Clutch just went! Should I fit a LWFW?

[Gibbo205]

Hi there

Well its probably long overdue on my car as since I've owned it I found it never seemed to light a fast start, such as revs at 3000rpm and dropping clutch, not much would happen, but as I rarely ever boot my cars from a standstill it did not bother me. Some 25,000 miles later and it seems like it has now had it, went for a change up from 2nd to 3rd at 7000rpm and the car just rev'd like I had missed the gear, but checked it was in gear, just clutch slipping like crazy.

Manage to limp it to my mates unit, so still drivable just about, so was not stranded, car is at 52,000 miles so I guess its not done bad on the original clutch.

I've priced up the parts:-
http://www.carparts4less.co.uk/cp4l/c/Porsche_911_...

£341.99 from eurocarparts for the sachs 3pc kit, am I right in that this is the same as what Porsche fit, as in its o.e. part?

I am also going to replace the slave cylinder at same time, so that is £100 too.


Some questions:-

I am told flywheel should be OK, but the modding bug has got me and I've read a lot of positive stuff on LWFW for the 997, has anyone here fitted a LWFW or no anyone who did? Any issues, did they like it and which is the best one to go for that will work with the original clutch kit?

Also will I need any fluid of any kind, brake fluid??

Me and my mate will have a go at fitting as it seems relatively simple and Mike at S&C said its not a bad job to do.

[fioran0]

Aasco flywheel is what you want. Definately worth doing. Is designed as a straight replacement so no clutch spec faffing.
I had one on the 4 liter 996 C2 engine I had. It's what the spec996 series cars use as did the 997 C2s running in grand am.

[Gibbo205]

fioran0 said:

Aasco flywheel is what you want. Definately worth doing. Is designed as a straight replacement so no clutch spec faffing.
I had one on the 4 liter 996 C2 engine I had. It's what the spec996 series cars use as did the 997 C2s running in grand am.

Hi m8

I've read that some people fear it can cause crank failure due to more harmonics/vibration and is why Porsche fitted Dual Mass on M96/M97. As my car is a road car I want reliability to be kept, is this something that would concern you?

If I did go with the Assco unit as I see it for sale, do I need to get it balanced or anything or just a case of remove old flywheel/clutch etc and replace with new?

I've ordered the sachs clutch kit from Carparts for less - £320 delivered with discount codes. :0
I've also ordered from Porsche a slave cylinder, release fork, ball pin for fork, spring clamp for fork, sealing ring, guide tube and bolts, so changing everything in there and leaving nothing to chance.

If I did go with this Aasco unit, do I need anything else, I've heard people mention a spring for the clutch or something to put less shock/load on transmission when setting off?

[NBTBRV8]

At 52,000 miles your flywheel would need replacing. See my thread: http://www.pistonheads.com/gassing/topic.asp?h=0&a...

[Gibbo205]

NBTBRV8 said:

At 52,000 miles your flywheel would need replacing. See my thread: http://www.pistonheads.com/gassing/topic.asp?h=0&a...

Porsche told me to check it first as the car has no juddering symptoms and it's not being exposed to and slipping. So I will keep my fingers crossed that it's ok.

If not then I need to decide if I go with stock dual mass item or go with a lightweight flywheel or not?

[NBTBRV8]

Well good luck and post back how you go.

[Gibbo205]

NBTBRV8 said:

Well good luck and post back how you go.

I will do, gonna attempt this with my mate this weekend fingers crossed, so shall be in his unit on axle stands. I know its gonna be fun, I changed the clutch on my Mustang some years ago on axle stands and I said never again, trying to bench press a 100kg gearbox and lineup results in a lot of blood, sweat and tears.

If it does need a flywheel I have two options:-

1. LWFW option from Aasco or SVP - A clear improvement in performance but there are some horror stores online, be really good to hear from anyone here who has fitted a LWFW, anyone?
2. Or go with Porsche genuine dual mass revised 2008 flywheel, which is about £700.


So both options are a similar price, one gives a performance advantage but there are stories that harmonics/vibrations can/could cause damage to the M96/M97 crank, whereas the stock dual mass item filters out a lot of these harmonics and as such is a safer alternative.

[dom9]

Gibbo205 said:

I will do, gonna attempt this with my mate this weekend fingers crossed, so shall be in his unit on axle stands. I know its gonna be fun, I changed the clutch on my Mustang some years ago on axle stands and I said never again, trying to bench press a 100kg gearbox and lineup results in a lot of blood, sweat and tears.

If it does need a flywheel I have two options:-

1. LWFW option from Aasco or SVP - A clear improvement in performance but there are some horror stores online, be really good to hear from anyone here who has fitted a LWFW, anyone?
2. Or go with Porsche genuine dual mass revised 2008 flywheel, which is about £700.


So both options are a similar price, one gives a performance advantage but there are stories that harmonics/vibrations can/could cause damage to the M96/M97 crank, whereas the stock dual mass item filters out a lot of these harmonics and as such is a safer alternative.

Might be worth contacting Steve at Vibration Free and asking about the 'Rattler' if you're concerned about the LWFW messing with the harmonics - have a Google.

I wouldn't be too concerned though, the LWFWs have been well tested in spec-type competition in the US.

[fioran0]

If you are hoping for some sort of response that gives you the all clear in terms of long term impact I suspect you will be waiting a long time.
Sharkwerks sells them and has done for a long time, Jake Raby says dont fit one, I had one fitted and saw no issue in the time I had the engine running (and it was both road and track), theres a post online with an exploded crank thats blaming LWFW........

You need to weigh up what you think the risk is and then whether its worth it. IMHO you shouldnt do it. Just fit the regular one and be happy. If it makes it easier, your engine is not going to suddenly start revving up like a GT3 engine with one fitted. Theres too much weight inside for that to ever happen.

[Gibbo205]

fioran0 said:

If you are hoping for some sort of response that gives you the all clear in terms of long term impact I suspect you will be waiting a long time.
Sharkwerks sells them and has done for a long time, Jake Raby says dont fit one, I had one fitted and saw no issue in the time I had the engine running (and it was both road and track), theres a post online with an exploded crank thats blaming LWFW........

You need to weigh up what you think the risk is and then whether its worth it. IMHO you shouldnt do it. Just fit the regular one and be happy. If it makes it easier, your engine is not going to suddenly start revving up like a GT3 engine with one fitted. Theres too much weight inside for that to ever happen.

Hi m8

I am with you on this, plus a 2008 revised Porsche o.e. one is probably best, plus if I come to sell the car, I suspect even though its a modded car most people would still rather the flywheel was not modified.

[jsb]

have you spoken to RPM, I believe they offer a LWFW as part of their CSR package.....Worth a discussion at least?

[Gibbo205]

jsb said:

have you spoken to RPM, I believe they offer a LWFW as part of their CSR package.....Worth a discussion at least?

The RPM option seems like an option, they have quoted me £350 which is pretty damn good, here is a picture they emailed me of it:-

[fioran0]

And how does that help with your concerns that your crank will break?
Are you now satisfied that a LWFW is for you?

[Gibbo205]

fioran0 said:

And how does that help with your concerns that your crank will break?
Are you now satisfied that a LWFW is for you?

The horror stories seems to be all started by the one same guy and RPM are using it, there car is now 2yr old and has had the press drive it very hard, no issues.

Seems as with the Internet one issue and it gets exploded out of proportion.

If it was your car would you fit one?

[ezywheels]

Hi Gibbo,

Did you get the clutch and FW changed OK yourself?

[RadiusTim]

RPM's CSR car has a dynamically balanced/blueprinted rebuilt engine with a lightened crank - they didn't just fit the LWFW while renewing the clutch.

Jake Raby/Flat6 Innovations website says that the only broken M96/7 cranks they've seen or heard about all had a LWFW fitted, hence they suspect there's a link. On the same page they say it's fine to fit a LWFW as part of a dynamically balanced M96/7engine build - as RPM did with their CSR.

Raby's underlying point seems to be not that LWFWs are bad, but that the M96/7 crankshaft is cheaply made from cast powdered metal, and so needs all the help it can get to minimise stress: help that a DMFW gives by absorbing harmonic vibrations, and lightening/blueprinting would give by reducing it at source.

[Gibbo205]

Hi there

My mate got the box off all OK, he said it was pretty straight forward, the slave cylinder was a bit of an arse but it came, bear in mind this is being done on axle stands.

The flywheel seems OK, its only moving 1cm to either side and springing back to centre. RMS is leaking though, so we've delayed putting new clutch in and am ordering all new bolts, rms seal and the special tools to install it.

Some images of my flywheel:-






You can see its wet behind the flywheel, so RMS needs doing, ordering parts from Porsche.

Flywheel does have some hot spots, but its moving left to right within Porsche spec and is returning to centre. Emailed the photos to Porsche for them to comment on the hot spots.

If they say its OK shall get some emery paper and rub the flywheel down, replace RMS seal and then all shall be back in and installed. Literally changing every component whilst this is out, so slave cylinder, any bolts we undo new are being installed, all seals, guides, gearbox oil all new/fresh going back in and genuine parts.

[thegoose]

I think the usual wisdom is to replace the intermediate shaft end housing/cap thingummyjig too whilst you're in there.

Is there a solvent type solution that can remove the friction material deposits without having to rub down the flywheel?

[Gibbo205]

thegoose said:

I think the usual wisdom is to replace the intermediate shaft end housing/cap thingummyjig too whilst you're in there.

Is there a solvent type solution that can remove the friction material deposits without having to rub down the flywheel?

Porsche reply was along the lines of replace the intermediate shaft end housing/cap like you say and that flywheel looks and sounds fine. Take some sandpaper to it and rub it down to roughen it up and all will be good.

[Gibbo205]

Flywheel off, RMS is dry, its all coming from the IMS. So IMS seal kit shall be ordered.