Pulling VarioCam actuators

[Gary_d]

I'm getting ready to pull the VarioCam actuators on my 1997 5 chain engine due to out of spec cam variance on bank 1. Hoping it turns out to be the wear pads. I have no idea what the variance is, but with a solid CEL it must be more than it should be.
Question is, is it possible/feasible to do it with the engine in the car, or is that asking for trouble?
I have no problem pulling the drivetrain if I have to, but if it can be done in place it might save some effort. Looks like it could be a royal pain though.

[JFP in PA]

Before you take anything apart, get the car scanned to find out exactly what the cam deviations are (Durametric, PST II, PIWIS); otherwise you may end up replacing some very expensive bits for no apparent reason.

[Gary_d]

Just went and pulled the plug and ordered the Durametric from Pelican. I'll post the variance results here when I get the tool.

[Gary_d]

More confusing now with the Durametric outputs.
The faults that showed were:
P1531 Cam adjust bank 1 (what I was diagnosing in the first place)
P1121 Heating power O2S behind CAT bank 2
P0160 O2 sensor behind CAT - cylinder (4-6)

When I ran the actual values for cam variance, both banks came out with a -6.0 across the rev range. Both sides gave the flatline -6.0, but bank 1 showed red and bank 2 was blue.

I used Durametrics versions 5 and 6, both gave the same results. I tried both in case I received a gen1 cable instead of gen2.

[Gary_d]

OK, so after my 'duh' moment with the color of the graphs...! (I was a systems analyst for 21 years, think I should recognize graph indicators)
Both cams show a variance of -6.0 across the board, straight line through the rev range.
When I use the Durametric to shut off the VarioCam on bank2, there is an appreciable change and the variance drops to 5.0. Trying it on bank1 makes no difference in engine or variance.
I'm going in now to check the solenoid on bank1, any recommendations on testing the solenoid?

[san rensho]

I would first clear the codes and see what comes back. I had a stored (no CEL) 1531 code that never came back after being cleared. Then, I would work on the O2 sensor error codes and see if you can resolve them.

The last thing i would do is dig into the cam actuators. +-6 is the limit on cam deviation, but if you are not having any performance problems, why do anything.

[Gary_d]

That's kind of where I'm leaning at this point. I cleared the codes several times, it comes back right away.
I guess my concern is, why are they both at -6 but only bank1 throws the code?
When I shut down that side with the Durametric, it didn't seem to make a difference. I'm wondering if the solenoid is not working. Since it's an easy access, I may just pull it to test it out.

[Gary_d]

Bump

Got it sorted out! Before digging deeper, I decided to try some simpler things first.
Apparently, the right solenoid wasn't getting power. I pulled, cleaned and replaced all the wire connections to that side and.. it works! Durametric now gives a definite response on both sides.
The O2 sensor on the left bank was even easier. The PO must have used one of the aftermarket replacements where you plug the terminals into the original connector. All 4 wires were simply laying up in the heat shield not attached. Must not have been installed tight enough. I may have accidently knocked them out during the IMS replacement too. Reinstalled them (making sure they were tight).
Cleared of the codes and drove it for all of my errands yesterday, no repeat of the CEL.
Durametric says everything is kosher today.
I'm still running a solid -6.0 on both sides, but that's in spec.
I guess at this point I'll finish out the summer with it, and probably make it a winter project to redo all of the timing chain bits and pieces.

Consensus? Sound reasonable?

[BYprodriver]

Great work! You didn't post your cars mileage but unless it's under 50K the cam chain wear pads probably need to be replaced with the longer wearing wear pads. this will make the engine run much smoother especially at high rpms.

[Gary_d]

Thanks BY.
It's at 120k, and I bought it at 101k with no documentation (Porsche dealer trade in), no way to know what was done or not. That's one of the reasons I did the IMS bearing, just felt better knowing it was taken care of.
That's why I figure it'll be a winter project to redo the timing chain end of it. I'll feel better knowing it's right.
I've always specialized mostly in British cars and motorcycles (and Volkswagens) this car has opened a whole new world of complications! Rule of thumb for the British is to send a crack team of engineers around the world to discover an oil leak and design a vehicle around it.
My 911 has never been a problem over 15 years, everything is fairly simple (tongue firmly implanted in cheek)!
Good thing I like a challenge!

[Meir]

Hi Gary.
It will be great if you will document the process and post it here.

[Gilles]

Originally Posted by BYprodriver

Great work! You didn't post your cars mileage but unless it's under 50K the cam chain wear pads probably need to be replaced with the longer wearing wear pads. this will make the engine run much smoother especially at high rpms.

BYprodriver:

My 07 CS is getting closer to the 60k mark and it's running great, but I was not aware the the cam chain wear pads should be replace around the 50k mark.

It seems that the procedure to replace the cam chain wear pads are the same steps that are used to replaced the IMS: mentioned here numerous times "lock the crank at TDC, lock the cams (with the special tool), then remove the variocam actuators and replace the wear pads" perhaps with the upgraded LN billet machined ones.

Question: Is the tool to lock the cams the only special tool required? Is this a straight forward job that can be accomplished by a DIY with standard tools?

.

[BYprodriver]

Originally Posted by Gilles

BYprodriver:

My 07 CS is getting closer to the 60k mark and it's running great, but I was not aware the the cam chain wear pads should be replace around the 50k mark.

It seems that the procedure to replace the cam chain wear pads are the same steps that are used to replaced the IMS: mentioned here numerous times "lock the crank at TDC, lock the cams (with the special tool), then remove the variocam actuators and replace the wear pads" perhaps with the upgraded LN billet machined ones.

Question: Is the tool to lock the cams the only special tool required? Is this a straight forward job that can be accomplished by a DIY with standard tools?

.

I was refering to the CAM chain wear pads for the 97-02 Box engines seen here: here:

this was changed in the 02 996 3.6 & 03 986 3.2 & later so no worries for you there.

Below is the oem IMS to crank chain tensioner paddle you are refering to at the far right side of the picture. You can see the round wear pad that contacts the tensioner plunger & you can inspect for wear by removing the Tensioner.

[Gilles]

Originally Posted by BYprodriver

Below is the oem IMS to crank chain tensioner paddle you are refering to at the far right side of the picture. You can see the round wear pad that contacts the tensioner plunger & you can inspect for wear by removing the Tensioner.
.jpg[/img]

BYprodriver:

Thank you for the pictures, it is possible to remove and replace the IMS to crank chain tensioner paddle with the engine on the car?

Looking at your picture, it seems that you have to split the engine case to remove the tensioner paddle is this correct?

.

[BYprodriver]

Originally Posted by Gilles

BYprodriver:

Thank you for the pictures, it is possible to remove and replace the IMS to crank chain tensioner paddle with the engine on the car?

Looking at your picture, it seems that you have to split the engine case to remove the tensioner paddle is this correct?

.

The engine case must be split to remove the paddle, but you can inspect the main wear point by removing the tensioner.