Engine noise diagnose assistance - Possible vario cam actuator/pad/chain issue?

[bg305]

Originally Posted by blue62

If you are attempting to isolate a sound.
Use an automotive stethoscope, or a length of hose.
Hold one end of the hose to your ear then move the other end of the hose around the engine to locate the sound.
Ok I know access can be difficult.
Also if it only happens at certain RPM's then you need a helper.
But it is actually very effective.
If the sound is Vario Cam chain,pad related you should be able to isolate the sound to which bank it is without to much trouble.

Looking at your Cam angles it is showing a 25 Degree change at change over.
25 Degree change in Cam angle when the VarioCam actuator triggers is spot on.
I forget what RPM that is supposed to happen but somewhere around 1500 RPM is when they kick in. Then back out at around 5500 RPM.

This is a good idea, I am going to give it a try if I can locate a helper.. would be nice to see if it is bank 1 or 2. Bank 2 has the big deviation, but it sounds like it is coming from bank 1.

Also,

Originally Posted by blue62

25 Degree change in Cam angle when the VarioCam actuator triggers is spot on.

Do you know if I would expect these numbers to be off more if pads had been compromised / deteriorated badly or is just telling me that the actuators themselves are doing their jobs cleanly?

[blue62]

Originally Posted by bg305

This is a good idea, I am going to give it a try if I can locate a helper.. would be nice to see if it is bank 1 or 2. Bank 2 has the big deviation, but it sounds like it is coming from bank 1.

Also,



Do you know if I would expect these numbers to be off more if pads had been compromised / deteriorated badly or is just telling me that the actuators themselves are doing their jobs cleanly?

The 25 degrees is how much the cams advance when the Variocam actuator kicks in.
If your starting out with 9 degrees of negative Cam deviation due to the pads being compromised or worn. Then when your Varocam system kicks in your really only getting 16 degrees of advance on the Cams because you are starting out 9 degrees retarded.
I hope that makes sense.

The actuators seem like they are working fine. The issue is you are starting with the 9 degrees of late cam timing=deviation.

[bg305]

Originally Posted by blue62

The 25 degrees is how much the cams advance when the Variocam actuator kicks in.
If your starting out with 9 degrees of negative Cam deviation due to the pads being compromised or worn. Then when your Varocam system kicks in your really only getting 16 degrees of advance on the Cams because you are starting out 9 degrees retarded.
I hope that makes sense.

The actuators seem like they are working fine. The issue is you are starting with the 9 degrees of late cam timing=deviation.

Yes it does, and just to be sure.. my actual cam angle readings ~24-25 degrees do not take the deviation numbers into account. (if they did my bank 2 should be reading around 16 degrees like you said). I just want to check that the readings the DME are giving would be expected or if bank 2 should show 16 degrees. I still have doubts about my data given the tune on my car, and lack of error code given the -9.27 deviation.

[blue62]

Originally Posted by bg305

Yes it does, and just to be sure.. my actual cam angle readings ~24-25 degrees do not take the deviation numbers into account. (if they did my bank 2 should be reading around 16 degrees like you said). I just want to check that the readings the DME are giving would be expected or if bank 2 should show 16 degrees. I still have doubts about my data given the tune on my car, and lack of error code given the -9.27 deviation.

I looked at your video again.
Actual cam angles displayed on your scanner are under 1degree on both banks actually they are within .20 of each other. while your RPM is in the 700 RPM range.
When you hit the kick over point both banks are at 23-24 Degrees of Actual cam angle.
Seems odd to me.
Seems that with deviation of 2&9 that there should be a bigger difference in actual cam angle readings from one bank to the other.

[blue62]

Hey BG305
I have both a Foxwell and a Durametric I will hook both up to my 2000S and see what they read for actual cam angles, differences from bank to bank whatever and get back to you. I have a little excess Cam deviation on one of the banks.
See if we have similar readings.
Won't get to it tell Saturday or Sunday though.

[bg305]

Originally Posted by blue62

Hey BG305
I have both a Foxwell and a Durametric I will hook both up to my 2000S and see what they read for actual cam angles, differences from bank to bank whatever and get back to you. I have a little excess Cam deviation on one of the banks.
See if we have similar readings.
Won't get to it tell Saturday or Sunday though.

No problem, thank you for checking!

[blue62]

Ok I think I have it figured out.
First I was wrong on a point or two
Camshaft deviation and Camshaft angle readings are unrelated.
Cam deviation is expressed in degrees of crank rotation.
Actual cam angle is also expressed in degrees of crankshaft rotation.

Actual cam angle is what the DME expects to see.

So with Variocam actuator off the DME expects to see O degrees of Cam angle
With Variocam actuators on the DME expects to see 25 Degrees of Cam angle
That explains why you see both your cams at or very near 0 degrees at 700 RPM
And very near 25 degrees at the trigger point.

So Cam deviation is an adaptation value.

Where as Cam angle is degrees of Cam advance (exhaust cam only I think) when the Variocam system is active.
Seems that the "Actual cam angle" readings are related to the operation of the Variocam system only.

Thats my current understanding.
Sorry about any confusion from my previous post.

[bg305]

Originally Posted by blue62

Ok I think I have it figured out.
First I was wrong on a point or two
Camshaft deviation and Camshaft angle readings are unrelated.
Cam deviation is expressed in degrees of crank rotation.
Actual cam angle is also expressed in degrees of crankshaft rotation.

Actual cam angle is what the DME expects to see.

So with Variocam actuator off the DME expects to see O degrees of Cam angle
With Variocam actuators on the DME expects to see 25 Degrees of Cam angle
That explains why you see both your cams at or very near 0 degrees at 700 RPM
And very near 25 degrees at the trigger point.

So Cam deviation is an adaptation value.

Where as Cam angle is degrees of Cam advance (exhaust cam only I think) when the Variocam system is active.
Seems that the "Actual cam angle" readings are related to the operation of the Variocam system only.

Thats my current understanding.
Sorry about any confusion from my previous post.

No worries! Thank you for weighing in, it was really helpful! I am trying to understand it as best I can as well.

I called around to local shops, found one that is taking it in next Wednesday. Described the issue and the mechanic said he would scope it and we would go from there. Assuming it is the guides I am going to ask them to check to see if the ims is single / dual row and possibly do that if it is single, clutch as well.

I will update with a resolution when I have one..