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It takes a sharper mind than mine to answer that one. I'll look for my deviation and post it for you though.
Mine was based on taking it apart to inspect. I knew I was going to pin both when it happened regardless of whose tab it was on, so it was an easy decision for me.
Edit: found mine:
Hey Scott...
Is that image of camshaft angle reading when it was bad, or normal?
Just curious for clarity...
BTW...How is your car running now after all your work? I imagine pretty well.
Is that image of camshaft angle reading when it was bad, or normal?
Just curious for clarity...
BTW...How is your car running now after all your work? I imagine pretty well.
Thanks!
DC
DC, that's an "after" shot. I'm not sure how good or bad that is. Kevin could probably weigh in and tell us.
As for how my car runs, let me put it this way. I'm on my 5th Mezger motored 911 (3 996tt's, 1 993tt, and 1 997tt) all with similar mileage. This is by far the smoothest running of them all... and it's not even close.
Anything less than 6 degrees (either plus or minus) of cam deviation per bank is considered "in spec" by Porsche, I believe. Not sure what happens when it gets outside of that, maybe that's when the CEL gets tripped..
Not sure about the cam angle values..
Cincy's numbers under 1 degree for deviations on both banks would be considered quite good, I think..
Getting Scott's camshaft deviation numbers is/are very good.
There is a inside story about how Porsche has removed the chain tensioner "step" in the repair procedure. Please note: anyone that has this repair done, please ask the tech to use the 964 chain tensioner when cam timing your engine. Scott paid some extra labor to get it done>the results speak for themselves.
Getting Scott's camshaft deviation numbers is/are very good.
There is a inside story about how Porsche has removed the chain tensioner "step" in the repair procedure. Please note: anyone that has this repair done, please ask the tech to use the 964 chain tensioner when cam timing your engine. Scott paid some extra labor to get it done>the results speak for themselves.
I remember that now, Kevin's right. They timed my engine the "new" way, and I asked them to re-do it the "old" way. The tech didn't mind, but the shop foreman was very unhappy. The engine was still out, so we don't have numbers for the new timing method vs. old, but I trusted Kevin on this one... doesn't appear to have been a bad decision.
As far as "new" vs "old," the manuals state different methods to time them. The 997 manual's version doesn't use some special tools that the 964/993/996's do, so there seems to be some confusion on it. Mine was originally timed as a 997, but was re-timed as a 964.
My tech after talking to us about it agreed that he would never time another 997 the new way again...
My car is .3 to .4 across the board. Engine guy said its the most dialed in he's been so far. I should note he was this accurate both times he put mine back together
My car is .3 to .4 across the board. Engine guy said its the most dialed in he's been so far. I should note he was this accurate both times he put mine back together
Be careful here. Understand what the deviation actually is. All you are reading this the trigger wheel referenced to the crankshaft on both sides of the engine. These are production based engines so the manufacturing tolerances are quite large. The only way to absolutely know your cams are set exactly the same each side is to "time" them with Indicators at full lift or full overlap on a lobe and split the nose each side to get a true reading of dead center on the nose.
This after you have checked that the lobes are all at the same separation. I can tell you there is often a big difference between the trigger wheel position to the lobes and the lobe separations on different camshafts. Add in the fact that most engines run zero lash on the follower (not by design) the cam geometry is off, which affects the performance.
I guess it comes down to how close do you want it.
It takes a sharper mind than mine to answer that one. I'll look for my deviation and post it for you though.
Mine was based on taking it apart to inspect. I knew I was going to pin both when it happened regardless of whose tab it was on, so it was an easy decision for me.
Edit: found mine:
is this something the dealer will pull up in their analysis? Been 2 days and haven't heard anything on my car yet. I should hear from them today on the status.
is this something the dealer will pull up in their analysis? Been 2 days and haven't heard anything on my car yet. I should hear from them today on the status.
I could be wrong, but I don't think these readings will show if you have an issue like the one described in this thread. They can do the reading from the PIWIS, but I don't think it's a smoking gun. However, it is something to make sure you know the readings, because it helps to know how much the cams are fighting each other (creating loss) in your motor.
Anything less than 6 degrees (either plus or minus) of cam deviation per bank is considered "in spec" by Porsche, I believe. Not sure what happens when it gets outside of that, maybe that's when the CEL gets tripped..
Not sure about the cam angle values..
Cincy's numbers under 1 degree for deviations on both banks would be considered quite good, I think..
Are the numbers posted in degrees? So anything over .6 is not in spec?
Originally Posted by CincyScott
I could be wrong, but I don't think these readings will show if you have an issue like the one described in this thread. They can do the reading from the PIWIS, but I don't think it's a smoking gun. However, it is something to make sure you know the readings, because it helps to know how much the cams are fighting each other (creating loss) in your motor.
hmm i'll have to address this with them if it comes up. I finally heard from the dealer and they are doing the same thing they did last time, swapping cam sensors to see if the sensor or cam is bad. $780 worth of work lol. I have no idea where the cam sensors, but i'm surprised it's 5 hours worth of work. Seems like a lot. They have to put at least 60 miles on the car too.... so I guess the foreman is going home with my car tonight, he better be nice.
Are the numbers posted in degrees? So anything over .6 is not in spec?
Anything over six FULL degrees is out of spec, not .6. That's per SAABIN, I don't know, but I trust him.
hmm i'll have to address this with them if it comes up. I finally heard from the dealer and they are doing the same thing they did last time, swapping cam sensors to see if the sensor or cam is bad. $780 worth of work lol. I have no idea where the cam sensors, but i'm surprised it's 5 hours worth of work. Seems like a lot. They have to put at least 60 miles on the car too.... so I guess the foreman is going home with my car tonight, he better be nice.
It appears that the dealer is trying really hard for this to be electrical.
Anything over six FULL degrees is out of spec, not .6. That's per SAABIN, I don't know, but I trust him.
It appears that the dealer is trying really hard for this to be electrical.
spoke to Kevin, huge help! Porsche's still saying they try to diagnose the problem as electrical to avoid going big with the camshaft having to be replaced. They said the sensor could be replaced and could still have the problem.
It's just difficult to get them to diagnose the problem as definitively being the camshaft without going in and pulling it. So they are trying to see if they can fix it without the cam being the problem. I told them i just don't want them doing the same thing twice and having the issue after another 10k miles. They should say to the insurance company that this is the second time and that the cam needs to be replaced. That's why I have coverage and it should get fixed properly. They stated it could be the oil since it's due for a change...
I was quoted 2100 dollars for the Engine and Powertrain warranty only. Which should cover the camshaft issue.
I'm about to renew my coverage, just realized that powertrain covers camshafts, but the gold plus covers the cam sensors (electronics). So if someone has this issue and the code kicks, the policy holder with just powertrain will likely have to pay for the investigative probing to diagnose the cams actually being the issue. Food for thought.
06-13-2016, 09:50 PM
