996Driver4528

My car is a 2000 996 6-speed coupe with approx. 140,000 miles. Since the cam deviation angle on Bank 1 was 7.6 degree (more than the 6 degree limit), I had the pads on the variocam chain tensioner replaced by a Porsche independent mechanic. After the replacement, however, the chain deviation angle went down only a little bit to 6.75 degrees.

What could be the reason for that? Are the camshaft deviation angle sensors identical on both banks? I was thinking of swapping the sensors to verify that the issue is not due to a bad sensor.

Thanks

P9C

Perhaps the chain is stretched? Or the chain guides and/or tensioner are worn?

Dharn55

Were the cam settings re set after the pads were replaced?

De Jeeper

Maybe this was done but pull the battery cables and check again. Its been my experience that u should get a 2.5-3.5* change from pads.

Also can u see the "actual values" change about the same amount when u rev the car past the vario engaugment rpm? (I think over 3500)

DSC800

I don't think I've seen anyone report more than a ~2* improvement. The pads would need to be pretty much gone to show much more. Chain, sproket, tensioner and guide wear probably account for the other 3+ degrees, this along with not being able to set it back to factory without the fixed tensioner tool (Porsche tool 9599). All this aside I still haven't heard a good explaination as to why it is always bank 1 that is the problem and bank 2 stays well within spec.
I checked my reading a couple weeks ago and they are 1.6 / .95 which is solid from when I did the job last year. I'd ask your Indy what he thinks about adjusting the cam sproket to bring it to spec (not too hard, drop the engine a little and remove scavenge pump to access).

996Driver4528

When my Indy replaced the 'Vario' pads, he also removed and inspected the bank 1 tensioner (for the long bank 1 chain). He said that it was leaking and needed to be replaced. We did not have a replacement tensioner available, so we left this for another time. Based on your message perhaps this is the cause of much of the deviation angle.
Also, could you please clarify the following:

• What is the exact purpose of Porsche tool 9599 for my issue? I thought that it is used for removal and installation of the IMS.
• What do you mean by 'adjusting the cam sproket to bring it to spec'? I thought that my Indy already did this when he installed the new pads and the new 'short' chain on the 'Vario'. Do you mean that he should re-check the work done to confirm that everything was done to spec.? Or you talking about a separate operation?

Thanks

pdxmotorhead

I don't understand how a Porsche mechanic would give the car back out of spec. It's < 5 minutes to check deviation after his work.
I'd take the car back and ask WTH..

996Driver4528

The deviation was measured with the Porsche scanner after the repair and found out of specs. We are all trying to figure out what is going on.

168Sierra

First thing I would do is get a new tensioner, pump it up with oil prior to installation then install it. A weak tensioner will allow more cam shaft deviation. IF it has the original tensioners, I would replace all three. I have replace them all on all my cars.

DSC800

,
No doubt, a leaking tensioner will cause slack and contribute to greater deviation, so yes, it needs to be replaced. That's easy, do it and let us know, fingers crossed.

• The 9599 tool is the "fixed tensioner" that Porsche used when they built the engine. It should be used when re-timing the engine but it's not made anymore so everyone just uses their oil filed tensioner.
• After you run the engine and check the deviation you can remove the scavenge pump and loosen the four sprocket bolts to advance/retard as necessary. For me this was a separate operation since I would adjust slightly then replace just the scavenge cover (not the whole pump) to run the engine again to re-check the deviation. Repeated this 3 times to achieve <2 degrees. It took a couple hours.

Porsche static timed the engine to 0 degrees during assembly. Running the new engine took up all the slack, including the tensioners under load, giving a 1 or 2* dynamic reading. Over time and wear the deviation increases. Read my thread from when I did this last year and take a look at this old link below from someone who made their own "fixed tensioners". It's my opinion that when you "pump up" the tensioners with oil they loose this pressure quickly, well before you can get to locking down the cam sprocket. To compensate I ran the engine and adjusted three times to dial it in. Advancing the sprocket just 1mm would result in a 2 or 3* change. Good luck and I hope this helps a little.

http://986forum.com/forums/performan...rs-timing.html

996Driver4528

Many thanks for your explanations. Armed with the information provided by you and the other members that replied to my post, it should be possible to bring my valvetrain back to specs!

pdxmotorhead

Ah,, I missed something in there somewhere.. That makes more sense.