Flywheel Differences

[Duezzer]

Hi There,

Looking to find out the difference in these 2 flywheels.

986-114-012-05-M37 (for a 99 Boxster)

And

986-114-012-06-M37 (for a 2001 Boxster S)

Is it possible to install the 986-114-012-06-M37 into a 99 boxster?

Will it bolt up to the crank?
Will the 5 speed transmission still be mountable?

If anyone has drawings or pictures or a good discription of the difference I would appreciate if they could post them


Thanks

[Duezzer]

Guess I should of stated that I am still hunting down the no idle issue - Took it to a most recommend shop here in Calgary and after 5 hrs of diagnosis their thought is the fly wheel either has bent teeth, improperly made or is the wrong flywheel. The came to this diagnosis after checking the output of the Crank Position Sensor - They checked to see if it was a bad sensor - it was not - they modified an old sensor to go closer to the teeth on the flywheel and the car fired up but timing is out and car is not drive-able - Loaded up the car brought it home and have just finished pulling everything out of the way to drop the trany on Wed night and take a look at the flywheel.

My question is - if they sent me the incorrect flywheel would it actually fit?

Thanks

[BYprodriver]

I believe any M96 flywheel will bolt to any M96 crankshaft, & I believe the ring gear with reloctor wheel, is interchangeable among any M96 dual-mass flywheel. I believe this because I don't know any reason they wouldn't be, given Porsche's goal of making as many parts as possible interchangable for all their vehicles. Jake Raby recently hinted that the flywheels are not interchangable for different engine sizes, due to different dampening requirements.
So I don't think you have solved your problem unless you have a bent "tooth"

[Gelbster]

Now for some WAG before the evidence is offered:
Would a badly worn (= wobble & or excessive rotational free-play) DMF cause the idle problem? If the car has over 70k miles(??) ,the DMF is due for very careful inspection & probably imminent replacement anyway.
DMF wear may explain why the Crankshaft Position Sensor is giving fluctuating readings ?

[Reebuck1]

I do not believe the 98 or 99 five speed transmission will allow a Boxster S DMFW
to fit or run properly in the smaller transmission housing. I AM NOT 100% CERTAIN THOUGH. The reason I say this is when I installed my 996 3.4 motor in my 98 Boxster I was unable to get the DMFW from the 996 to fit in my five speed
housing and I had to go to a Boxster S six speed to get everything to work. I do think it might fit in a 987 five speed housing.

[Duezzer]

The shop I took it to said their diagnosis is that the new flywheel I installed has an issue and that is why the readings are not correct from the Crank Position Sensor - They wanted another 7 hrs to pull it apart and inspect. I am having a tough time with their diagnosis so decided to bring the car home and do the inspection myself. I understand how they got there. They were recieving week reading from the sensor and when they modified it so it sat closer to the teeth they got a better signal, car started idling but timing is out of whack and was not drive-able.

There is a new (possibly damaged, not made correctly or incorrect) DMFW in the car.

[Smallblock454]

Question: what are the exact symptoms that make the car undrivable? Is it only the sensor values, or are there vibrations, or noises, or anything else? Maybe i've overseen something.

As you might know there are a lot of things that can be done wrong when installing a clutch system. Did you triple check everything when installing? Are you shure everthing is 100% centered?

Did you check the flywheel befor installation and compare it with old one? Did you check the clearance angle (Freilaufwinkel) of the old and new one (that's a must).

There also some things you should never do to a new dual flywheel: https://static.profiteile.de/tmedia/org/006/415_417_SE_VERB_EN.PDF

Some additional infos on dual mass flywheels. Also what symptoms DMF can cause: https://static.profiteile.de/tmedia/org/006/415_417_600_BR_VERB_EN.PDF

The clutch diameter of all clutches are the same: 240 mm.

The 2.5 and 2.7 do have other dual mass flywheels than the 3.2 engines.

I'm not shure if you can install a 3.2 DMF on a 2.5 engine, because i never tried to.

[Duezzer]

So this saga started last fall - fired up car and it ran very rough - Thought I had an IMS issue - The death rattle.

Took car to buddies shop - We pulled the transmission to get to the IMS - noticed clutch and flywheel needed to be replaced - Ordered all 3 plus AOS and a new set of plugs and a RMS

Installed all above - went to fire up - would not start - flooded itself so we thought.

Cleaned up plugs - fired up and we let it idle for about 30 min - just to do checks make sure there was no leaks.

Went to pull out of garage and it would stall as soon as load was added to engine . If you kept the RPM above 800 or so it ran beautiful. Smooth no popping not hesitation. Took it for a road test - no codes no issues as long as the car's rpm were kept above 800.

While idleing in driveway CEL came on.

Checked codes - first one was CPS - Changed it out - no help

On the next start CEL came in again.

Was ICV code - Changed it out - no help

Took to shop - They state there is something wrong with flywheel - either flywheel issue it self or install issue.

Now pulling it apart to check to see what is wrong.

I have the old flywheel and will be checking for installation issue and flywheel issue.

[Smallblock454]

So the problem was there before you changed the clutch and the dual mass flywheel.

I would start from there.

How did that rattle sound? Like something loose? High sound, deep sound?

Bad idling and stalling - some ideas:
Did you check if the engne gets false air?
Did you do a pressure test? I don't mean compression, i mean if the system looses underpressure.
Did you check the MAF? Is it clean? Does the throttle valve closeses 100%? So no gaps, or bearing play?
Did you check the timing - especially of the camshafts? Because if a chain is jumped over you'll have a bad timing, which can cause a bad idling, but also a good runiing engine at higher rpms. But in the end you'll get a bad engine fail.
Did you check ignition coils?
Did you check the O2 sensors?

[jimk04]

I have read that the 996 3.4 FW is 5 or 6mm thicker than a 3.2S version..

[woodsman]

Wow, bummer you have to pull it after all that work. Really makes me wonder what that rattling was. My bet is the timing's off- did anyone check it? BTW my car ran perfect with the CPS just about to fall out because a mechanic forgot to retighten the bolt.

[Duezzer]

I am waiting for a call back for the shop I took it to to go threw all the diagnosis they did. - I am suspecting they checked the timing as they charged me to replace the caps on the timing inspection ports (lock points when doing the IMS) but want to confirm.

I am not 100% that the initial rough idle and noise - that happened last fall is the same as it is doing now - the rattle I suspect was the old worn out DMFW clanking.

Engine Coils boots and plugs all replaced.
Changed out MAF, IVC, CPS, AOS
No Codes on O2 Sensors
Cleaned and checked Throttle body - in good shape
Checked for vacuum leaks - none
Checked the fuel pressure regulator (shop did) all good according to them.

What is False Air? - never heard that term

Pulled everything off the other night but the transmission - Pulling it tomorrow to take a look at the Flywheel.

Thanks for the tips, thoughts, encouragement and sympathy

[Duezzer]

SmallBlock454 - the car has no power - will fire up but if you try to drive it just powers out now - this is only since they modified the CPS to fit closer to the teeth to get it to start.

Will sit and idle nice now but wont run nice like it did before above 800 RPM.

They stated the CPS was not giving a strong reading on their scope. They tried a different one they know was good and same issue - once modified to be closer to the teeth on the flywheel they got the car to start and idle but still getting an odd signal from the CPS - Stronger but somewhat erratic - Thus their belief that the there is a problem with the flywheel I installed.

I made a mistake of not checking the flywheel over carefully - had them side by side and looked really similar - but did not do a - are the teeth the same - is the gaps in the same place - is the locking pin in the same place kind of check - kicking my butt for not doing this - Still have the old one so I will be doing a thurough inspection of the 2 tomorrow night

[Smallblock454]

Man, wrote a long text, got logged out. Now its gone.

Short version:

Well, i think i've got you wrong. Problem is above 800 rpm; thought it is below 800 rpm.

Flywheel generates an alternating voltage signal by each teeth of the flywheel (magnetic field). Also it generates a peak every 360 degrees. Don't put the CPS sensor closer to the flywheel, because this will cause a different alternating voltage and wobbling. So maybe a wrong flywheel - wrong amount of teeth.

I think that if the flywheel would not be installed in correct positon, the engine would not run, because Crank Shaft Position and Camshaft Position Sensor work together.

Just an idea:

If the engine runs at idle and has problems to rev up i think there are 2 factors.

The ECU didn't get a signal to turn the ignition to "early" -> Sensor problem; wrong signal
There is not enough fuel -> fuel pressure test

Did you check if the trottle body you replaced is the correct one?
Did you check if the potentiometer sends the correct voltage signal to the ECU?
Did you check if there is a correct voltage signal running from the potentiometer to the ECU?
Did you check how the sparks look like? Maybe wet?

Does the ECU throw error codes?

Wrong air: german term is "Falschluft". I'm sorry that i don't have a better translation. It means that the underpressure in the engine is troubled by a leak. Air can get in there. We call it "wrong air". Maybe someone can give me the right english term.

Thanks and regards Markus

[Duezzer]

Pre going to the shop for diagnosis the car would not idle. Might last 10 sec at 200 rpm. every once in a while it would catch and fire right up. If you kept the throttle just off idle it would run like a dream. Actually took it for a quick spin. If you took your foot off the gas it would start to chug and shut down. Now after going to the shop it does idle after they made the CPS sit closer to the teeth on the flywheel but car has no power and backfires slightly. They claim all evidence currently points to a bad flywheel

[Duezzer]

I called this shop today. To find out all that was checked to make the diagnosis. They were not very forward coming with the information. 5 hrs do diagnostic time and can't get what they did besides, finding a poor signal from the CPS but the sensor gives a good value when activated properly. They stated the checked the fuel regulator and fuel pressure was fine. Asked if they checked the timing as I was charged for new caps on the cam locks. He said yes but without it running properly could not say the timing was off. This confuses me.
I only cleaned and inspected the throttle body. It was clean and in good condition. Car only has 120,000 km on it

[Smallblock454]

Do you have an invoice for the dual mass flywheel? Does it say which brand the DMF is? Or do you have a the packaging, maybe there is a sticker with the manufacturer and some additional infos on it. Or maybe you'll got an install instruction with it. Normally a DMF doesn't come without packaging and installation instructions.

For example if it is a LUK DMF the right DMF would be a 415 0072 10, whereas the wrong would be a 415 0120 10

Did you buy it from a Porsche dealer, or after market?

Do you have access to a OBD2 diagnosis, or a Durametric diagnosis? I would be interested in up to date error codes.

[Duezzer]

The DMFW is a LUK but the packaging is missing. Bought it thru 986Online. Have an OB reader and before I drop the transmission tonight I will take readings. Do not have a durametric. Thanks for the #s will see if I can find some paperwork. Is the # on the flywheel also? Guess I am going to find out.

[Smallblock454]

Couldn't find out if the LUK number is stamped on the LUK DMF.

These are the infos i got:
LUK 415 0072 10 (G86.00 5 speed transmission - Boxster 2.5)
Porsche OEM 986 114 012 01, 986 114 012 02, 986 114 012 05
EAN: 4005108012746
Max. clearance angle (Freiwinkel): 15 degrees
Amount of teeth max. clearance angle (Freiwinkel): 6 teeth
max. tilting free play (Kippspiel): 1.6 mm

LUK 415 0120 10 (Boxster 3.2)
Porsche OEM 986 114 012 04, 986 114 012 06
EAN: 4005108178145
Max. clearance angle (Freiwinkel): 14 degrees
Amount of teeth max. clearance angle (Freiwinkel): 5 teeth
max. tilting free play (Kippspiel): 1.6 mm

So if you don't find a number on the DMF, you can still check if it is right by checking the max. clearance angle.

Regards from germany
Markus

[Duezzer]

Hi There,

Pulled the flywheel, was the correct flywheel.

Found 3 bent teeth (2-3mm) on the side with the gap and 4 bent .5mm on the opposite side.

Made the mistake of not double checking parts. Very sure this happened during shipping.

Only did a quick look when I pulled it out of the box to make sure it looked like the old one - it did and put it in - did not notice the bent teeth.

New flywheel required.

Thanks From

Your Canadian Pal

Glenn