Help evaluate camshaft deviation numbers

I scanned a car and came up with these numbers that were steady after driving for about 20 minutes prior to get the water and oil temps up. Watching the flat 6 prequalification video gets states that anything over 4 is cause for some concern. Does that mean +4 or -4 as well? I was wasn�t sure if he meant each cylinder from zero or deviation from each other. . A/C was on accidentally but I don�t know if that matters.

+/- 6 per bank. A -3 on bank 1 and a +3 on bank 2 are acceptable variances. These cam deviations are definitely upper range. Is this an engine with higher miles? Is this first time checked, so no trend data?

Thanks for the quick reply. Only 30k on the motor, and no previous readings. It�s a car I am thinking about buying. The IMS has not been replaced.

It�s not just the delta between the two banks (which is important and could tell you if one side is worn way more than the other), it�s also the total number relative to the crank/IMS, because of a possible wear item for chain rails and/or IMS tensioner pad. So my point is, your specs, while not too far apart between the cams - both banks are still off relative to the crank, which means the overall timing could still be affected.

Im watching the camshaft deviations since few years now. My car is now at 152 xxx kms and basicly never move from theses numbers (deviation not spec angle you should ignore in this picture) I wouldnt like to see theses numbers to far from "0" Operating temp, idle

Quotes source post: 16819622

Can someone confirm if idle is an appropriate rpm to take an accurate reading? I thought I read somewhere before that the engine needed to be fully warmed up (coolant and oil temps) and that the engine should be rev�d and stabilized at 4000rpms. Dunno and would love some clarity.

Hi Okay Im defenately not the best tech around here but from my experience the deviation never move from start-up and are always close to "0". The deviation will stay steady through the entire band. But Ive seen the deviation pass from -1.03 deg cold start (maximum ever) to -0.27deg hot start after warm-up. So I start the car cold outside temp 13deg C and deviation are the following: -1.03 deg Pos 1 0.88 deg Pos 2 After warm-up and restart -0.27 deg Pos 1 0.73 deg Pos 2 As you can see they are pretty much in the same ballpark. And that it though the entire band while the actual and spec angle fluctuate following the rpm's which are also very close to each other. Here 1-2 screenshots, but If you want I can send you the complete sheets I have. I take one sample per month each month at cold start-up, hot start-up after about 45mins ride and WOT 5000rpms Just for clarification: B= Rpm C=Deviation 1 D=Deviation 2 E=Actual angle Inlet 1 F=Actual angle inlet 2 G=Spec angle inlet 1 H=Spec angle inlet 2 Cold start 13deg C outside Operating temp hot start sheet showing 4000-5000rpms (-40 deg spec angle shows WOT) So I cant really give you technical advises other then the common timing chain/pads and IMS but I can provide data to this thread if needed.

I am not an expert, but I’m a good researcher due to my M96/97 paranoia: I can’t attribute who I learned this from, but it works for starting pretty much every engine timing, fuel or air test with Durametric (PIWIS has more test start parameters): warm temps and idle-range load with a/c on. Some tests will specify 680-760 rpm (so a/c on) and engine >-10C. The info I’ve found in the DME 7.8 tech manual (PIWIS) says for some tests 600-1200 rpm and engine temp >40C. Regardless of rpm, cam deviation should NOT change, even though cam actual position will change. The deviation number is showing how far the #1 or #2 intake cam lobe centerline has moved from “ideal”. OP - M Murphy touches on some points that would play if an IMS was suspect. This car shows parallel pattern which, to me, with only this data point, indicates timing chain rail pad wear or timing is off. Two things can be done. 1) Drop sump and check oil filter, pickup screens, mag drain plug for pad debris or metal. 2) Check cam timing. ‘While you’re in there’, scope the cylinder bores. If you think you want to buy this car, you might price in IMS and chain rail replacement cost.

My spec is 4* for a 5 chain engine. The factory spec is 6* for the allowables. We have seen cam timing jump during an IMSR procedure with figures beyond 4*. The factory spec was never in regard to an IMSR procedure, because they said that it couldn't be done.

i think car codes at +/-9. +/- 6 is the indicator that something is going south and time to have a look before it gets worse. since you have just started monitoring deviation, best to just take your current numbers as a baseline and monitor change from the baseline. if your car stays rock-solid at +/- 5 then don't sweat it. if numbers continue to deteriorate then get the work done. to understand what is happening, your car uses a chain between the intake and exhaust cams to modify valve operation. a solenoid pushes on pads that change tension in the chain. the pads deteriorate over time (typically due to 'chain rattle' on cold start-up; porsche actually upgraded the pad part # with harder pads) which alters the 'deviation' between the 'cams'. symptoms of this can be found at your next oil change in the form of small, hard, brown plasic bits in the oil filter (pieces of the deteriorating pad). if you are finding soft green rubber bits then the solenoid is starting to go. pads tend to wear evenly side to side resulting in relatively similar numbers for each bank, whereas a soleniod will fail on one side and provide skewed numbers side to side. the work is relatively expensive to get done (lots of 'while you are in there' stuff do do - pads, chains, solenoids, tensioners, etc.) and failure is not catastrophic (although i am sure i'll get dissenting opinions on this); i had a solenoid fail and my deviation went to -16; car still ran although timing was not optimal. so recommend just keeping an eye on it for now. otherwise, this is not an ims thing. i've read that an ims about to fail (ie, so bad that it is physically wobbling) will show up as big deviation fluctuations (as opposed to a steady deviation reading) however the 'wobble' state doesn't last too long before full failure and the odds of capturing it in a deviation reading pretty low (unless you get one of those guardian devices ...).