Procedure for the two easy chain tensioners

[jchapura]

I've got the three chain tensioners sitting on the shelf waiting to change with the oil in few weeks.

From the bottom, the IMS (I think) tensioner is the easiest one - totally exposed for a socket. The other one accessible from the bottom is "fenced" by a couple of metal coolant tubes. Can the coolant tubes be temporarily moved out of the way by undoing their straps to gain sufficient access to the tensioner? Or, do the tubes have to come out by decoupling them from their in and out rubber hoses? (I'm trying to avoid cracking open the coolant system...)

 

Does the cam have to be locked in TDC with a pin through the pulley hole? Is there still a chance that any of the three chains could jump a tooth while removing the existing tensioner or putting in the new one? I plan to complete each tensioner completely before moving to the next one (two tensioners will never be out at the same time).

 

Any other tips or tricks?

Thanks for any advice.

[JFP in PA]

Anytime you remove the hydraulic chain tensioners in one of these engines, the engine needs to be locked at TDC with a pin through the lower pulley, and the cams locked at the cylinder heads with the correct cam locking plates for the style engine you are working on (three chain or five chain).  To do otherwise is to risk having the cams move due to spring tension and cause the now slack chain(s) to jump time, which will then require an enormous amount of work to correct.  The cam locking plates are cheap insurance against that happening,

[fastsvo]

At what mileage is it recommended to replace the chain tensioner on a 997?

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[JFP in PA]

There isn't any mileage per se, you change them when needed.

[jchapura]

I too haven't read that there's specific mileage threshold (although I've read that they do "age" - read - leak down and/or lose tension). I did read from Raby that there should be no noise from the chains, for example, upon cold start (even transient). I'm hearing a 1-2 second period of chain rattle at cold start so I'm going to preemptively change the two easy ones first and see what rattling is left over. I've read it's usually the IMS chain tensioner which is one of the easy ones. I'll do it at my next oil change even though not a lot of oil leaves the case. You do have to have one special tool (actually two of the same) - to lock the camshafts in position when you're locked at TDC with a 5/16 inch drill bit. I plan on making (the lock tool is rather simple) them from some aluminum flat bar since the cheapest I could find for one (as part of a kit) was $60.

 

[jchapura]

So, I got up under car to start taking measurements for the camshaft lock (similar to 9686) and noticed how little room there was at the front and rear of the engine to place the tool. In the rear (drivers side), the underside of the engine mount area seems to be in conflict. In the front of the engine, part of the frame crosses through the work area.

 

Can the standard lock tool be put into place (front and rear) while the engine is in the car?

 

[JFP in PA]

1 hour ago, jchapura said:

So, I got up under car to start taking measurements for the camshaft lock (similar to 9686) and noticed how little room there was at the front and rear of the engine to place the tool. In the rear (drivers side), the underside of the engine mount area seems to be in conflict. In the front of the engine, part of the frame crosses through the work area.

 

Can the standard lock tool be put into place (front and rear) while the engine is in the car?

 

 

Depending upon how the vehicle is equipped, you will probably need to lower the engine slightly.

[Mark Duenas]

  Depending upon how the vehicle is equipped, you will probably need to lower the engine slightly.

 

Does one need to own two cam locks to do the procedure or can each side be done in sequence by leaving the drive shaft at tdc then locking the drivers side...Replacing both the ims tensioner and the drivers side first... Then after that one is done, with the drive shaft still locked at tdc, locking the passenger side cam shaft and replacing the remaining tensioner? Thanks for your help!

 

 

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[JFP in PA]

Welcome to RennTech 

 

What is the year and model of the car?

[Mark Duenas]

Welcome to RennTech 
 
What is the year and model of the car?

1999 Porsche Carrera, 3.4l


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[JFP in PA]

12 hours ago, Mark Duenas said:

1999 Porsche Carrera, 3.4l


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OK, you have a five chain engine, which by design is less prone to jumping time during service.  You will need to pin the crank pulley at TDC, then pull the cam plug on the driver’s side rear cylinder head and install the shorter of the two cam locks.  Once that is done, you can remove and replace the hydraulic tensioners one at a time.

[Mark Duenas]

Thanks for your help!


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[jchapura]

With regard to my 2005 C2S (three chain, right?), can I lock the pulley at TDC, and then use a single 9686 tool to lock the camshafts on one side but swap-out all three tensioners, one-by-one (without moving the 9686 tool)? If a single 9686 tool position can work for all three tensioners, which side should it be placed on - drivers or passengers?

[Ahsai]

The cam lock tool should be placed on bank 1 when replacing the IMS tensioner and bank 1 tensioner (same as IMSB r&r procedure).

 

The tool should be placed on bank 2 when replacing the bank 2 tensioner.

 

Note the above cannot happen at the same TDC. You need to rotate the crank 360 between the above two.

Edited October 4, 2017 by Ahsai

[jchapura]

Do these seem like reasonable steps to change-out the tensioners? All comments welcome.

 

Tools:
-Tensioner torque 59 ft-lb
-32 mm socket
-fairly large 6 mm(?) hex key (for bank 2)

 

Reference info:
-while facing the rear of the car; looking towards the front
-cylinders 1,2,3 - drivers side, left side; this is bank 1
-cylinders 4,5,6 - passengers side, right side; this is bank 2

 

Parts:
-primary/ims chain tensioner - one ring marking; 996-105-180-58-M100; installs on crankcase near oil filter area; rear of engine
-cylinder bank 1-3 - two rings marking; 996-105-186-02-M100; left lower area on cylinder head; points straight down
-cylinder bank 4-6 - no marking; 996-105-188-02-M100; right upper area on cylinder head
-crush washers usually come with the tensioners
-camshaft plugs - 4x - 996-104-215-54

 

Steps:
-index the engine to TDC
-remove the bank 1 camshaft plugs (looking into engine bay; to the left and look down)
-inspect the camshaft slots to ensure they are straight up and down, if not rotate the engine 360 deg; inspect the camshaft slots to ensure they are straight up and down
-lock the crank/pulley with a 5/16 inch or 8 mm pin
-lock the camshaft for bank 1, rear of engine, left side
-pump up the primary/ims and bank 1 tensioners in oil prior to insertion
-replace the IMS tensioner (has one ring) (flywheel end of engine; right side of engine; a few inches up from bottom of engine)
-replace the bank 1 tensioner (two marking rings) (left side/bottom of engine)
-remove the camshaft lock
-install the new camshaft plugs

 

-remove the TDC pin
-rotate the engine 360 deg
-lock it with a 5/16 inch or 8 mm pin
-lock the camshaft for bank 2, front of engine, right side
-move the AC compressor out of the way
-pump up the bank 2 tensioner in oil prior to insertion
-replace the bank 2 tensioner
-install the AC compressor
-remove the camshaft lock
-install the new camshaft plugs
-remove the TDC pin
 

[Tarek]

I know it's an old thread - and older topic - but it remains highly controversial and confusing.

 

All updated IMS bearing replacement procedures call for removing all 3 tensioners while the camshafts are locked.  Replace O-rings and reinstall upon completing the IMS bearing replacement.

 

Meanwhile, when replacing the tensioners themselves, all procedures point to the importance of doing one tensioner at a time, rotating the engine, etc.  This in itself is one of the steps in the procedure above.  How can it be possible to do one at a time, when doing so is a violation of the procedure above (all 3 tensioners must be removed while performing the IMS bearing replacement)

 

  Am I the only noticing the two are in conflict?

[JFP in PA]

3 hours ago, Tarek said:

I know it's an old thread - and older topic - but it remains highly controversial and confusing.

 

All updated IMS bearing replacement procedures call for removing all 3 tensioners while the camshafts are locked.  Replace O-rings and reinstall upon completing the IMS bearing replacement.

 

Meanwhile, when replacing the tensioners themselves, all procedures point to the importance of doing one tensioner at a time, rotating the engine, etc.  This in itself is one of the steps in the procedure above.  How can it be possible to do one at a time, when doing so is a violation of the procedure above (all 3 tensioners must be removed while performing the IMS bearing replacement)

 

  Am I the only noticing the two are in conflict?

We do this for a living, and have never seen legitimate IMS retrofit instructions that says to rotate the engine in between the installation of the hydraulic tensioners. It is unnecessary,and extremely risky as the cams could jump time when rotating the crank with any of them out.