Go Back   986 Forum - for Porsche Boxster & Cayman Owners > Porsche Boxster & Cayman Forums > Performance and Technical chat

Reply
 
LinkBack Thread Tools Display Modes
Old 09-29-2014, 07:21 PM   #1
Registered User
 
jaykay's Avatar
 
Join Date: Sep 2009
Location: toronto
Posts: 2,276
Exclamation Durametric Cam Shaft Deviation Change

I ran some Durametric work sessions for cam shaft deviation and saw a change in deviation as the car warmed. Ahhhh have not seen this before and am properly freaked out! There were not fluctuating/dancing but they drifted. Pos.1 dev. drifted the most.

The files are attached; scroll through and have a look. The time stamp in the file names are indicative of first to last sessions and cold to warm.

I could see pos. 1 vary from -1.59 all the way to -2.05 degrees
and pos. 2 vary from -3.69 to -3.8 degrees. Session 3 file: 2014_09_29_22_03_20 shows a lot of change starting at line 489!

The readings eventually stabilized in the later sessions close to 86 C at: pos. 1>-2.05pos. 2>-3.8

Is this: a real cam drive issue; a sensor issue; a normal senor warm up problem; Durametric sampling problem???

Edit: apologies the files are not permited; I will have to email them or cut and paste some of the data
__________________
00 986 S....with a few tweaks

Last edited by jaykay; 09-29-2014 at 07:29 PM. Reason: why cant excel files be attached?
jaykay is online now   Reply With Quote
Old 09-29-2014, 09:07 PM   #2
Registered User
 
thom4782's Avatar
 
Join Date: Sep 2010
Location: Foster City CA
Posts: 1,074
My understanding is that the cam shaft deviations can change as the variocam warm up. Once the engine is up to operating temperature, check to see is the deviations are steady. Those readings are the ones that count
thom4782 is offline   Reply With Quote
Old 09-29-2014, 11:43 PM   #3
Registered User
 
Steve Tinker's Avatar
 
Join Date: Dec 2008
Location: Queensland, Australia
Posts: 1,522
My camshaft deviation alters +/- 0.2 deg from cold to hot.
As I understand it, that as long as the running (hot) deviations are not more than 6 deg max you are within spec.
As a side note ROW cars gives you camshaft deviation reading on Bank 1 only, while US spec cars give you deviations on both bank 1 & 2, so I have no idea what my ROW spec car's bank 2 deviations are....I wonder why??
__________________
2001 Boxster S (triple black). Sleeping easier with LN Engineering/Flat 6 IMS upgrade, low temp thermostat & underspeed pulley.
2001 MV Agusta F4.
Steve Tinker is offline   Reply With Quote
Old 09-30-2014, 04:11 PM   #4
Registered User
 
jaykay's Avatar
 
Join Date: Sep 2009
Location: toronto
Posts: 2,276
Thanks for the feedback guys....I had never seen that temperature drift before.

I replaced the chain tensioners with new ones....and lost my oil in the process so that was changed too.

I still saw a drift in cam dev. up to 80 C. They seemed to stabilize there after. I noticed that actual cam shaft angle does dance continuously; it seems that the deviation angle must be sampled in part from cam angle
The deviations seem to stabilize at pos1.> -2.00 and pos2.> 3.72 which is an improvement, but during the warm up I did see pos1.> -2.19! So on the surface it seems that the new tensioners did help bring things closer to ideal. The engine feels more like a tight new engine and the rattle is gone....even with my interior stripped. It feels great.

I found a lot of what I believe to be variocam pad material in the oil filter (no metal to speak of):



I am thinking that my lazy old tensioners have contributed to more aggressive wear on the vario pads due chain "whip" at lower speeds (I believe they actuate just below 3000 rpm). I only dip below 3K when I have to
__________________
00 986 S....with a few tweaks

Last edited by jaykay; 09-30-2014 at 04:33 PM.
jaykay is online now   Reply With Quote
Old 09-30-2014, 07:00 PM   #5
Engine Surgeon
 
Join Date: Aug 2008
Location: Cleveland GA USA
Posts: 2,424
Quote:
Originally Posted by jaykay View Post
I ran some Durametric work sessions for cam shaft deviation and saw a change in deviation as the car warmed. Ahhhh have not seen this before and am properly freaked out! There were not fluctuating/dancing but they drifted. Pos.1 dev. drifted the most.

The files are attached; scroll through and have a look. The time stamp in the file names are indicative of first to last sessions and cold to warm.

I could see pos. 1 vary from -1.59 all the way to -2.05 degrees
and pos. 2 vary from -3.69 to -3.8 degrees. Session 3 file: 2014_09_29_22_03_20 shows a lot of change starting at line 489!

The readings eventually stabilized in the later sessions close to 86 C at: pos. 1>-2.05pos. 2>-3.8

Is this: a real cam drive issue; a sensor issue; a normal senor warm up problem; Durametric sampling problem???

Edit: apologies the files are not permited; I will have to email them or cut and paste some of the data
Do you have anything tied in with the oiling system at all?
__________________
Jake Raby/www.flat6innovations.com
IMS Solution/ Faultless Tool Inventor
US Patent 8,992,089 &
US Patent 9,416,697
Developer of The IMS Retrofit Procedure- M96/ M97 Specialist
Jake Raby is offline   Reply With Quote
Old 09-30-2014, 08:08 PM   #6
Registered User
 
jaykay's Avatar
 
Join Date: Sep 2009
Location: toronto
Posts: 2,276
Quote:
Originally Posted by Jake Raby View Post
Do you have anything tied in with the oiling system at all?
The car is a 5 chain, 2000 S running 5W40.

It does have a deep sump but other than that there are no oil system modifications.
__________________
00 986 S....with a few tweaks
jaykay is online now   Reply With Quote
Reply


Thread Tools
Display Modes

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is On
Trackbacks are On
Pingbacks are On
Refbacks are On




All times are GMT -8. The time now is 03:22 PM.


Powered by vBulletin® Version 3.8.7
Copyright ©2000 - 2019, vBulletin Solutions, Inc.
Content Relevant URLs by vBSEO 3.6.0
Copyright 2018 Pelican Parts, LLC - Posts may be archived for display on the Pelican Parts Website -    DMCA Registered Agent Contact Page