Reading Cam Deviation Values - 986 Forum - The Community for Porsche Boxster & Cayman Owners

TTGator · 09-26-2021, 10:58 AM

Made another DIY video on reading the values after changing my tensioners. Still going to do the rail guides, but luckily it looks like I have a bit of time.

https://youtu.be/37DhdBtSwkA

Zordrack · 10-03-2021, 09:52 AM

Looking forward to the chain guide video.
Have a bad feeling that just became prescient for me.

TTGator · 10-03-2021, 11:49 AM

Thanks! Pretty sure it is for most 986’s

Zordrack · 10-03-2021, 01:44 PM

Already subbed

Truly much appreciated.

gabedrummin · 10-03-2021, 02:38 PM

Camsaft deviation is not measured at ide .I was told to have a fully warmed engine at operationg temp and rev the motor to 4k and hold the rpm there . The auctutors do operate till above 2500 rpm ?

TTGator · 10-03-2021, 02:58 PM

I was told to do it at idle. And “ Cam actuator kicks in around 1700 rpm and off around 3000 rpm so the numbers will change in that range ”. ��****♂️

Stl-986 · 10-04-2021, 06:07 AM

Deviations are measured at idle.

gabedrummin · 10-05-2021, 06:17 AM

Thats strange the auctuator dont move till about 2500 rpm . Jeff from Pa told me to check at 4500 rpm. At idle they are closed as the rpm increases the auctuators lift to adjust the timming .????

pilot4fn · 10-05-2021, 07:38 AM

Quote:

Originally Posted by gabedrummin

Thats strange the auctuator dont move till about 2500 rpm . Jeff from Pa told me to check at 4500 rpm. At idle they are closed as the rpm increases the auctuators lift to adjust the timming .????

Sounds like you're taking about Cam Actual Values here above.
Cam Deviation is diffrent item to check and should be checked at idle - at least for what I have read from all articles that I have seen...

blue62 · 10-05-2021, 08:00 AM

I don't think the average person understands what cam deviation values (as it apply to the Porsche Vario Cam system) represents.
What does the Camshaft Deviation value really represent???
Deviation of cams from factory set point in degrees of timing in relation to crankshaft position???
Deviation from factory set point in degrees of timing in the relationship of Exhaust cam timing to Intake cam timing??

OR????????

Secondly I don't think the Cam deviation values change with RPM unless there is an issue with the mechanic's.
The important thing is to have the engine fully warmed up when taking readings.

PLP · 10-05-2021, 05:13 PM

Actually, I would like to know what to exactly measure and how to measure.

I will be renting Durametric Pro again (to finally activate cruise control) and I could run all the checks.

It would be nice if someone took the time to explain this stuff and show which exactly screens/variables should be active/measured.

blue62 · 10-05-2021, 05:38 PM

Quote:

Originally Posted by PLP

Actually, I would like to know what to exactly measure and how to measure.

I will be renting Durametric Pro again (to finally activate cruise control) and I could run all the checks.

It would be nice if someone took the time to explain this stuff and show which exactly screens/variables should be active/measured.

As far as checking Camshaft Deviation it is simple:
Take the car for a good spirited 20-30 minute drive.
You want the engine oil good and warmed up and at a stable temp.
Hook up the Durametric and go to the actual values tab.
Click on... Camshaft deviation Bank-1
Click on Camshaft deviation Bank-2
Should bring up a graph and also number on the right hand side.
Do this at idle RPM.

Do a search here on the forum for camshaft deviation you will find plenty of screen shots.

If you have any problems figuring it out let me know.

Just noticed that you have a 2003 so I think your Vario Cam system is different. If it is the Vario Cam plus system then that system functions in a different way. So I do not know if Camshaft Deviation applys to that system. Perhaps someone here on the forum knows.

TTGator · 10-05-2021, 07:15 PM

Quote:

Originally Posted by blue62

As far as checking Camshaft Deviation it is simple:
Take the car for a good spirited 20-30 minute drive.
You want the engine oil good and warmed up and at a stable temp.
Hook up the Durametric and go to the actual values tab.
Click on... Camshaft deviation Bank-1
Click on Camshaft deviation Bank-2
Should bring up a graph and also number on the right hand side.
Do this at idle RPM.

Do a search here on the forum for camshaft deviation you will find plenty of screen shots.

If you have any problems figuring it out let me know.

Just noticed that you have a 2003 so I think your Vario Cam system is different. If it is the Vario Cam plus system then that system functions in a different way. So I do not know if Camshaft Deviation applys to that system. Perhaps someone here on the forum knows.

Or watch the video

Only inconsistency I see is I was told to do this from a cold engine and you are saying warm.

blue62 · 10-06-2021, 07:18 AM

Quote:

Originally Posted by TTGator

Or watch the video

Only inconsistency I see is I was told to do this from a cold engine and you are saying warm.

Yes well warmed or operating temp.
Very few tests of a system under operation are done (correctly) at other then operating temp.

........To many inconsistencies......

It is not only the temp of all the different types of metals involved.....bearings, valves, lifters, springs, cams, chains, sprockets, etc..etc..
Tolerances change with temp. (expansion, contraction).
But also and perhaps more importantly is oil operating temp. (around 175+ degrees F. I think).
These engines have a large oil capacity so it takes some time to get all that oil up to temp.
The Vario Cam system is operated by oil pressure as are the lifters, so you want that oil temp. (Thus oil pressure) to be as consistent and as close to operational specs. (pressure) as possible.

In "most cases" when doing any kind of operational or diagnostic testing on a system you want that system as close to manufactures specs. and operational conditions as possible.

Think about it... you don't operate the engine cold for anymore then the time it takes to warm it up. On say an hour long drive your at cold state for just a minute or two. The rest of the time temp. is increasing or has reached operating temp for the conditions.
Doesn't really make sense to test it cold.

Hope this makes sense.

Stl-986 · 10-06-2021, 08:02 PM

it should be from a warm engine. it doesn't hurt to do it from a cold engine. by warm some say take it for a 10 minute drive, some say just up to temp (10 minute drive in some places could just be 10' down the road)