Timing, cam lobes, washed rings? What was it?

Oops. I don't see it either....

Dylan wrote: Oops. I don't see it either....

Could you please explain how to insert the original psdata file (or, does this site support them)?

You're right GeorG... It doesn't work. I also get an error message.
I'll ask onyx, website administrator.

Yeah, uploading them here may not be an option Would you mind trying to e-mail them to me?

wrenchturnsyou@gmail.com

Tyler wrote: Yeah, uploading them here may not be an option Would you mind trying to e-mail them to me?

wrenchturnsyou@gmail.com

I already did.

It would be nice if the forum would support these kind of files, don't you think :whistle: ?

Yes sir, we're actually looking in to that right now!

I got your e-mail, I'll post up some images momentarily.

Got some waveforms marked up, lets see how I did!

We can start with the presumably known good bank, bank two:

postimg.org/image/aj171rx7b/

To do this, you first need to know the rotational speed of the engine during the capture. You get this by measuring the time it takes to complete 720 degrees (from TDC compression back to TDC compression). It's written like this: 720 degrees/duration = rotational speed. In this case, it coincidentally took 720 ms to do one complete cycle, so our rotational speed is 1 degree/ms.

Then, measure the time from the first TDC to the event you want to know about. I picked out EVO (exhaust valve opening) as best I could, and fount that it opens at about 145 degrees after TDC. Or, 25 degrees before BDC.

Now we can look at bank one.

postimg.org/image/ljwc6spg7/

One complete cycle in this capture is 656.9 ms. 720 degrees/656.9 ms = 1.096 degrees/ms. Then, measure the EVO as best we can (used a filter to get a better view), and it shows up at 160 ms. 160.1 ms X 1.096 degrees/ms = 175 degrees after TDC.

There's variables here, of course. I didn't find EVO scientifically, just eyeballed for the lowest point in the expansion pocket. Still, 30 degrees is not insignificant. Then, with some help from Google Images, I was able to count the number of teeth on a camshaft sprocket, 48. One revolution of the camshaft equals two revolutions of the crank, so our math here looks like: 720 degrees/48 teeth = 15 degrees/tooth.

If I did all that right, then it seems that your Audi is off two teeth on bank one. Did ANY of that makes sense? 'Cause I'm kinda confused now, lol.

Tyler wrote: Did ANY of that makes sense? 'Cause I'm kinda confused now, lol.

:huh:

Just joking. It makes perfect sense. But why not use the features that pico has instead of breaking up the calculator?

Our "known good" cylinder 4, showed EVO at 35 degrees BBDC (like you said, not scientific) using the pico's automatic calculations.





While suspect bad (or worse) cylinder 1, showed EVO at 7 degrees BBDC (or close to that).





That's a 28 degree difference :ohmy:

GeorG wrote:

Tyler wrote: Did ANY of that makes sense? 'Cause I'm kinda confused now, lol.

:huh:

Just joking. It makes perfect sense. But why not use the features that pico has instead of breaking up the calculator?

Eh, just habits, mostly. I don't actually own a Pico scope, I just have the software so I can make use of other people's waveforms. The Snap-On scope I do have won't do the math for me, so I'm used to doing it manually

I am glad that the Pico automatic calculator agrees, though, means I did my math right! It's still looking like two cam teeth, assuming I was looking at the right image for this engine.

GeorG wrote: Our "known good" cylinder 4, showed EVO at 35 degrees BBDC (like you said, not scientific) using the pico's automatic calculations.

While suspect bad (or worse) cylinder 1, showed EVO at 7 degrees BBDC (or close to that).

That's a 28 degree difference :ohmy:

Mmmhh, Is it just me, or are we having trouble uploading GIF and PNG files too?

Cyl 1





Cyl 4

Yeah, the image uploader was giving us trouble earlier in the week, sorry 'bout that.

I think the in-cylinder ended up being pretty conclusive here. Especially nice when you're in between the customer and another shop.