Les Quam

www.rennteam.com has pictures of Tim Allens CGT which was towed in for an oil leak. Very interesting in regard to new car needing tow already?

GOBOGIE

Drewlin' over the pics.

graham_mitchell

here's the link:
http://www.rennteam.com/showflat.php...rev=#Post26697

ben in lj

Just got back from Leipzig and the CGT ride. They told me that the two examples in which we rode (7500 km on one and 3600 on the other) have done nothing but hard track duty and have had nothing but tires and pads replaced. Those two cars absolutely have the wheels driven off of them so if they are not mistaken with regard to their maintenance, it's very encouraging.

BTW, one person told me the valve adjustment for a non-track car only CGT should be in the 40k km range.

Les Quam

Ben,
I would not have expected Porsche to tell you anything negative about the car under those circumstances.

ben in lj

les, i wouldn't have either.

Mongo

valve adjustment? I thought that car has variocam? don't need to adjust hydraulic valves

As for Tim's oil leak, I'm sure Porsche will cover that under warranty. New cars even have tendencies to leak if there isn't enough gasket sealant on it.

Andy

adrial

The CGT has solid lifters; it needs valve adjustments.

FSAEracer03

Anyone else not able to load the photos??

Toby Pennycuff

Adrial,

Sorry, but I think you've been misinformed. If you read the technical specifications from the Porsche web site on the Carrera GT engine, you will see that VarioCam is a key component of the engine.......


From the
Carrera GT Technical Specifications

"Water-cooled, naturally-aspirated V10 with 68-degree angle and four valve heads; engine mid-mounted with longitudinal layout

Specific output: 105.5 hp (SAE) per liter

Dry-sump lubrication with nine-fold oil pickup for optimum performance under all load conditions

Titanium connecting rods for smoother and more immediate engine response

VarioCam® variable valve control on intake camshafts

Electronic engine management (2x Motronic ME7.1.1)

Aluminium twin-flow resonance intake manifold

On-board diagnostics for monitoring the emission control system

Stereo lambda control"

And I doubt seriously that Porsche would provide VarioCam one only one side (i.e. - the intake side).

Toby

W8MM

Why's Vario Cam mutually exclusive with solid lifters?

Can't it have both?

It does!

Toby Pennycuff

I will certainly defer to others who know more about the car. I assumed (of course, we all know the components of ***-u-me, correct?) that VarioCam and valve adjustments would be mutually exclusive. If they are not, please excuse my ignorance.

Toby

Toby Pennycuff

I went back and looked at my Cayenne Service Information Technik manual to understand a bit more about Variocam and its operation. It would appear that you are correct about the Carrera GT engine having solid lifters and Variocam. That said, the fact that the engine has solid lifters does not seem to imply a need for valve adjustments. While it's a rather elaborate summary, it appears that Variocam relies upon a "vane-type adjuster" to modify valve timing on the fly based upon DME calculations and engine operating parameters. Here's how Variocam is described for the Cayenne V8 - a cousin (distant though it may be), I suspect, of the Carrera GT V10. Please let me know if I misunderstood what the manual was attempting to convey. (Just a personal quest to understand how this stuff actually operates! )

"Camshaft Adjustment
"Camshaft adjustment at the intake camshaft is based on the operation of a vane-type adjuster. The DME determines the current position of the camshaft to the crankshaft (actual angle) from the engine speed sensor and Hall sensor signals. The position control in the DME determines the desired specified angle via the programmed map values (rpm, load, engine temperature). If there is a difference between the specified and actual angle, a regulator in the DME actuates a hydraulic solenoid valve according to the desired adjustment.

"Adjustment angle is 50 degrees crankshaft angle (25 degrees camshaft angle).

"Vane-Type Adjuster
"The vane-type adjuster consists of the stator (A) - attached to the crankshaft through a sprocket, and a rotor (B) - attached to the camshaft - the vanes and two covers. The sprocket is attached to the outer diameter of the stator. It is a positive fit to the crankshaft through the chain drive. The rotor is bolted to the camshaft. Rotation between rotor and stator is possible (inner mounting of the adjuster). This rotation is limited by the vames mounted in the rotor and the stops on the stator. The vanes also divide each of the recesses on tha stator into two chambers.

"These chambers can be filled with oil orifices and oil lines in the rotor. A cover attached to the sprocket seals the chambers. The adjuster is locked to a stop (retard). To do this, a spring-loaded pin in the retard position of the adjuster moves into a hole in the cover. A locked connection is created between the stator and rotor for starting the engine. This prevents noise during the time when the oil pump is starting to turn.

"Operation
"Two chambers acting in different directions are provided in the adjuster. Filling one chamber causes the rotor to rotate in one direction. By filling the other chamber, the rotor and camshaft can be rotated back to its initial position. The oil from the non-pressurized chamber flows to the hydraulic solenoid valve and back into the crankcase. If the oil feed and the oil return at the hydraulic solenoid valve is interrupted while one chamber is being filled (middle position of the valve), the adjuster stops in the position it has just reached. The chambers lose oil due to leakage so that the adjuster leaves its position. The hydraulic solenoid valve is actuated through the DME and the adjuster returns to its desired position again."

The diagrams that accompanied this description are attached below. The first depicts the camshaft/valve train setup....



And the second depicts the rotor/stator setup....




Boy, am I a sad case or what! Reading manuals on a Sunday night.

Toby

Les Quam

Toby,
I don't know about sad case. But this forum is a much better place because of you. Great post.
Oh and please stop showing off your computer skills. It makes us computer cavemen look, like well, cavemen.

Toby Pennycuff

Thanks for your kind words Les. Like I said, it's a pretty sad state of affairs when one is reduced to reading automotive technical manuals at 9:30 on a Sunday night! As for computer skills, I have to get some sort of return out of all the gear sitting in one corner of my office!

All the best,

Toby