Aasco flywheel is here.

[JAAY]

If you watched my 3.4 start up video, there was a rattle from the rear. My Dual mass flywheel was shot, once again. So I bought a light weight flywheel from aasco. The thing is sweet looking. I may have it in tomorrow. I already pulled my tranny and yanked out the clutch and flywheel. Well enjoy the pics.





Notice the sweet pilot bearing. Nothing like the factory one.


I like this one!

[Jake Raby]

Look for a multi-faceted article on this topic on my site in just a few days, with data, with pictures.

[JAAY]

What is this going to be about? I tossed my first flywheel with about 35k on it. My second one, also porsche oem part. Lasted about 4k miles. It shifts a good 3/4 of a inch in both directions. It rattled like a mofo at idle. I'm just done with a dumb problem like that. I have driven many puck clutch lwfw cars and the chatter and how to drive it is not an issue for me. Give me some insight on your article please

[Bladecutter]

Originally Posted by JAAY

What is this going to be about? Give me some insight on your article please

I'm going to guess that its in regards to the light flywheels breaking Porsche crankshafts, because they no longer keep the crankshaft in balance, and it eventually shakes the crankshaft in half.

BC.

[JAAY]

I would love that. JK They seem to work great on peoples track cars. I had light weight flywheels on 3 other cars and never had such a issue. One of the cars had over 90k on that setup.

[Bladecutter]

Originally Posted by JAAY

I would love that. JK They seem to work great on peoples track cars. I had light weight flywheels on 3 other cars and never had such a issue. One of the cars had over 90k on that setup.

It depends on the engine manufacturer.
Some companies fully balance the crankshaft, and the only thing that the flywheel does is provide needed inertia.

Other companies rely on the flywheel to provide the balancing forces for the crankshaft, along with the needed inertia to keep things spinning.

I could almost guarantee that your other engines were all internally balanced crankshafts, and that's why you didn't have any issues using a lighter flywheel.

Maybe your company took the balancing needs of the Porsche engine into consideration.
I don't know, so we will have to wait and see what Jake has to offer.

But yes, its kind of need having an actual sealed bearing as the pilot bearing.
Still doesn't make it much easier to replace if it goes bad, though.

BC.

[JAAY]

ok. I see where this may go. I just read an article that Jake posted back in 08. The article was about a track car with 12k track miles. That is a lot of miles for any car on a track. In my opinion. I know nothing about how often track cars are rebuilt or whatnot. I hope your article is going to be good news for me not keep buying junk porsche flywheels.

[Jake Raby]

You clearly know far more about motors than I ever will, but do you really need to repeat multiple times that anyone putting in a solid FW is brainless or an idiot?

I never said or implied that!

What I did say was people wouldn't make these decisions if they sat down and actually used their brains before making decisions..(to use a brain you must have one, right??!!)

You assume the risks and you understand them, but you are one of the few that has done this. If it fails you pick up the pieces and go on, thats what I do. If what I learn and share saves one engine in the hands of the normal Porsche driver it is worth it to me.

I see lots of people choose components for these engines for the wrong reasons.. Things like exhaust systems that sound better, but cost efficiency and MPG along with net performance is just one of the dozens of things people do thoughtlessly on a daily basis.

I have strong feelings concerning components and feel that nothing should be added to an engine or vehicle that doesn't increase it's performance in some way, without c reating a compromise.. Performance isn't sound or looks to me, but thats just me.

Sorry if anyone felt I called them brainless.. I never meant to, I just want to stimulate thought so people can put those brains to work that they do have.

[Jackelfox]

I'll be first to admit that even if i sat down and thought about light weight flywheels all week i would be no closer to making a better decision much less a "good" one.

I have a brain but it doesn't have the relevant and necessary motor-knowledge to reason through auto performance decisions like this or most (any) others.

I very much respect and appreciate the amount of time/knowledge that you put into these engines Jake. I hope to be able afford buying myself the benefits of that knowledge in the not too distant future. That said, in the mean time please be patient with us commoners.

[Jake Raby]

Originally Posted by Jackelfox

I'll be first to admit that even if i sat down and thought about light weight flywheels all week i would be no closer to making a better decision much less a "good" one.

I have a brain but it doesn't have the relevant and necessary motor-knowledge to reason through auto performance decisions like this or most (any) others.

I very much respect and appreciate the amount of time/knowledge that you put into these engines Jake. I hope to be able afford buying myself the benefits of that knowledge in the not too distant future. That said, in the mean time please be patient with us commoners.

No worries..
This is the reason why I am working hard on the tech articles on my site and putting them in laymans terms as mush as possible..

[edevlin]

I have the Aasco LWFW with a sprung clutch. Acceleration and responsiveness is great, shifting is butter smooth. I absolutely love it other than the rattling noise in neutral."

I thought others have reported that a Spec or other sprung clutch with LWF got rid of the rattling noise when the car is in neutral and the clutch is out. Mine does the rattling thing in neutral when the clutch is out, but I thought that was because I was using a stock clutch.

Ed

[Jake Raby]

Installing this flywheel removes ALL harmonic dampening of your engine and transaxle..

One person has recently broken a crank... He didn't listen to me when I told him what caused his issue more than likely, so he reinstalled the same flywheel on his new crate engine. Two events later I got another phone call from him stating that he had broken another crankshaft and he should have listened to me. He is now on engine #3 and is broke, so broke that he is having to make one engine from 3 broken cores..

Another engine (2.7 DE car) had a knock, it was pulled apart and had a cracked and breaking crank.. When I threw the assembly for this engine onto the balancer it was immediately 10 grams out of balance, when the pressure plate was added that went to 19 grams and the flywheel was nearly new and had never been touched..

Both of these are in addition to the X51 engine that snapped a crank in half last year, also using a LWFW... There have been two other instances of similar consequence that people have contacted me about since the new year, but I did not see their parts first hand.

Harmonics have to go somewhere... The dual mass was utilized for a reason-Components that are forced to absorb them won't like it.. And it appears that these harmonics also end up being sensed by the knock sensors as possible detonation, so then the ECU retards timing and that reduces HP. I have gathered data that proves that these harmonics that can't be absorbed are directly related to reductions in net power, as much as 5HP in one instance from my test car.

I don't mean to burst your bubble, because you'll probably never have an issue, but it is my obligation to share my experience with the direct development of these engines.. If nothing else I like to stimulate the readers thoughts, because then the common sense might start to kick in....

We are working on a harmonic dampener for the M96 that should help with these issues, but it is not completed as of yet.. Porsche utilized this damper on the 997 engines, so they must have had some reasoning for this....

EVERY broken crank I have seen was broken when coupled to a LWFW, 4 of 5 of them were track cars and 1/5 had never hit the track and it was the worst failure of all..

You may also want to consider that the stock flywheel isn't junk but is just doing it's job... Something is causing the flywheels to fail as it is the job of the dual mass to ABSORB the harmonics and that damages the flywheel's second mass...

Just think about that.. This is the kind of stuff I think about 24/7-

I have whittled flywheels on all sorts of other engines to virtually nothing with no adverse effects, these were not the M96 and these previous experiences of mine, and yours mean nothing.. I have an aircooled Porsche engine that revs 9K that has a 2 pound flywheel installed, the stock flywheel for that engine weighed 16 pounds.. But it isn't an M96 and was not an externally dampened engine..


Thats all I am willing to say prior to my article which is guaranteed to start a flame war, mostly with those that have never touched the internals of an M96, a balance machine and probably don't have a tool box- but they are experts.

[23109VC]

maybe I am reading this thread incorrectly... BUT it sounds like Jake is saying our engines are balanced from the factory.

if you do a clutch job, I am under the impression that in many cases the stock flywheel needs to be replaced due to wear.

so it comes off and a new one goes on.

Assuming you put on a LWFW, I can understand how you throw things out of balance, as it is a lighter part.

if, however, I put on a new OEM flywheel - even though it's a stock part - because everyhting has been taken apart and put back together - will it STILL be "out of balance" and potentially fail - just like it would with a LWFW???

if that is the case - then anyone who does a clutch job and changes out the flywheel now is on the verge of a crank failure??

i'm confused...

[Jake Raby]

First off, prevuious 911 engines had forged steel cranks, not cranks made of sintered material... I have only seen one 911 crank, two 914 cranks and two 356 cranks break in all my days with aircooled Porsches. NOTHING with this engine and the prior 911 or other Porsche engines is the same. The vintage Porsche engine was not designed to have a dual mass arrangement and the design is what is creating some of these issues coupled to the cheap ass materials used in modern engines.

The cranks in early engines were extremely strong and wll over built for the application, never confuse anything that the Porsche engine of yesterday and the Porsche engine of today may have in common. The only thing they have in common is being 6 cylinders and horizontally opposed-

Aasoco and other providers do not build engines and until our program came along not many people had ever torn into or rebuilt these engines. When a crank would break people would just discount it as an extreme case and would never even consider the flywheel as a source, until it happened twice to the same person.

Lots of components are manufactured without the manufacturer having direct interaction with the entire engine as a primary objective, so they may never see the things that their component actually does..

[JAAY]

So I sent my aasco flywheel to Jake Raby in exchange for a stocker. It will be interesting to see what he does to the aasco. Maybe well see a harmonic balancer in a crank pulley or something cool like that?

[Jake Raby]

Originally Posted by JAAY

So I sent my aasco flywheel to Jake Raby in exchange for a stocker. It will be interesting to see what he does to the aasco. Maybe well see a harmonic balancer in a crank pulley or something cool like that?

I'll be using that flywheel to attempt to collect data on engine harmonics with both a stock and LWFW in iterrations per second via a couple of new sensors that I have located that give analog inputs into my data acquisition system.

I may soon be able to see exactly what the engine feels and graph the differences for overlay comparatives. This could make my article very interesting.

[Jake Raby]

Balance and harmonics are two different things... Sure an engine thats out of balance will have more harmonics, but even an engine thats perfectly balanced will still have harmonics that need to be absorbed..

The dual mass flywheel and it's dampening characteristics help to absorb these harmonics, the LWFW does not have any dampening capability because it has no second mass separated from the primary mass by absorption material.

Consider the fact that the dual mass flywheels that do fail may be failing because they are actually doing their job!! A flywheel is a wear item, it is a component that is designed to be disposed of after it's job is complete... A crankshaft is not a disposable item and if not absorbed somehow, somewhere these harmonics will find the weakest link and thats when things break.

With the M96 everything is rigid once the dual mass is removed, that means the harmonics from the engine, transaxle, CV joints and even the axle bearings are all going upstream directly to the crankshaft.

When the mass of a dynamic assembly changes as radically as it does when a LWFW replaces a DMFW the plane of balance must be compensated for, that means even if the flywheel that is placed onto the engine is perfectly balanced, when coupled to the rest of the dynamic assembly it will be imbalanced if the plane is not corrected.

The only way to do this is with the engine disassembled in a balance machine like mine. Thats why I refuse to install a LWFW onto any engine unless I am creating it's engine from scratch and can ensure the unit is balanced as a complete dynamic assembly then indexed for reassembly.

FWIW I have yet to see a single LWFW that has ANY balance marks on it brand new out of the box. Every unit I have spun up has had imbalance that exceeds my tolerance threshold...

When the second mass is removed where do those harmonics go?????

[edevlin]

Interesting stuff, I sure like learning more about our engines. In my case I have almost 3 years and 40K on my Aasco lightweight flywheel, and I love the driving experience with it, engine and car are much more responsive.

I did not think much of it at the time, but right after it was installed, it did seem to me that there was a bit more vibration comming from the engine compared to the factory flywheel, another subjective data point for the discussion.

As I said, I really like the performance of the car with the lightweight flywheel, but I must say, if I had known back then what I know now about the harmonic balancing function of the flywheel, I pretty sure I would have kept the unit stock, live and learn.....


:dance:

[JAAY]

Calling my Porsche buddy to see how much a stocker is. But. Why did my other go within 4k miles?

[Jake Raby]

Ummn, what do you think the components feel if they are screaming that way just at idle?