Go Back   6speedonline.com Forums > Porsche (Present) > 996 Turbo / GT2
Sign in using an external account
Register Forgot Password?

996 Turbo / GT2 Turbo discussion on previous model 2000-2005 Porsche 911 Twin Turbo and 911 GT2.
Sponsored By Vivid Racing

Camshaft Deviation Angles?

Reply
 
 
 
 
Thread Tools Search this Thread Rate Thread Display Modes
  #1  
Old 12-06-2011, 07:29 AM
Registered User
 
Join Date: May 2011
Posts: 39
Rep Power: 5
Pmafia will become famous soon enough
Camshaft Deviation Angles?

Does anyone know why camshaft deviation angle, as read by a Durametric, is an indicator of engine health? Supposedly it is the deviation between the camshafts and the crank.

I read somewhere a while back that the acceptable range is 0-6 total absolute value of the two camshaft deviation angles with 0 being perfect and 6 at the upper limit.

Is it an indicator of how much the timing chain has stretched? Can anyone chime in on this?
Reply With Quote
  #2  
Old 12-06-2011, 08:15 AM
jpflip's Avatar
Registered User
 
Join Date: Mar 2008
Location: Montreal Canada
Age: 59
Posts: 2,135
Rep Power: 158
jpflip has a reputation beyond reputejpflip has a reputation beyond reputejpflip has a reputation beyond reputejpflip has a reputation beyond reputejpflip has a reputation beyond reputejpflip has a reputation beyond reputejpflip has a reputation beyond reputejpflip has a reputation beyond reputejpflip has a reputation beyond reputejpflip has a reputation beyond reputejpflip has a reputation beyond repute
I don't know the values but an important thing is to get a reading change and equal on both side. This is because of the weakness of a seal on the camshafts. The oil under pressure coming from the camshaft solenoid is normally going to the vario cam to advance the cams. But if this seal failed there will be a malfunction of the vario cam. Look at the post from Porsche Doc about this failure: http://forums.rennlist.com/rennforum...e-p1325-2.html
__________________
2002 996TT seal gray... Carbon fiber package. Agency power diverter valves + silicone hoses, 15mm spacers on all 4 wheels, 997 shifter, UMW tune and Kline exhaust, RS engine mounts.
Reply With Quote
  #3  
Old 12-06-2011, 08:34 AM
Registered User
 
Join Date: May 2011
Posts: 39
Rep Power: 5
Pmafia will become famous soon enough
jpflip, your thinking the "Actual Camshaft Angle" which at idle is 0 and advances to 30 over a certain RPM. I'm talking "camshaft position deviation" which stays pretty much constant. There is a slight change once the engine is warmed up.
Reply With Quote
  #4  
Old 12-06-2011, 08:58 AM
jpflip's Avatar
Registered User
 
Join Date: Mar 2008
Location: Montreal Canada
Age: 59
Posts: 2,135
Rep Power: 158
jpflip has a reputation beyond reputejpflip has a reputation beyond reputejpflip has a reputation beyond reputejpflip has a reputation beyond reputejpflip has a reputation beyond reputejpflip has a reputation beyond reputejpflip has a reputation beyond reputejpflip has a reputation beyond reputejpflip has a reputation beyond reputejpflip has a reputation beyond reputejpflip has a reputation beyond repute
Sorry Pmafia you're right. Camshaft angle was what I was loging and not deviation.... I will definitively learn something from this question. Let's hope somebody will get an answer...

For a Boxter but JFP explanation is interesting...http://forums.pelicanparts.com/boxst...deviation.html
__________________
2002 996TT seal gray... Carbon fiber package. Agency power diverter valves + silicone hoses, 15mm spacers on all 4 wheels, 997 shifter, UMW tune and Kline exhaust, RS engine mounts.

Last edited by jpflip; 12-06-2011 at 09:04 AM.
Reply With Quote
  #5  
Old 12-06-2011, 09:49 AM
Registered User
 
Join Date: May 2011
Posts: 39
Rep Power: 5
Pmafia will become famous soon enough
jpflip, that explanation does make sense. I would think it would have something to do with the timing chains. Just for information purposes my camshaft deviation angle for bank 1 was 0 and for bank 2 was -.9, the car has 60k miles. Looks really good to me from what I have seen. Lets hope someone experienced engine builders can offer some input so we can both learn something.
Reply With Quote
  #6  
Old 12-06-2011, 09:56 AM
jpflip's Avatar
Registered User
 
Join Date: Mar 2008
Location: Montreal Canada
Age: 59
Posts: 2,135
Rep Power: 158
jpflip has a reputation beyond reputejpflip has a reputation beyond reputejpflip has a reputation beyond reputejpflip has a reputation beyond reputejpflip has a reputation beyond reputejpflip has a reputation beyond reputejpflip has a reputation beyond reputejpflip has a reputation beyond reputejpflip has a reputation beyond reputejpflip has a reputation beyond reputejpflip has a reputation beyond repute
Always like to read that kind of information. Thanks for starting this subject Pmafia! We learn something new every day ;-)
__________________
2002 996TT seal gray... Carbon fiber package. Agency power diverter valves + silicone hoses, 15mm spacers on all 4 wheels, 997 shifter, UMW tune and Kline exhaust, RS engine mounts.
Reply With Quote
  #7  
Old 12-06-2011, 12:16 PM
Registered User
 
Join Date: Mar 2011
Location: England
Posts: 61
Rep Power: 7
And996tt has a spectacular aura aboutAnd996tt has a spectacular aura about
Some info in this recent thread about camshaft deviation

anyone with a durametric, a 996t, and ten minutes....

Rennfabbs car was showing 11 degree deviations after a mistake timing the cams and this was enough to throw codes and prevent the cam advance system working.

And
Reply With Quote
  #8  
Old 12-06-2011, 03:24 PM
Registered User
 
Join Date: May 2011
Posts: 39
Rep Power: 5
Pmafia will become famous soon enough
^^^ In that thread, I think winnigt2 hit it right on the head.

"a large deviation shows either timing chains lengthened or cam shaft sensor not in order"
Reply With Quote
  #9  
Old 12-06-2011, 05:48 PM
Tim941NYC's Avatar
Registered User
 
Join Date: Jul 2010
Location: Long island NY
Posts: 3,185
Rep Power: 306
Tim941NYC has a reputation beyond reputeTim941NYC has a reputation beyond reputeTim941NYC has a reputation beyond reputeTim941NYC has a reputation beyond reputeTim941NYC has a reputation beyond reputeTim941NYC has a reputation beyond reputeTim941NYC has a reputation beyond reputeTim941NYC has a reputation beyond reputeTim941NYC has a reputation beyond reputeTim941NYC has a reputation beyond reputeTim941NYC has a reputation beyond repute
Every motor I have taken apart I have in stalled the cam plates and check the timing before dis assembly. Not one was on the money. 5000 mile motor right out to 80,000 miles. My motor never changed after install by no matter how much time you spend on timing the cam they never end up dead on. It must be something with the intake vario sprocket having some lose tolerances.
__________________
A man with a gun is a citizen. A man with out a gun is a subject.

HBK 1XXX
Reply With Quote
  #10  
Old 12-06-2011, 06:19 PM
Registered User
 
Join Date: Aug 2011
Location: New York, USA
Posts: 267
Rep Power: 17
RennFab is a glorious beacon of lightRennFab is a glorious beacon of lightRennFab is a glorious beacon of lightRennFab is a glorious beacon of lightRennFab is a glorious beacon of light
+1 to what Tim said. Used to own the factory tooling (thieves!!!!) and do remember after discussions with him that I too never found one motor to be dead on during service work.

My post(linked about) definitively showed that the cam deviation of ~11 degrees per bank was sufficient to throw the codes. The DME referenced this deviation immediately and put the variocam into a state of shutdown. The large deviation was caused by the crankshaft not being in proper relation to the camshafts(proper TDC) before the cam bolts were set to their pretorque of 22ftlbs. Subsequently re-timing the cams resulted in cam deviations of less than a 1/4 of a degree(.02 and .08 degrees at warm idle actually). This being set via TDC indicator and a degree wheel looking for actual piston dwell.

Camshaft deviation should not change anything more than a few tenths of a degree. The cams are physically friction locked in this position. They will deviate a very tiny bit based on pressure application of the hydro tensioners as the oil warms, oil pressure drops, and as the overall dimensions of the motor change as it warms up.

Major deviation could indicate one of many possible mechanical failures from stretched/broken chains, failed chain ramps(sliders) or tensioners, slipped cam gears, sheared key on the crank IMS, etc, etc.
Reply With Quote
Old 12-06-2011, 06:19 PM
 
 
 
Reply

Tags
2000, 911, 996, acceptable, angle, boxster, cam, camshaft, deviation, engine, porsche, range, timing, turbo, variocam


Thread Tools Search this Thread
Search this Thread:

Advanced Search
Display Modes Rate This Thread
Rate This Thread:

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 Off
Trackbacks are Off
Pingbacks are On
Refbacks are Off


Join 6SpeedOnline
Visit our Sponsors

All times are GMT -6. The time now is 03:42 PM.


Secure Backup

SEO by vBSEO 3.5.2