3.2 V 2.7 Fly wheel
 

Does anyone know if a 3.2 Flywheel for a 6 Speed will work on a 5 speed trans. Original is 98611401201, 986-987 3.2 is 98611401206. My research is showing the primary difference is the internal damper springs are heavier in the 3.2, 6 speed flywheel

My LN 3.6 is eating flywheels. There have been to many negatives posted for running a ASSCO or similar LW un-dampened flywheel.

watching this with interest, as I am looking to put a 5-speed on my 3.2. my understanding is that the flywheel has to match the engine (different bolt patterns for different engines - ie, the 3.4 and 3.6 flywheels are not interchangeable). the tranny doesn't matter too much as all the input shafts are the same diameter and spline count.

To understand the differences ,you'd have to dissect some DMFs ?
Jake would have an interest in the answer your question?And he probably has lots of old DMFs -take-offs in his dumpster.
But here is a simpler idea. My brand new LUK dmf was not perfectly balanced! I had it balanced. O.K. only a few grams of metal removed from the periphery but not good !
I'll follow this with interest. Good Luck.

I purchased a very low mileage used DMFW 98611201406 from a wrecked 06 Boxster S (very low price). If I can't use it, so be it I wasted more money in a day at the track in gas. I'll get back to you.

It has to bolt to the crank. I've been running a 2.7 Flywheel on the 3.2 crank 2 years with no mods. The pilot bearings are the same part number in the Porsche parts listings, for all models Boxsters, all years up at least 2008. We'll see

How did you initially determine that it wasn't balanced?

Checking and adjusting balance on a DMF is a job for a skilled specialist -certainly not me !
John Edwards of Costa Mesa R&D did mine.
"The final issue is that if the clutch/DMF assembly wears and runs out of balance it can cause severe engine damage by overloading the crankshaft main bearings. This problem is especially prevalent on the 986, 987, 996 & 997 2.5, 2.7, 3.2, 3.4, 3.6 & 3.8 models, For these reasons Ninemeister highly recommend replacing the Porsche DMF at the same time as a clutch replacement and will only warranty a clutch package when fitted with a new DMF."
The whole story is here:
http://www.schaeffler.com/remotemedien/media/_shared_media/08_media_library/01_publications/schaeffler_2/symposia_1/downloads_11/4_dmfw_1.pdf
&
http://www.schaeffler.com/remotemedien/media/_shared_media/08_media_library/01_publications/automotiveaftermarket/poster_1/downloads_29/luk_dmf_poster_de_aus.pdf

I hope this helps

Well for the curious. I had the 2.7 5 spd flywheel and 3.2 6 spd Flywheel on the floor side by side. All the external measurements where the same. Mounted they set the same distance from the motors machined surface to the face of the flywheel. The Pressure plate aligns on the pins on the flywheel as do all the mounting bolts. I don't know how to measure the resistance in the dampening springs but the 3.2 springs are stiffer, there is more resistance.

Just to make sure I follow.
The two FW that you are competing are both new?

No drill marks from being dynamically balanced.

Correct -the machinist drilled out several shallow bores in the outer circumference - where it was heavy .
It was balanced with the pressure plate attached and marked accordingly.

To answer your question No. I have a brand new LUK 98611401201 (2.7L 5-SPD) OE Flywheel. I'm comparing that to a Lightly Used LUK 98611401206 (3.2 L 6-SPD) purchased from a dismantler. Less than 10K. The surface is just lightly polished enough that you can tell where the clutch disc road, the machine groves are still fully visible.

I've asked before what alternatives I had for my Base car with a 3.6 motor without going to a LWFW to have better C, PP, FW longevity. It looked like I could use a 98611401206 (3.2 L 6-SPD) DMFW, on the 5-SPD as a more suitable option base on the horsepower I output. I believe this is my next step base on the comparison. I have no doubt that it will fit at this point. No, I don't intend to put the used one in my car. Obviously it was more cost effective to buy a used one for a comparison, this way if it didn't fit I'm not discarding a new flywheel or giving it a way for 1/3 what I paid.

The engine should not be "eating flywheels". Was the flywheel replaced when the engine was built? Very few technicians understand the proper method of checking the flywheel for wear in the second mass, and few of those have the proper special tool from Luk to check it with properly.

The difference between 5 and 6 speed flywheels is enough to lock the drive train up when a 6 speed flywheel is used with a 5 speed tranny. That was one of the first bits of exchange that I learned with these cars. Its easier to use a 5 speed flywheel in a 6 speed trans, than the opposite, and the engine doesn't play a part in the exchange.

Finally, people have difference "balance tolerances". When I read that something has been "balanced" the first question I have is "to what tolerance"? The act of "balancing" can mean that someone removed one bit of material and the part was balanced. To me balance tolerance is .5 oz./in. measured at the largest OD of the mass. I trust no one to balance items, and thats why the same person that builds the engine from scratch, will also do the balance work. This is also why we balance the entire rotating assembly as it will be bolted together in the engine.

Thank you Jake for the definitive answer.
For the rest of us flailing fools ,here are the Luk info/instructions for the special tool from Schaeffler:
Schaeffler Automotive Aftermarket Germany | Services | Dual Mass Flywheel - Special Tool (DMF)
LuK United Kingdom | Services | Dual Mass Flywheel -Special Tool
And for the visual learners(like me)- this guy has an awful accent (Midlands U.K.)but is helpful:
https://www.youtube.com/watch?v=pgBxOOTKxMI
I labor the DMF issue because it can cause engine failure. A very sad day for you(& me)

My explanation of "Eating Flywheel" has nothing to do with balance. It has everything to do with exceeding the Free play angle. I am not getting surface deflection of vibration. I output a fraction over 290HP and 287 FT/PD torque at the rear wheels. When the springs start to degrade I can feel the excess angular deflection as the cam timing fully advances under hard acceleration and sometimes shifting. This is starting in as little as 12,000 miles, 1/3 of which are on track.

The plate that was just removed had about 25 degrees deflection from spring to spring clockwise to counter clockwise. There is another 15 degrees before the spring starts to feel solid in the drive direction. With six teeth in the internal plates, mechanical damage can occur at 60 Degrees. There isn't excess face deflection, and there isn't run out.

I too have struggled to find out the difference between the 2.7 and 3.2 flywheel. I just gave up trying to find the answer and ended up putting the 3.2's flywheel on my 2.7 crank. So far, no issues, weird vibrations, etc.

I also did put them on the floor side by side and measured everything, I could not find the difference between these two flywheels. I am guessing it HAS to be in the springs, that's the only thing I could not really check and compare (they both felt the same to me).

Sorry, not much help, just wanted to let you know that finding the difference between these two flywheels is no easy task. I'll be watching this thread in the hope that someone who knows for sure can answer.

'.Oops...forgot to mention. My car is a "s" with the six speed bolted to the 2.7 using the 3.2 flywheel, clutch, etc.

Piper

Thank you all. I talked to the local Porsche service technicians who said with my engine configuration they could not recommend using the stock 2.7- 5 Spd flywheel. He also could not make a recommendation on the 3.2 - 6 Spd unit. Bottom line I bought one installed it as well. Approaching 1000 miles 320 on track. I feels so much better than the stock flywheel when coming hard into acceleration. The feeling that something was shifting around at the point the torque band was reaching it peak was gone. I guess I was blaming motor mounts when it was just the springs in the flywheel giving up and collapsing.

I am not recommending anyone else does this unless you can afford a transmission. I also want to say I've researched the earlier half shafts and would not do this on a pre 2003 5 spd. 2003 and later the axle tubes are larger in diameter. The 2003 and later inner CV bearing have a 10.1MM through hole. This also allowed me to increase the bolt diameter from 8MM, by re-drilling and tapping larger threads in the transmission flanges.