA]

Can be done with the engine in the car, this covers the procedure fairly well:Pelican Technical Article: Boxster Camshaft Upgrade / Chain Tensioner Replacement - 986 / 987

[drewbz818]

Thanks for info, if I may ask is it a hard task or pretty straight forward?

[JFP in PA]

Complicated, but not difficult. It does require some specialized tools…..

[Wayne 962]

What is your thinking behind replacing them? How are you figuring that they are bad? Any specific symptoms?

-Wayne

[drewbz818]

Well Wayne, the rattle at,start up, and I read they should be changed at 80k, not sure if any warrant a change. Any advice is always apprieciated.

[Wayne 962]

I'm not sure - I haven't formed an opinion on "tensioner life" just yet. There have been reports of some failures, but not nearly as many as intermediate shaft bearings (IMS). Changing them is not an easy job at all. You need to lock the camshafts, and then replace them from within the engine bay. The ones you can remove from the bottom of the engine are easy - the one under the A/C lines on the top is a bear to get to.

-Wayne

[JFP in PA]

Wayne, I was of the impression from what I have read that Porsche released an "updated" tensioner design, but off hand I have no idea what years or models it covers................

[Wayne 962]

Originally Posted by JFP in PA

Wayne, I was of the impression from what I have read that Porsche released an "updated" tensioner design, but off hand I have no idea what years or models it covers................

I did some research on that for the book, and yes, they did update the tensioners, but they are not backwards compatible, if I recall correctly, because the ramp inside the engine also changed to mate with the tensioner. I'm pretty sure this is the case, although my memory is slightly fuzzy on this. So, if you're rebuilding, you can update the tensioners, but if you want to install the newer style without opening the engine, you can't.

I'll have to dig through my notes a bit more on this...

-Wayne

[BYprodriver]

The IMS to crank chain tensioner was updated with a preload spring to prevent the chain "flapping" if the tensioner oil leaks down, it is retrofitable with no other mods & I highly recommend this. The 2 cam chain tensioners have been updated but I didn't see any external changes other than 1 (4-6 bank I think) has gone to a 11mm allen from 32mm hex head for a lower profile. I am waiting for a good Webcertificate to order these for the engine I am building.

[Wayne 962]

I checked my files. There is a Porsche Technical Bulletin on this, I uploaded it here: http://www.pelicanparts.com/techarticles/Boxster_Tech\16-ENGINE-Camshaft_Swap_and_Chain_Tensioner/Gp1800.pdf

The tech bulletin says:

To reduce engine noise, the drive chain for the intermediate shaft (primary drive) has been changed
from a roller-type chain to a tooth-type chain (figure 1). The changes were introduced into production
on August 15th, 2000, as of engine numbers:
M96.22 65 1 00501 2.7 liter
M96.21 67 1 00501 3.2 liter
The sealing ring on the bearing flange for the intermediate shaft has been changed from an O-ring (figure
8) to a 4 mm wide sealing ring with three sealing lips (figure 9). The changes were introduced into
production on September 12th, 2000, as of engine numbers:
M96.22 65 1 02353 2.7 liter
M96.21 67 1 02086 3.2 liter
Note: The new style seal, which includes a modified bearing flange, is to be used for repairs on earlier
engines. The old style seal is no longer available.

The following parts have been changed because of the conversion to the tooth-type chain for intermediate
shaft drive:
1 - Drive chain for intermediate shaft
2 - Crankshaft
3 - Intermediate shaft
4 - Chain tensioner
Note: Roller-type chains remain in use for driving the camshafts.

But, most importantly, it says:

After existing supplies of the previous parts have been used up, the new parts can be used as
replacements for all Boxster engine types M96.20, M 96.22, and M96.21.
A mixed configuration is not permissible, as the parts are matched with each other. The previous
chain tensioner, part No. 996 105 180 54, is still available and may continue to be used on engines
that have the previous style drive chain installed.

Which leads me to believe that you shouldn't install the new tensioner with the old style chains. I remember now, when putting the book together, there was too much confusion to make a recommendation that might have ended up being incorrect in the long run.

Anyone have any more experience with this?

-Wayne

[Wayne 962]

Originally Posted by BYprodriver

The IMS to crank chain tensioner was updated with a preload spring to prevent the chain "flapping" if the tensioner oil leaks down, it is retrofitable with no other mods & I highly recommend this.

According to PET, the current PN for this is 996-105-176-51. However, when you punch it into the Porsche price database system, it comes up as superseded to 996-105-188-01, which is the 987, Cayman, and 997 part number. So, it would appear that the newer 987 part number is indeed compatible with the older cars, and is indeed probably an upgrade (although I can't find any tech bulletin that states that specifically).

-Wayne