Lightweight flywheel & shift pins - w/ Feedback + Video

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pingu
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Lightweight flywheel & shift pins - w/ Feedback + Video

Post by pingu »

Has anyone fitted one, or have one fitted?

I had one on a Mini engine and it made a phenomenal difference. 1500-6500 rpm in a flick of the ankle :D .

I've done some investigations and this seems to be as good as any - ACT Flywheel and Clutch

There will be some more things to buy, such as 12.9 grade bolts (and the dreaded import duty), but until the box arrives I won't know what's missing.


I'll also be doing the shift pins while the gearbox is off. Hopefully it will help the gear change.
Last edited by pingu on Tue 17 Mar, 2015 23:01, edited 3 times in total.
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Dino D
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  Z3 roadster 2.8

Re: Lightweight flywheel and clutch

Post by Dino D »

I have read somewhere (I think on a US forum) that fitting a 320 clutch and flywheel to the 2.8 is a good cost effective mod along these lines... Apparently fits but there is a 'tab' that needs to be grinded off or something.
swamper
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Re: Lightweight flywheel and clutch

Post by swamper »

have you got some sort of issue Pingu or just modding?
the badness makes me do it...!

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Deano1712
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Re: Lightweight flywheel and clutch

Post by Deano1712 »

Go for it pingu. Good mod, but will be easy to stall it. Do the 6-speed while you are in there then no need to mess with the pins.
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pingu
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Re: Lightweight flywheel and clutch

Post by pingu »

Deano1712 wrote:Go for it pingu. Good mod, but will be easy to stall it. Do the 6-speed while you are in there then no need to mess with the pins.
The "issue" is that the plate was down to 1mm when I had the box off nearly 2yrs ago :shock: .

I've considered doing the 6-speed thing, but I don't drive the car enough to justify it.

If I've got to change the clutch and spend £600, I'd might as well get some REAL benefit out of it :D .

I'm considering getting the manifolds ceramic coated, but if I'm going to do it properly it will cost around £800 (http://www.zircotec.com/page/--performance-colours/47)
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siwilson
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Re: Lightweight flywheel and clutch

Post by siwilson »

Lightweight flywheels can make a horrible rattling noise. JasonZ3M had one on his highly modified S50. It was amazingly responsive to the throttle, but clack clack clack all the time.
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pingu
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Re: Lightweight flywheel and clutch

Post by pingu »

siwilson wrote:Lightweight flywheels can make a horrible rattling noise. JasonZ3M had one on his highly modified S50. It was amazingly responsive to the throttle, but clack clack clack all the time.
The clack clack clack is "chatter" in the gearbox. The main purpose of a flywheel is to dampen the engine pulses. "Lightening" the flywheel reduces the damping effect. Like everything on a car, it is a compromise between performance, refinement and economy. I'm prepared to forego refinement and economy :twisted: .

The chattering in the gearbox can be reduced by overhauling it and making sure all the tolerances are as tight as blueprinting will allow.

When I get the new flywheel assembly I hope to do a simple experiment to show the difference between it and the OEM flywheel assembly.


"Lightening" when referring to flywheels means reducing the "Mass Moment of Inertia". DO NOT confuse this with the mass of the flywheel. The moment of inertia has more to do with how the "weight" is distributed than the "weight" itself.

Mass Moment of Inertia = Mass x (Effective Radius)^2

If the material can be concentrated close to the centre of rotation, the Mass Moment of Inertia will be reduced, BUT the damping effect is also reduced - hopefully not by too much :shock: .
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pingu
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Re: Lightweight flywheel and clutch

Post by pingu »

Happy Chrimbo to me.

For $1300, it had better be worth it :shock: .
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bertiejaffa
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Re: Lightweight flywheel and clutch

Post by bertiejaffa »

pingu wrote:Happy Chrimbo to me.

For $1300, it had better be worth it :shock: .
Looking forward to giving you a hand :wink:
Here come the girls.....
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pingu
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Re: Lightweight flywheel and clutch

Post by pingu »

bertiejaffa wrote:
pingu wrote:Happy Chrimbo to me.

For $1300, it had better be worth it :shock: .
Looking forward to giving you a hand :wink:
At what point do you want to get involved? I think the best time to come over is when the box is out and both flywheels are on the floor. I can show you what needs done - you don't need to actually be here for the removal or replacement of the box, but it's good to see what needs to be done and how to do it (tools, etc.).

I anticipate that replacing the shift pins will only take an hour or two at the most.

It's about 15-20 hours work to do the whole job, but it will take me upto a fortnight to do as
a) I need to fit it in around work and can be called away at any time for any amount of time (I could end up in Scotland for a week because of a phone call I get in five minutes :shock: )
b) I work outside
c) I don't mind the cold, but I don't work in the rain / snow / wet.
d) I'm in no rush

The shift pins can be done in the garage, so there's no need to wait for a weather window to do them.

I'll phone you when I'm ready to start.
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ragerover
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Re: Lightweight flywheel and clutch

Post by ragerover »

Just seen this thread so not sure if you've done it yet if so ignore my advise

IVe done a few of these so hope I can be of help

If you've got all the parts it won't take 20 hrs I'd recon you could do it in a day on ramps or axle stands
I went for UUC. Quality kit
Depends on what model your car is on the actual clutch you use
You will get chatter but you can change the gearbox oil which helps a bit does not totally eliminate even with a fully rebuilt box
Easiest way I'd say is try and borrow a pit or a 2 poster you will do it in 6 hrs tops
Or you could source the bits and get a local garage/ Indy to do it
It's not rocket science
If you need any advice I'm always on z3mcoupe.com
Very rarely on here
My sons got an Indy and does 6 speed conversions too
So give me a shout if you need any help or advice
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pingu
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Re: Lightweight flywheel and clutch

Post by pingu »

ragerover wrote:Just seen this thread so not sure if you've done it yet if so ignore my advise

IVe done a few of these so hope I can be of help

If you've got all the parts it won't take 20 hrs I'd recon you could do it in a day on ramps or axle stands
I went for UUC. Quality kit
Depends on what model your car is on the actual clutch you use
You will get chatter but you can change the gearbox oil which helps a bit does not totally eliminate even with a fully rebuilt box
Easiest way I'd say is try and borrow a pit or a 2 poster you will do it in 6 hrs tops
Or you could source the bits and get a local garage/ Indy to do it
It's not rocket science
If you need any advice I'm always on z3mcoupe.com
Very rarely on here
My sons got an Indy and does 6 speed conversions too
So give me a shout if you need any help or advice
Thanks for the offer. The time I've given includes "faffing around". I've done it before and could do it in a day if I had to, but it's not a race.

The clutch is in the UK and is awaiting clearance, so I should get a bill from customs soon :( .
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pingu
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Re: Lightweight flywheel and clutch

Post by pingu »

Clutch is here...
Image
Image

Exhaust is off, propshaft is off, gearbox should be off tomorrow (if it doesn't rain) :D .

Spares needed so far are propshaft nuts, exhaust gaskets, exhaust nuts and a gear linkage bush.
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pingu
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Re: Lightweight flywheel and clutch

Post by pingu »

Ground was wet yesterday, so just did the work needed in the engine bay. So, fan off, plenum off and starter motor off. Sounds easy, but it's really fiddly with very limited access.

Also started making a bifilar pendulum to measure the mass moments of inertia of the two flywheels.
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pingu
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Re: Lightweight flywheel and clutch

Post by pingu »

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Smartbear
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Re: Lightweight flywheel and clutch

Post by Smartbear »

Hmm, is that the same as saying the engine will be 13% more responsive? Or will it have 13% less torque? Interested to read your opinion after driving it :drive
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pingu
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Re: Lightweight flywheel and clutch

Post by pingu »

Smartbear wrote:Hmm, is that the same as saying the engine will be 13% more responsive? Or will it have 13% less torque? Interested to read your opinion after driving it :drive
Regards
The engine should be more responsive, but not by 13% as the front damper, crankshaft, con-rods or pistons have not been touched. Torque and power will not be affected.

It's like putting a lighter seat in the car that is 13% lighter than the old one. You should attack the largest contributor to the problem. With weight, it may be the seats; with rotation, it's the flywheel or the wheel/tyres.

All the rotating parts add up to the overall MMI. As a contributing part to the engine, it will be a large contributor (probably the largest), but as a contributor to the Engine / Gearbox / Propshaft / Differential / Driveshaft / Brake Disc / Wheel / Tyre combination it will be quite small, but every little helps.

It probably produces the greatest saving for an individual component, other than the wheels. Reducing the MMI of the Wheel / Tyre combination probably makes the greatest saving (especially as this will also reduce unsprung weight and gyroscopic effects), but I have my reasons for not doing the wheels. I want to keep the car looking as standard as possible.
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Brian H
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Re: Lightweight flywheel and clutch

Post by Brian H »

bifilar pendulum! had to google this, every day is a school day :)
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pingu
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Re: Lightweight flywheel and clutch

Post by pingu »

Brian H wrote:bifilar pendulum! had to google this, every day is a school day :)
Ideally, I would have used a trifilar pendulum, but it would have been too difficult to make (I don't have a big enough lathe) and to setup.
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Re: Lightweight flywheel and clutch

Post by gookah »

pingu wrote:
Brian H wrote:bifilar pendulum! had to google this, every day is a school day :)
Ideally, I would have used a trifilar pendulum, but it would have been too difficult to make (I don't have a big enough lathe) and to setup.
I think I have seen these devices on Saw IV.....
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I have an element of 'M-styling' on my car, If that's a good enough reason for the manufacturers to adorn a 320 with the M badge, then its certainly a good enough reason for me..
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pingu
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Re: Lightweight flywheel and clutch

Post by pingu »

gookah wrote:
pingu wrote:
Brian H wrote:bifilar pendulum! had to google this, every day is a school day :)
Ideally, I would have used a trifilar pendulum, but it would have been too difficult to make (I don't have a big enough lathe) and to setup.
I think I have seen these devices on Saw IV.....
I've made a trifilar pendulum. I know that it's really sad, but I'm enjoying myself and not harming anyone - happy days :D
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pingu
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Re: Lightweight flywheel and clutch

Post by pingu »

Shift pins done - kinell. Anyone who says it's easy has either missed something or is a mechanicking God :shock: .
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Deano1712
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Re: Lightweight flywheel & shift pins

Post by Deano1712 »

You're a hero pingu. Good job.
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Joycey
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Re: Lightweight flywheel & shift pins

Post by Joycey »

Pingu I'm just about to undertake the shift pins task at home on my dad's 2.8 his gearbox is like stirring pudding so thought it was about time I sorted it for him.

Did you follow the guide kicking around the net?

And in hindsight what would you of done differently to make it easier?

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pingu
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Re: Lightweight flywheel & shift pins

Post by pingu »

I followed this guide (https://docs.google.com/file/d/0B2J_m2p ... Nzc00/edit). Like all guides, it says things like "remove the bearing". Yes, you do have to remove the bearing, but how do you do it without damaging the gearbox?

The video shows how to overcome the problems I had...
Last edited by pingu on Fri 06 Feb, 2015 21:33, edited 1 time in total.
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c_w
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Re: Lightweight flywheel & shift pins

Post by c_w »

I know you're not the first person to fit a light flywheel, but do you forsee any long term implications with respect to the lack of damping from the single mass flywheel?

On the AUDI forums many are replacing their TDI engine's dual mass flywheel with a single mass flywheel but some are reporting potential damage to the gearbox, but this is a 4cyl diesel rather than the more inherent smoothness of the 6cy petrol engine.
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pingu
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Re: Lightweight flywheel & shift pins

Post by pingu »

c_w wrote:I know you're not the first person to fit a light flywheel, but do you forsee any long term implications with respect to the lack of damping from the single mass flywheel?

On the AUDI forums many are replacing their TDI engine's dual mass flywheel with a single mass flywheel but some are reporting potential damage to the gearbox, but this is a 4cyl diesel rather than the more inherent smoothness of the 6cy petrol engine.
No, but I don't "drop the clutch". IMO, DMFs and CDVs are there to compensate for bad driving techniques. I hope I'm not wrong, but if I am, I'll let the forum know that my gearbox has exploded and can be found at a set of traffic lights next to a laughing chav in his Corsa :D
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pingu
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Re: Lightweight flywheel & shift pins

Post by pingu »

I've just fitted the lightened (solid) flywheel and the car sounds like there is a 50-cal being rapid-fired underneath it :shock: . I've just investigated the noise (by supporting the car and the lower rear arms and biting the clutch in 1st. The diff is twisting by about 2 inches. It's too late to run the car just now (no silencers fitted), but I may post a video tomorrow. I'm pretty sure that I need a double-eared diff cover.

If I reduce the twist of the diff, the forces will be transferred to the floor, so that will need to be strengthened. It goes on and on - constantly chasing the weak point :roll: .

Tomorrow, I'm going to see if I can get an E36 M3 diff bracket (33 17 2 228 128).
Image

If it's cheap enough, I'm going to use it as the basis for a triple-eared diff mount (the original + the two ears from the M3 mount).

[edit] Some people ask if a lightened flywheel adds torque. The answer is no, but the solid flywheel transfers the torque straight to the gearbox (via the very small amount of damping in the clutch plate) rather that the torque being damped by the dual-mass flywheel. If you fit a SOLID flywheel (lightened or not), I think that you need to do something about the direct torque transfer from the engine to the transmission. Think about hanging a bag of sugar on a piece of string, or on a spring. Now lift the bag and drop it. The shock you feel when the bag is dropped on the string is much more than when dropped on the spring. But it's the same bag of sugar - just as it's the same engine.
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pingu
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Re: Lightweight flywheel & shift pins

Post by pingu »



Well, the diff mounting has cracked :head: .

A new one was only £15, so it's on order from Germany.

I hope that nobody needs to buy the rubber mounting. It used to be £25, but it is now £142 :shock: .

The M3 mounting was £30 and doesn't fit, but I'll find a use for it, or put it on eBay.

Someone from another forum has suggested that I may have put the clutch plate on the wrong way round. It is marked with a sticker, so I'm hoping that I've not been a complete numpty, but I will check to make sure.

I also think that I'll be investing in a kit designed by someone who has just returned to the forum after an eleven year break :wink: .
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Deano1712
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Re: Lightweight flywheel & shift pins

Post by Deano1712 »

Whats cracked? I thought you already fixed the boot floor on your car. Im on a single eared cover with 550hp so dont think your clutch change should need you to change that.
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pingu
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Re: Lightweight flywheel & shift pins

Post by pingu »

Deano1712 wrote:Whats cracked? I thought you already fixed the boot floor on your car. Im on a single eared cover with 550hp so dont think your clutch change should need you to change that.
It's the root of the single ear.

Do you have a dual mass, or a solid flywheel? The video is only 30 seconds. If you play it, you can see the diff jerking down whenever the clutch is engaged. The images at the end show the ear and the crack (which has no rust in it, so it's fresh). I've got a new diff suspension mount on order from Germany (only £15). It should be here by the end of next week.

Someone has suggested that I may have put the clutch plate on the wrong way. I'm pretty sure that I haven't done this, but I'll be taking the gearbox off to check.

I've been busy today. Diff off and propshaft off. It's dark now, but if I can I'll look at the clutch tomorrow.
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Deano1712
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Re: Lightweight flywheel & shift pins

Post by Deano1712 »

pingu wrote: It's the root of the single ear.

Do you have a dual mass, or a solid flywheel?
Mine is single mass.

Do you mean this part?
Image
I replaced that when I strengthened my boot floor. The pic is blurred but I welded up the obvious stress raisers on it to try improve its strength. I don't have a record of the material thickness but remember it was marginally thicker than original part - 0.2mm rings a bell.

EDIT - sorry just seen the video - cant imagine whats causing it to jump up and down, doesn't seem right. Does the diff turn ok with the engine off?
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gookah
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Re: Lightweight flywheel & shift pins

Post by gookah »

The way that is jumping, I would have thought more that something is misaligned.
Is it not something to do with just the prop and rubbers?
I would have thought the clutch would not transfer such jerks all the way back though the gearing unless it is seriously grabbing.
can you run it with the gearbox still fitted and no prop to see if it still does it?
can you feel anything back through the pedal via the hydraulics?
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Z3 2.8 Progress Journal (Mine)
Z3 1.9 Sport Progress Journal (Wifey's)

I have an element of 'M-styling' on my car, If that's a good enough reason for the manufacturers to adorn a 320 with the M badge, then its certainly a good enough reason for me..
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Brian H
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Re: Lightweight flywheel & shift pins

Post by Brian H »

It's hard to tell from the video, but the rear beam looks to be solid, I.e. not jumping about.

Question:

How does the diff move so much when it has two bolts holding it to the rear beam?

Also, If you look at the crack in the rear diff bracke at the ed of the video, it seems to have rust inside the crack? This does not look new?
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pingu
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Re: Lightweight flywheel & shift pins

Post by pingu »

Deano1712 wrote:
pingu wrote: It's the root of the single ear.

Do you have a dual mass, or a solid flywheel?
Mine is single mass.

Do you mean this part?
Image
I replaced that when I strengthened my boot floor. The pic is blurred but I welded up the obvious stress raisers on it to try improve its strength. I don't have a record of the material thickness but remember it was marginally thicker than original part - 0.2mm rings a bell.

EDIT - sorry just seen the video - cant imagine whats causing it to jump up and down, doesn't seem right. Does the diff turn ok with the engine off?
Yes, that's the part. I can't believe how cheap the are.

Diff is fine. I've got it off and it's fine.
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Re: Lightweight flywheel & shift pins

Post by pingu »

gookah wrote:The way that is jumping, I would have thought more that something is misaligned.
Is it not something to do with just the prop and rubbers?
I would have thought the clutch would not transfer such jerks all the way back though the gearing unless it is seriously grabbing.
can you run it with the gearbox still fitted and no prop to see if it still does it?
can you feel anything back through the pedal via the hydraulics?
I agree about it having the symptoms of misalignment.

You have given me an idea. I'll turn the propshaft by 90° and see what happens, but I can't do that before I refit the diff.

I'll check the clutch and the gearbox for grabbing.

I'll try the gearbox without the prop on. It's going to be VERY loud as the cat is off now as well as the silencers. I'd best leave that until after dawn to test :D .

No feedback problems with the hydraulics.
Last edited by pingu on Sun 08 Feb, 2015 05:15, edited 1 time in total.
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Re: Lightweight flywheel & shift pins

Post by pingu »

Brian H wrote:It's hard to tell from the video, but the rear beam looks to be solid, I.e. not jumping about.

Question:

How does the diff move so much when it has two bolts holding it to the rear beam?

Also, If you look at the crack in the rear diff bracket at the end of the video, it seems to have rust inside the crack? This does not look new?
The rear beam isn't moving, but there will be excessive twist on the centre section that holds the diff to the beam.

I think the crack is very clean and it's new. All that twist would be making it worse anyway.
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Deano1712
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Re: Lightweight flywheel & shift pins

Post by Deano1712 »

Suggest you should check driveline alignment. Is gearbox mount fitted correctly?
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pingu
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Re: Lightweight flywheel & shift pins

Post by pingu »

Deano1712 wrote:Suggest you should check driveline alignment. Is gearbox mount fitted correctly?
I'm taking everything off. Been out all day today and will be out again tomorrow, so Tuesday at the earliest before I get stuck in - and I've got to do the front wheel bearing on the van as well :shock: .
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Re: Lightweight flywheel & shift pins

Post by pingu »

Everything is off (from the clutch to the diff). Everything looks OK. Gearbox turns smoothly in all gears. Diff turns smoothly. Propshaft looks OK.

I'm a bit confused by it all. I can only put it down to clutch judder as the clutch beds in.

Anyway, I'm using the opportunity to paint the underside of the body and grease the brakepipes, etc. It will be all show and no go :shock: .
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c_w
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Re: Lightweight flywheel & shift pins

Post by c_w »

Was the diff wobbling on drive take up or with the clutch engaged as if driving?

I replaced the clutch flywheel on my AUDI A3 TDI last year; all brand new SACHS stuff and put back together it juddered pretty badly. Setting off the car shook and you could feel it changing in to 2nd and even 3rd. Bad enough to make me think something was wrong as I wouldn't expect clutch judder on a brand setup, especially SACHS - and brand new cars don't suffer clutch judder do they! It was all meticulously clean too. I checked nothing was going to fall off (I suspected/hoped it was just a loose engine mount but it was all ok).

I was advised it probably needed bedding in, which I couldn't understand as it was all brand new with smooth friction faces etc and never had this before on other cars. However, after a bout 2 or 3000miles (yes that long as I it's not driven hard at all) it bedded in nicely and the judder disappeared. I resisted the urge to give it a fast bedding with hard slipping as you run the risk of creating hardened hot spots on the flywheel which will always give judder.
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pingu
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Re: Lightweight flywheel & shift pins

Post by pingu »

c_w wrote:I was advised it probably needed bedding in, which I couldn't understand as it was all brand new with smooth friction faces etc and never had this before on other cars. However, after about 2 or 3000miles (yes that long as I it's not driven hard at all) it bedded in nicely and the judder disappeared. I resisted the urge to give it a fast bedding with hard slipping as you run the risk of creating hardened hot spots on the flywheel which will always give judder.
This sounds EXACTLY the same. I'm going to put a double-eared diff on and then put it all back together (after giving the underside a good painting). I did think about excessively slipping the clutch, but that would create the hot-spots you talked about. I guess I'll just have to persevere.
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Re: Lightweight flywheel & shift pins

Post by pingu »

TADA :D .

I've drilled (3mm) the ends of the cracks on the diff hanger and another crack I found on the crossmember to relieve the stress. Then welded the cracks.

Replaced the flexible coupling - it had some small cracks in it.

Confirmed the clutch was fitted correctly.

Gravity bled the clutch master cylinder.

Confirmed the drive from the front of the engine to the diff was in a straight line using a piece of string.

Finally, the culprit (I think) - the gearshift linkage was fitted the wrong way. The linkage was very close to the flexible coupling and was sometimes touching (but only just). I had connected the lever that goes to the shifter so it was on the left of the car. It should be on the right. I don't remember disconnecting the end that was connected to the gearlever, but I must have done - and then connected it the wrong way round. What a Wally :head:



A point to note when refitting the diff...

Raise the weight of the car off the wheels to connect the four bolts and then put the weight back on the wheels to connect the diff to the diff hanger.
Pingu
Bi11
Joined: Mon 05 Nov, 2012 21:26
Posts: 150

  M roadster S54
Location: Bedford

Re: Lightweight flywheel & shift pins

Post by Bi11 »

Glad you got it sorted. Was a bit worried for you!
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swamper
Joined: Thu 13 May, 2010 17:14
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  M roadster S50
Location: Mossley

Re: Lightweight flywheel & shift pins

Post by swamper »

Good result....now we can hear the review on the lightened flywheel
the badness makes me do it...!

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pingu
Joined: Fri 30 Apr, 2004 16:01
Posts: 3412

  M roadster S50

Feedback

Post by pingu »

Feedback on driving the car

:drive = :thumb:

The shift pin mods works perfectly. 3rd/4th is now the natural position, so a 2 --> 3 change is just a straight push and a 5 --> 4 is straight pull.

The lightweight flywheel makes rev matching VERY easy and almost natural. This is good because the loss of the dual mass flywheel means that there is very little protection from shock loading the transmission, so a bad gear change could be catastrophic. Starting in either 1st or Reverse needs to be done carefully (a few more revs than usual and a bit more clutch slip than before) or the transmission shudders, but it's easy to catch because the revs increase so fast.

Speed of acceleration is hard to tell whether it's faster or not, but it feels faster :D .

I need to video an idle to rev-limiter WOT test just to see how fast it is. It's not the 0.6 seconds of a Nissan GTR, but it will be fast.
Pingu
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c_w
Joined: Thu 19 Aug, 2004 16:50
Posts: 4032

  M roadster S50

Re: Lightweight flywheel & shift pins - w/ Feedback

Post by c_w »

All sounds great (apart from the judder setting off, which may go in time with bedding?). It's always been on my maybe list of modifications, as I can't help but feel the engine feels a bit lazy sometimes.
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pingu
Joined: Fri 30 Apr, 2004 16:01
Posts: 3412

  M roadster S50

Re: Lightweight flywheel & shift pins - w/ Feedback

Post by pingu »

c_w wrote:All sounds great (apart from the judder setting off, which may go in time with bedding?). It's always been on my maybe list of modifications, as I can't help but feel the engine feels a bit lazy sometimes.
The juddering is only slight and can be easily caught and then feeding the clutch is easy as pie.

There are two ways to set off without the judder - feed the clutch properly or the Clarkson way and wait for the rear end to fall off :D .
Pingu
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pingu
Joined: Fri 30 Apr, 2004 16:01
Posts: 3412

  M roadster S50

Re: Lightweight flywheel & shift pins - w/ Feedback

Post by pingu »

Pingu
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