Osmosis

I know this may be a simple question, but is the proper procedure to install the flex plate/fly wheel in the Bently manual for our cars?

I have never heard of a fly wheel being so specific in to how it goes on the crank. From looking at the pdf, it makes sence but Really.....does it have to be so complicated???

I hope the bently manual has the proper procedure with pictures.

Hell, if I have to do this procedure, I hope they write the instructions in crayons so I can read the darn thing

jcman

The Bentley manual claims to mark it before you replace it with really no more detail about aligning.
Knowing what position the sensor is looking for is not complicated at all, find #1 TDC "the compression stroke" and position the segment gap "open space" of the wheel to the sensor according to the pdf and bolt it down.

Osmosis

One question here,

The crank locking pin that is used while doing a timing chain stops the crank @ TDC for piston number 3, correct. If you pull the engine out, rebuild it and then set the timing belt, you then need to move the engine so the #1 cylinder is @ TDC compression stroke, correct?

the_duke

Once the timing is set why would it matter what position the engine is in?

Osmosis

I was thinking the same thing (once timing was set, it did not matter which cylinder was TDC), but with the flywheel needing that specific position with the CPS, TDC has no reference to which cylinder. To me, when I hear the engine need to be @ TDC, that says cylinder 1 unless otherwise specified. From everything I've read regarding the timing belt job, when the crankshaft pin locks in place, it puts the engine @ TDC @ cylinder no.3. To me, that is a little confusing from being a Chevy guy all my life. I'm Just trying to understand everything and yes, I don't see why it would matter once timing was set as long as the flywheel was put in the exact same position as it was removed. I"m Just trying to avoid any headaches since this project is very time intensive .

jcman

Two different topics here regarding the standpoint of what cylinder # TDC you want to know as the CPS looks for #1 and the locking pin centers #3. I see this thread was not a good source for your answer but I can understand some of the relevance.

aheinlein

It has been almost three years since I originally posted a question regarding the proper installation of the flex-plate on my 2000 Audi A6 2.7T. The engine has been installed and does run, but not well. I am getting error code P0346 (Camshaft Sensor G163 Implausible Signal). The symptoms are random misfiring of the ignition system on the driver's side cylinder bank that leads to fouled spark plugs in about 30 miles of driving. At this point, the car is not drivable. We have changed the engine wiring harness and cam sensor with no positive results.

I came across an article posted in Ross-Tech Wiki about the 2.7T flex-plate installation. Ross-Tech indicates that the flex-plate can be bolted up in several different positions. (Please see a copy of the Ross-Tech Wiki article) I have consulted with the local Audi dealer service department about the correct position of the flex-plate. Even the dealer has not been able to determine the proper mounting instructions for the flex-plate. I am somewhat convinced that the flex-plate is incorrectly installed leading to improper timing between the crankshaft position sensor and the driver's side cam sensor. Interestingly, the passenger's side cam sensor does not seem to be impacted. As such the passenger's side spark plugs do NOT foul out and seem to run normally. If I could determine the correct installation instructions for the flex-plate then my plan is to remove the crankshaft sensor and with the use of a borescope I could determine the position of the large gap in the flex-plate reluctor through the sensor hole. If I determine that the gap is misaligned then the transmission will need to be removed to correct the incorrect flex-plate alignment.

Once again, I would very much appreciate any assistance or instructions on the proper flex-plate installation for the 2.7T engine once the flex-plate has been removed from the engine. (Note: The Bentley manual says that the flex-plate should be marked prior to removal. I failed to do that. It would have been nice if VW had stamped a mark on the flex-plate!) Thanks for your comments and assistance.

georgeb944

I had the same problem when I did the clutch on my 2.7t 6MT. I neglected to mark the position before I disassembled it. Fortunately, I was able to use another 2.7T 6MT to figure out where to place the flywhel in relation to the mark on the harmonic balancer at the front of the engine. When that mark is in the TDC location (TDC on #3 cylinder), then the window (or missing teeth) is located at the hole where the flywheel sensor goes. Next time, if there is a next time, I will be sure to mark the position of the flywheel to the crankshaft before removing it...

aheinlein

Thank you so much for your kind reply! This is the first positive information that I have found on this subject. It seems like the factory is keeping the flex-plate alignment matter top secret and the local technicians don't seem to know about this.

If you have time, I am interested in whether you originally mounted your flex-plate in the incorrect position, installed the engine in your car and experienced similar symptoms. If so, it would be interesting to know whether you experienced the P0346 code, ignition misfiring and spark plug fouling. Obviously, it is a good deal of work to remove the engine/transmission assembly from the car to correct the flex-plate alignment. Before I start down the path of removing the engine/transmission assembly, it would be nice to track down any other potential causes of the ignition issues.

At this point, I plan to remove the crank sensor and use a borescope to determine the position of the crankshaft relative the "window" in the reluctor plate. If the "window" is not in the TDC position relative to cylinder 3 then it sounds likely that I have found the source of the problem. I have learned my lesson! I will be marking anything I remove that doesn't have obvious factory marks from this point forward! Thanks again for your kind reply.

georgeb944

Unfortunately, my A6 does not have a flex plate, in that it is a manual transmission car. It does have a dual mass flywheel, which has the same window as your flexplate. I did not mount the flywheel in the incorrect position, so have no insight as to what problems it might have caused had I done so. Good luck...