Macster

The rings are steel but only alum. showed up. But that could be due to the brief (?) time the OP let the engine run before shutting it off.

I agree. This will be interesting to see what's going on.

I hope for the OP's sake nothing serious, but given the symptoms....

Sincerely,

Macster.

Kevin

Macster there is no sleeve of bushing. The rings fit into a cap secured firmly with three allen fasteners, they are even loctite'd from the factory. The camshaft has aluminum caps securing the four camshafts to the camhousing. The aluminum is most likely coming from the rings that are coming apart and wiping out the aluminum cap.

Kevin

FYI, this previous thread has most of the information behind this failure.

https://rennlist.com/forums/996-turb...ode-p1325.html

haulinkraut

Normally I am not a lawsuit kind of guy. But when people in the dozens are driving 911 turbos with engines making metal, the word "class action lawsuit" comes to mind. This is just ridiculous. Audi had this happen with the Dynamic Stability Control issues on the RS6s and RS4s when it became a common issue and Audi ended up having to replace DSC pumps on 5+ year old cars. That was not a 20k part either! Asking Porsche nicely will never get this resolved.

Macster

That's the way I heard it. I may have heard it wrong. I'll see if I can swing by there tomorrow and get more info/detail. Besides I'm anxious to know the reason the engine's out of the car, why the engine's sick.

Sincerely,

Macster.

Kevin

The part that is in question is circled Part number 7.. The camshaft lays inside the camhousing which is shown. Again there is no bushing or sleeve in the cam housing that will wear. However, number 7 is made out of aluminum and has shown to get wiped out with the failure of the sealing ring.

Haulinkraut you have a point. The stats point to 1 in XXXX of this happening to you. However, the owners pool on Rennlist is screwing with the numbers..

I do feel that the root of this is a oiling issue, the reduction of metal conditioners across the board.

PAULUNM

Speaking of oiling issues- I would LOVE to see an oil analysis of the OP's current oil...

akfalar

Just pulled oil and there were no detectable (visual) solids in it. I was near 4,000 miles on a mobile 1 5-40W diesel formulation.

On to pulling the #6 spark plug to investigate the misfire issue noted on the CEL.

Macster

Well, I stopped in again this AM and got a bit more detail on what I was referring to. There is a metal sleeve pressed onto the nose of the intake cam that has oil holes the match up with the oil holes in the cam's nose and these (I was told) ultimately feed the oil to the actuator on the nose of the intake cam.

This sleeve is a press fit but under some conditions the sleeve can loosen and twist a bit and if it does it can block oil flow to the actuator.

Why the sleeve is there I have no idea. The failure is rare though.

Sincerely,

Macster.

Kevin

I wouldn't use the phrase "pressed on" As techs we don't walk over to the 20 ton hydraulic press and fit the components. Part number 7 "housing" fits over the three oil control sealing rings > on the intake camshaft. The housing is bolted to the camshaft housing. It does have two oil supply holes. It also supplies oil to the Vario-cam module> which is designed to advance the camshaft.

If PorscheDoc sees this I would ask him to check the alignment of the "housing" I wonder if Porsche has missed a oil passage in the cam-housing by mistake (did not drill it).

Macster, if you can print out the screenshot and ask the tech>> number 7 is the part in which I believe is the problem. Can you ask him if there is any "internal memo" that is circulating prior to this getting more formal.

Macster

As an ex-machinist I'm well aware there are various classes of press fits. Not every press fit requires a huge press. I've done many using a small non-powered mechanical press, or even a milling machine vise or even a bench vise. In fact often one can cool one part (actetone and dry ice) and the warm the sleeve (the oven if the missus ain't around) and just drop the sleeve down over the end of the shaft.

Anyhow, the tech indicated the the #7 part was not the problem in the case of the engine I was referring to. The tech told me it was the 'actuator' which I believe is that cylinder like object that hangs off the front front the intake camshaft.

I have a pic of a camshaft -- took it today -- but it is not the kind that has this sleeve on it. But I was told the Turbo's camshaft is similar.

Here is the pic:



But I will do as you ask and report back.

Sincerely,

Macster.

Kevin

By chance is the dealer that you frequent Sonnen?

The parts that you have pictures aren't close to the 996TT components in question.

The intake vario-cam "actuator" module bolts to the intake cam.

joelesmith

That looks like an intake cam from a 3.4 carrera.

joelesmith

from 996 carrera PET

Macster

Not Sonnen. I've never been there.

I know the cam I photographed is not a Turbo cam but I snapped it just to have something for my pics files and a tech (not the one working on the Turbo engine) indicated there were some common characteristics. But I need to see the real Turbo cam to know what if any apply in this discussion.

Now, I have a factory Turbo manual and it does not show the detail the tech was referring to, the sleeve on the end of the Turbo's intake camshaft which is one reason I went in today to try to get some more detail/info.

Anyhow, the drawing I have shows the cam behind the 'oil guide housing' (item #17 in my docs) but the two items #7 in your drawing and #17 in my drawing look identical.

Also, it looks like (and based on what I saw of the engine and I posted a pic of this in an earlier post) item #15 (actuating element for inlet camshaft) bolts to the nose of the cam.

Anyhow, I'm going by the dealer again tomorrow and hope to have more detail before I make a nuisance of myself. They treat me pretty good, let me ask questions, but I have to be careful I don't wear out my welcome.

Sincerely,

Macster.