Cam Deviations
 

Hi all,
My 2002 Boxster 3.2s cam deviations are currently -9.86 on bank 1. Can't check bank 2 due to no sensor on uk cars.
I've not found any chain guide bits in filter or oil pan so was surprised that the deviations were high.
I'm struggling to find anyone to actually changed the guides without wanting to do engine rebuild or astronomical price. Whilst I know its a long job I can't warrant paying that sort of price on a £5k car.
The job is outside my skill range and I have no access to a lift.
So question is what are consequences of driving with the high deviations and is there anything else that can be done to help.
Car currently has 153k miles and drives like a dream with no knocks/ bangs/ smoke other than a slight chain rattle on cold start only.
Any advice welcome.
Thanks

You might watch my video on YouTube about this subject. Chain guides are a wear item that need to be replaced or eventually there will be big trouble.
https://www.youtube.com/watch?v=xXfR60GAJd0

Mine measured -6.9 on one side and I think -4 something on the other, and was throwing a code and idling rough. I also found a decent amount of plastic in the oil filter. I currently have the engine out, about to tuck into the replacement, among other things.

question - has it always been a -9 and you never had a problem, or you just decided to check and it was at -9, or did you get a cel which made you check? or perhaps engine started doing something it hadn't before which made you check?

i ask as my 3.2 with a row flash ran at -6 for years no problem, and only triggered a cel when it hit -9.

that says a few things ...

-9 it the limit for good behaviour set by porsche.
- that the car will run fine at less than -9.
- that the deviation was getting worse.

you see, the deviation is read by a sensor. if improperly set (either from the factory or by a mechanic after the fact) then the sensor can read off of true value. the real info you glean from the deviation sensor is not the absolute value but the change in value and the rate of that change over tiime.

for example, if it starts at -4 and stays there then suspect the sensor.
if it starts and one value and slowly decreases to a higher value (say it goes from -4 to -4.5 to -5 to -5.5, etc.) then suspect you chain pads are wearing and look for little brown plastic bits in your oil filter.
if it starts at one value then aggressively changes to say -16 then suspect your solenoids and look for little green rubber bits in your oil filter.

back to my initial question then - what is your deviation history?

At around 12 degrees off is approximately the same as the cam being off by one full tooth on the gear, which is a lot.

[Thanks for info.
No my car has not thrown any codes and runs fine.
I checked the Cam deviation just by chance as i seen it as a option on my new Foxwell NT530 .
I watch alot of info videos on the Boxster and one i watched was a guy who gave some maintenance tips if you ever had your engine out to give a longlivity to your engine and changing the Cam guides was one of the tips.
I have enquired about getting them changed at various Porsche Indies but none of them haver ever changed them for customers and basically said they were not interested in the job and they also said they have never seen a engine with cam guides failing ?
I do an awfullot of my own work on my car even down to a full Suspension refresh front and rear. But think this job is beyond my skill level especially as I do not have access to a lift.
This is why I asked what consequences would be to keep driving car. I will monitor it on a monthly basis just to see if it becomes worse.
I've not found any guide bits in filter as if yet or in oil pan.

QUOTE=The Radium King;656244]question - has it always been a -9 and you never had a problem, or you just decided to check and it was at -9, or did you get a cel which made you check? or perhaps engine started doing something it hadn't before which made you check?

i ask as my 3.2 with a row flash ran at -6 for years no problem, and only triggered a cel when it hit -9.

that says a few things ...

-9 it the limit for good behaviour set by porsche.
- that the car will run fine at less than -9.
- that the deviation was getting worse.

you see, the deviation is read by a sensor. if improperly set (either from the factory or by a mechanic after the fact) then the sensor can read off of true value. the real info you glean from the deviation sensor is not the absolute value but the change in value and the rate of that change over tiime.

for example, if it starts at -4 and stays there then suspect the sensor.
if it starts and one value and slowly decreases to a higher value (say it goes from -4 to -4.5 to -5 to -5.5, etc.) then suspect you chain pads are wearing and look for little brown plastic bits in your oil filter.
if it starts at one value then aggressively changes to say -16 then suspect your solenoids and look for little green rubber bits in your oil filter.

back to my initial question then - what is your deviation history?[/QUOTE]

well, i don't know anything about the foxwell unit, but you should have a code at -9 so perhaps you are reading the wrong value?

otherwise, while these are interference engines (ie, the piston can hit the valve if the timing gets way off) i've run my car at -16 without breaking it. it ran rough and i didn't do it for long (drive to the mechanic) however. if truly at -9 expect to be down on power.

me, i'd (a) confirm the reading, (b) confirm the sensor, (c) determine mechanism behind bad deviation (pads, failed/stuck solenoid, tensioners, etc.) (d) determine cost for repairs, (e) make the call to live with it or fix it. if fix it, realise that tensioner pad replacement is such a standard repair (albeit pricey) that porsche even updated the part for the tensioner pads as the originals failed on such a regular basis. so i'd find a new mechanic.

This was values
http://986forum.com/forums/uploads02...1695406363.jpg

Mine got worse the warmer the engine got, just as an FYI. You could see on the Durametric it went up over time (or down, I guess, as it is a negative number, technically!)

Cam deviation values should only be taken when the car is fully warmed up, like after a 20 min. drive................