Help with cam deviations - 986 Forum - The Community for Porsche Boxster & Cayman Owners

dlud · 02-27-2018, 04:53 PM

I have a 2000 S with 66k with recent IMS upgrade. The car runs great and no codes. I recently bought a Durametric and ran the program to see if there was anything to be concerned about. Turns out that after a thorough warmup bank 1 is showing a cam deviation of 7.08. Bank 2 shows 5.33. At idle cam angles are 2.48 and .92 for banks 1 and 2 respectively. Running rpms up over 3000 results in cam angles of 22.16 and 23.67 for 1 and 2 respectively. I ran this by my local independent and he wasn't too concerned and suggested a wait and see approach since I had not found plastic shards in the oil (yet).
Based on all I have seen and read it looks like variocam tensioner pads. But I wonder if it might just be that bank 1 is and has been out of time. Is there any benefit to simply retiming the bank 1 cams, are tensioner pads a better diagnosis and is there any other likely explanation?

Quadcammer · 02-27-2018, 05:02 PM

Im confused. You got 3 sets of numbers but im not clear what the test parameters are for each

Meir · 02-27-2018, 05:05 PM

Not sure if I completely understand your concern.
Cam deviation should be measured when the engine is at operating temperature, and running at idle.
Based on your following statement:
“At idle cam angles are 2.48 and .92 for banks 1 and 2 respectively”
You are well within spec (-6 +6).

dlud · 02-27-2018, 05:12 PM

The top two numbers are cam deviation at idle for banks 1 and 2. The third and fourth numbers are actual cam angles (not the deviations). Both screen shots were taken with the car well warmed up.
The second screen shot was reflecting the "actual" cam angle once the variocam kicked in (rpm over 3000).
I thought that the +/- 6 number we are concerned about is the "cam deviation" not the actual cam angles. (?)

thom4782 · 02-27-2018, 05:45 PM

Cam deviations should be between -6/+6. One of yours is outside the range and likely due to a worn variocam pad. At some point, you'll get a check engine light when the deviation becomes higher.

Actual angles look ok, I forget at what RPMs the variocams kick in, but 3000 rpms is in the range.

dlud · 02-27-2018, 06:11 PM

And I suppose there is really no way to know if it is variocam pads vs something else short of actually pulling them out. I was wondering (maybe hoping) that somehow the bank one cam was just mistimed and could simply be re-timed.

NewArt · 02-28-2018, 07:55 AM

Pretty sure that this is just pad wear. You won't get a cel before about 9 or 10. Pads need to be changed but it's not urgent. Within 6 is spec

dlud · 02-28-2018, 07:59 AM

Thanks. I'll do it now. No sense waiting.

dsallean · 02-28-2018, 10:24 AM

dlud if you are planning on doing it yourself it's not a job for the faint of heart. It can be done...I did it with the engine in the car. And I did it because I had debris in the filter. But if I had to do it again I might just pay the indy and let them do it.

dlud · 02-28-2018, 11:34 AM

dsallean: good advice. Still wringing my hands over which way to go. For other reasons I'm pulling the airbox out anyway so that should help on the 4-6 side. Did you pull your exhaust manifolds? Or how about the aluminum support members running to the transmission?

dsallean · 02-28-2018, 01:41 PM

dlud: I pulled the transmission supports and lowered the engine a little at the front, supported from the top with an engine support bar and from the bottom with a floor jack. I didn't remove the exhaust manifolds and was able to do it by just dropping the engine and shifting it slightly while r & r. Replacement would be straightforward with the engine removed. I have removed engines before...but I was told that Indy's don't remove the engine to perform this service so I thought I would give it a go.

Also, the airbox was not in my way.

NewArt · 02-28-2018, 02:49 PM

When I did mine, I dropped the engine. It was on my previous car which was a tip. I left the transmission attached to the motor and dropped them together. I don’t imagine that the manual transmission is any different (correct me if I’m wrong). If I were to do it again, I’d probably do it the same way. Life is so much easier with the engine out of the car!

dlud · 02-28-2018, 05:13 PM

NewArt: thanks. It looks like the 1-3 side will be a breeze on my car. 4-6 not so much. I may regret it but I'm going to try to complete the job with the motor in the car. It looks to me that the 4-6 side would be a lot easier without the airbox. Since I'm eventually going to put the 987 airbox in and it is sitting in my garage the 986 airbox may be gone in short order.

NewArt · 02-28-2018, 05:34 PM

Well, it’s certainly doable. You might take dsallean’s suggestion and drop it a wee bit. Dropping the engine a few inches is easy as you don’t have to remove or undo a lot of stuff. This would also give you more room to install the larger airbox. That way you could avoid some of the problems that I had when I installed my 987 air intake system (see my airbox install videos in the diy section of this forum).

philou320 · 03-01-2018, 02:33 AM

I did mine with the engine on the car, no big deal

CBRacerX · 03-01-2018, 09:05 AM

I’ll be doing this job sometime in 2018. After viewing what’s required I’m sure it can be done with the engine in the car, as other posters have noted. But for my own sanity I’ll be pulling the engine and trans, it’s not that hard with a lift and hydraulic table.