Cam deviation at 6 after VC pads done

[ike84]

My understanding of the measurements is that they should be taken at idle with the car hot, but should not fluctuate widely with rpm variations unless there's an actuator issue (then you'll see huge variations)

I think there are a few sentiments about these numbers - first is that the trend is more important than the actual number (stable over time vs progressively worsening) and that unless a cel is on then not to worry. Second is that anything greater than 2 deg is enough to start causing mechanical issues (dme changes fuel trims) and should be addressed.

If you know that your pads and tensioners are good, then you're probably fine. You may have a bad sensor and it.might be worth swapping the sensors.from side to side to see if the readings change. If they do you have your answer.

If you swap sensors and still get 6 on bank 1, it may be mistimed. I don't know what the right answer there is though. I say that because one of the main reasons behind the "ignore it unless you get a cel" is because supposedly these cars will come off the line with significant timing deviations, although I've never seen a hard example to quote. 9 is the threshold for the cel, and 6 shouldn't put you in danger of piston/valve damage, so as long as your hardware is good and performance is good you can easily invoke the old "enemy of good" philosophy.

One thing I find fascinating - I know people make a big deal over these numbers, and rightly so considering the consequences of pad failure. With that being said, ROW cars (and that includes those in the fatherland) don't even register cam deviation on bank 2. So clearly porsche never wanted to put much emphasis on these numbers from the get go. Whether that was an oversight though (and you could very well argue that it is) is not clear.

Hope this helps.


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[DarrenD]

Thanks for the well written reply ike84, I certainly appreciate you taking the time. It seems odd that the timing would be off based on the fact that I used the recommended Porsche timing tool and spun the motor many, many times to verify it was perfect. I have fired both solenoids with my Durametric and both caused the same result, a noticeable change in the idle quality. I'm not sure what else it could be?
The measurements were done hot, at idle.
I have "heard" that it's possible those were the numbers when it came from the factory, not sure I believe it but maybe? I will certainly keep an eye on things.
The car runs so well and so much better than before I did all the work I can't imagine there's an issue, but the number's don't lie...or do they?

[flmont]

What did the pads look like, worn down or not to bad,.?

[blue62]

Have you looked at your fuel trims?
Have you compared fuel trims before the work with after?
Have you compared fuel trims bank1 vs bank2 ?
Positive fuel trim on bank1 could point to the cam timing on that bank not being spot on.





















d

[DarrenD]

Originally Posted by blue62

Have you looked at your fuel trims?
Have you compared fuel trims before the work with after?
Have you compared fuel trims bank1 vs bank2 ?
Positive fuel trim on bank1 could point to the cam timing on that bank not being spot on.

d

Thank you for this, I had no idea I could check it that way. Great idea.

[blue62]

Originally Posted by DarrenD

Thank you for this, I had no idea I could check it that way. Great idea.

As cam timing gets farther and farther from the Ideal set point (deviation).
The engine will begin to use more fuel.
It may be very slight, but you may see it in the fuel trims.
Since it is four cams and two banks you can compare bank 1 to bank 2.
I think you stated that bank 2 has zero or very little deviation.
If bank 1 is at I think you said 6?? you should see it in positive fuel trims on that bank.
Long term trims is where it will show up.

[DarrenD]

Originally Posted by flmont

What did the pads look like, worn down or not to bad,.?

They were well worn.