Clutch ideas? UUC says mine isn't "right" for my application

[jicaino]

Just drained the trans, and something very thin, light brown and smelling of a chinese shoe came out.

Just removed the CDV, and I can see straight through it. Doesn't appear there was ever anything inside of it, so I have to assume someone already did option A, and I'll be pulling this UUC clutch and replacing it, which I really was hoping to avoid. The way this project is going, this car will be on the lift until Christmas.

chinese shoe!

That's ATF.

As for the CDV, the restriction isn't that big, it's just a restriction. How large is it inside? (a rough ballpark is fine, like, sticking a drill of a known size and see what fits and what not)

[ThaDoubleJ]

Alright, researching the M5 clutch swap, tell me if I've got this right: E39 has the reluctor on the flywheel, M5 and 540 are different, so you have to stick with the 540 flywheel and then bolt the M5 friction disc and pressure plate to it, which are more grabbier and have a stronger holding spring. Problem being of course, I don't have a 540 flywheel, I have this UUC hoo-ha, so I'll have to source everything. Sound about right?

Calipers say .150", CDV is basically wide open

[jicaino]

Alright, researching the M5 clutch swap, tell me if I've got this right: E39 has the reluctor on the flywheel, M5 and 540 are different, so you have to stick with the 540 flywheel and then bolt the M5 friction disc and pressure plate to it, which are more grabbier and have a stronger holding spring. Problem being of course, I don't have a 540 flywheel, I have this UUC hoo-ha, so I'll have to source everything. Sound about right?

Calipers say .150", CDV is basically wide open

Yeah, the CDV has been... err... "reamed open" Name her Mia K.

The 540i and M5 flywheels are about the same and crank triggering point/location, the M5 one is heavier so probably the lighter 540i it's a better choice (plus a lot cheaper since it's not taxed by the ///M badge overpricing policy of BMW parts) If you get a good twin mass flywheel that's being "upgraded" maybe you can score a M5 one for cheap?

[H3adBussa]

Alright, researching the M5 clutch swap, tell me if I've got this right: E39 has the reluctor on the flywheel, M5 and 540 are different, so you have to stick with the 540 flywheel and then bolt the M5 friction disc and pressure plate to it, which are more grabbier and have a stronger holding spring. Problem being of course, I don't have a 540 flywheel, I have this UUC hoo-ha, so I'll have to source everything. Sound about right?

Calipers say .150", CDV is basically wide open

Yup, you use the 540 dual mass flywheel with the M5 clutch.

Sent from my SM-G975U using Tapatalk

[blarf]

Alright, researching the M5 clutch swap, tell me if I've got this right: E39 has the reluctor on the flywheel, M5 and 540 are different, so you have to stick with the 540 flywheel and then bolt the M5 friction disc and pressure plate to it, which are more grabbier and have a stronger holding spring. Problem being of course, I don't have a 540 flywheel, I have this UUC hoo-ha, so I'll have to source everything. Sound about right?

Calipers say .150", CDV is basically wide open

Yes. M5 clutch kit, 540 flywheel. Dual mass flywheels are basically one use only, don't bother resurfacing them. It's an extremely streetable setup. If you want to keep the flywheel why not try a stock 850CSi clutch kit?

Dunno how abused my transmission is versus yours but if the ambient temperature is much under 80° I've got to be very gentle with second gear (this is with MTF-LT-2 fluid).

[jicaino]

Yes. M5 clutch kit, 540 flywheel. Dual mass flywheels are basically one use only, don't bother resurfacing them. It's an extremely streetable setup. If you want to keep the flywheel why not try a stock 850CSi clutch kit?

Dunno how abused my transmission is versus yours but if the ambient temperature is much under 80° I've got to be very gentle with second gear (this is with MTF-LT-2 fluid).

Not a matter of abused as much as how old she is. Have you checked if your 420G has the newer ZF detents or if it has the older ball and spring detents?

[ThaDoubleJ]

Since I don't have any stock parts, I'd have to source all this M5 stuff new I think. Something tells me that'd get expensive. How about these Clutch Masters kits? Price is tolerable, reviews seem good and I could probably sell the UUC for what the CM costs, then just do it all in one go.

420G? ZF detents? Ball and spring? Is that something I can check while the trans out out for the clutch job? Damn I don't want to pull the trans, some of those bellhousing bolts are WAY up in there.

[jicaino]

Since I don't have any stock parts, I'd have to source all this M5 stuff new I think. Something tells me that'd get expensive. How about these Clutch Masters kits? Price is tolerable, reviews seem good and I could probably sell the UUC for what the CM costs, then just do it all in one go.

420G? ZF detents? Ball and spring? Is that something I can check while the trans out out for the clutch job? Damn I don't want to pull the trans, some of those bellhousing bolts are WAY up in there.

Yeah, ideally done with the trans off as you need access to several plugs that are on the top and all. I think I have the PN for the repair kit somewhere.

[ThaDoubleJ]

This: https://www.ecstuning.com/b-genuine-...11228393detkt/

For this? For vehicles with S6S420G transmission only

[jicaino]

This: https://www.ecstuning.com/b-genuine-...11228393detkt/

For this? For vehicles with S6S420G transmission only

This is one of them. There's 2 kits. This goes on the ph side of the transmission near and above the clutch slave. The other one goes on the tail, up top, right side, and has a cover with 2 bolts.

Derents: 23317506947

Here's realoem diagram. Older transmissions have falls and springs

https://www.realoem.com/bmw/enUS/sho...diagId=23_0221

[blarf]

Not a matter of abused as much as how old she is. Have you checked if your 420G has the newer ZF detents or if it has the older ball and spring detents?

True. I'm kicking myself for not replacing the detents when I had the transmission out. The shifter is just nasty. Third gear is pretty mushy. Getting into the reverse gate usually takes a ton of effort.

But the second gear synchro is just the nature of the beast. Below about 80° it's just crunchy until the transmission gets some heat into it. Take a look at Harry Metcalfe's review of a de-SMG'd M3 CSL. Even new these boxes were known for being balky when cold.

Since I don't have any stock parts, I'd have to source all this M5 stuff new I think. Something tells me that'd get expensive. How about these Clutch Masters kits? Price is tolerable, reviews seem good and I could probably sell the UUC for what the CM costs, then just do it all in one go.

As I replied earlier I had a Clutchmasters kit (FX100) in the 323 and hated it. It was so stiff and so grabby that the first time I took the car to get smogged the guy stalled trying to move it across the level, epoxied floor. Garbage. I only know one person who didn't hate that clutch and I ended up giving the car to her.

The CSi clutch is different from the M5 one. UUC sells a kit with the factory CSi kit + their flywheel. IMO unless you're actually breaking stuff I'd say with an OE or OEM kit. For the street, aftermarket stuff doesn't even come close.

420G? ZF detents? Ball and spring? Is that something I can check while the trans out out for the clutch job? Damn I don't want to pull the trans, some of those bellhousing bolts are WAY up in there.

http://bmwfans.info/parts-catalog/E3...hifting_parts/

There's a lot of other while you're in there crap you may as well replace. The @$#@! input shaft guide tube is at the top of the list.

[ThaDoubleJ]

Are all these detents something that should be done regardless, or only if there's an issue? I live in dry Colorado, car has always been here, garaged and probably not driven in the weather. Trans shifts great.

ECS says this guide tube should always be replaced with the clutch, but no kits include it. That's weird.

Blart, I think I'm going to avoid all things UUC at this point. Selling 1700 dollar clutches that can't hold power from a stock, 20 year old car at 5500 feet altitude and then trying to sell me a 3300 dollar clutch instead, pass.

I'd be ok with a stock M5 clutch if I still had my flywheel, but at 700 bucks for a single use flywheel, I think I'll just go with the unicorn fart stuff, just hopefully not a stinky one. What did CM say when you contacted them about that clutch? That's supposed to be the stockest one they make

[blarf]

The 850 CSi kit is a factory piece, which is why it might be appealing if you keep the UUC flywheel. I never bothered to reach out to Clutch Masters because I knew I'd never be happy with it. Sprung hub clutch or not it was too noisy. At the time I thought Blanton might still be rebuilding the Getrag five speeds.

The guide tube and shift pins are transmission out services hence while you're in there (along with the selector seal and clutch fork). Your tolerance for pulling the transmission will determine whether or not you do the work. The input tube has a non-stick coating on it so you don't grease the throw out bearing, but the coating wears away with time. If you're already driving the car you'd know if the shifter needs work.

[ThaDoubleJ]

I asked the UUC rep if I could somehow upgrade with the flywheel I have, he said it only works with that setup, and for either the V12 sized kits or the twin disc, I'd have to replace everything.

ECS sells this JB racing setup, aluminum flywheel with a stock pressure plate and disc. I've got an email out them about mix n matching me a 540/M5 hybrid kit, we'll see what they say.

I'm not thrilled about pulling the trans, so it'll be a one time thing if I can help it, looks like the car will be down through the winter at this point any way, so I might as well just do all this stuff.

[jicaino]

I asked the UUC rep if I could somehow upgrade with the flywheel I have, he said it only works with that setup, and for either the V12 sized kits or the twin disc, I'd have to replace everything.

ECS sells this JB racing setup, aluminum flywheel with a stock pressure plate and disc. I've got an email out them about mix n matching me a 540/M5 hybrid kit, we'll see what they say.

I'm not thrilled about pulling the trans, so it'll be a one time thing if I can help it, looks like the car will be down through the winter at this point any way, so I might as well just do all this stuff.

I'd buy an OEM dual mass flywheel and M5 clutch kit with lifetime warranty.

[philly98540]

If you don't want any gear chatter at idle or when you lug the engine under 1500 rpms, you should get the stock LuK dual mass flywheel made for the 540 and the M5 clutch kit(as already recommended). The M5 flywheel has the timing teeth in the wrong spots and wont work. It will hold your target horsepower just fine, will engage wonderfully, and will will have zero gear chatter noises. I had this setup and on my car for a while and loved it. IIRC, it was holding like 475-500 whp nicely. Great setup. It started to slip once I got over about 500 WHP.

If you go with ANY aftermarket single mass flywheel, you will get gear chatter noises when the trans gets warm (even after mixing up special oils to try to eliminate it). The special mix recommended by UUC helps a bit, but chatter is still there when warmed up. The lighter the flywheel, the worse the chatter, but all single mass FW's will do it. Just press the clutch to make it go away if it bothers you.

I don't like UUC as a company, but currently have their pricey twin disc on my car (got it on sale). It holds all the power very good, drive feel is pretty close to stock, but creates some gear chatter noises (single mass FW) when hot at idle and lugging under 1500 rpms. Also some engagement bark noise if I rev up a bit on take off. Not many options out there for this car with high power, so I went UUC.

[ThaDoubleJ]

I don't mind a little noise in the lower rev range, but I do like how the engine revs with the UUC flywheel. I don't believe these cars have rev hang like my Subaru did (which pretty much made it's LW flywheel sound like it weighed 174lbs).

I heard back from CM, they say my car will eat the FX250 once it's supercharged and recommended the FX400 8 pad (puck). My research has led me to the following with aftermarket clutches: 50% hate them, 50% love them, 50% hate them when new but grow to love them, 50% love them when new but burn them up in 1100 miles (or 2500kms, I really need to learn metric in my head). I know that's 200%, but I feel it's accurate.

A company called Spec is universally loved, but M5 fitment only, and I've not come across any post from a BMW owner using one.

ECS emailed me back as well with a pre-filled shopping cart full of a LWFW and stock M5 LuK pressure plate and disc. I'm going to research the flywheel, and if it's round and balanced (steel is replaceable) I'll probably go that way, best of both worlds, no?

It's out of stock till October, booo.

Friction disc appears to be un-sprung on the LuK, but who knows if these are stock pictures, if that's A: True (Confirmed, watched a bunch of YT videos just now, not a spring present) B: A problem with a LWFW (chattery engagement and such so it sounds like my car is broken) C: Will actually break stuff further down the driveline.

Does the LuK clutch have a SAC? I hear that thing sucks. Certainly looks like it does have one.

[jicaino]

Luk clutch for the M5 has a non sprung disc and a SAC pp. It doesn't sucks. I don't know about a lwfw with that combo.
Any lwfw with a biting harsh clutch kit will wear fast, very fast even. I'd stick to 540i dual mass flywheel and stock m5 clutch kit. I recently flipped a M5 I got dirt cheap. No one would buy it. It had hawk pads, stoptech rotors and a crummy UUC clutch with unicorn BS bushings in the shifter and in the rear subframe, plus a really really obnoxious exhaust with no x or h balance pipe and non resonated. Car felt like trash. Went back to stock brakes, stock clutch and a stock exhaust minus cats, sold it in less than a week. Moral of the story is this: performance upgrades are rarely an upgrade and almost never improves performance.

[ThaDoubleJ]

My main beef with the stock dual mass is that it's a single use throw away. I don't plan on using it up, but who knows? I don't have much beef with the light ones, the rattle is a little irritating, but I can live with it. Replaceable friction disc is good, and I won't lie, I like the revvy race car noises - I'm that revvy guy when pulling out, down shifting, sitting, going through tunnels, etc. Just need to find out if I'll be dealing with chattery and breaky stuff. It's interesting that my Subaru came with a dual-mass originally, had a light weight in it when I bought it, swapped it out for a single mass regular weight when I sold it, no idea if the center was sprung or not, and it worked like a top. I was making maybe 75 horsepowers over stock, 100 torques through 3 wheels and it was easy enough for gramma to drive. Same mods to the BMW raise all sorts of questions and I have no front axles.

[jicaino]

My main beef with the stock dual mass is that it's a single use throw away. I don't plan on using it up, but who knows? I don't have much beef with the light ones, the rattle is a little irritating, but I can live with it. Replaceable friction disc is good, and I won't lie, I like the revvy race car noises - I'm that revvy guy when pulling out, down shifting, sitting, going through tunnels, etc. Just need to find out if I'll be dealing with chattery and breaky stuff. It's interesting that my Subaru came with a dual-mass originally, had a light weight in it when I bought it, swapped it out for a single mass regular weight when I sold it, no idea if the center was sprung or not, and it worked like a top. I was making maybe 75 horsepowers over stock, 100 torques through 3 wheels and it was easy enough for gramma to drive. Same mods to the BMW raise all sorts of questions and I have no front axles.

That "single use" thing is BS. Dual mass flywheels can re be repaired and resurfaced, it takes a litte more effort so many shops wouldn't do it, but it's certainly doable. In fact there's a copmany that sells an enlightened dual mass (OE Luk that's been lathed down to about 5 to 7 kilos less than the OE) as the "ultimate flywheel".

- - - Updated - - -

I'm sure any LWFW it's throw away too, my chromoly "heavy duty" LWFW looked a million bucks, but I wouldn't even dare resurfacing it. Dual mass OE flywheels, on the other hand, have a LOT of meat to resurface them, lighten them and reuse them.

[ThaDoubleJ]

My understanding is that you replace the steel disc on the aluminum flywheels if they need to be freshened up.

I found this - 1200 bucks - https://www.einhornindustries.com/st..._M62TU%29.html

Comes in around 31 lbs vs 40.

That's alotta money. Dinan has one too, but only for the M5, 1800 bucks.

[blarf]

That "single use" thing is BS. Dual mass flywheels can re be repaired and resurfaced, it takes a litte more effort so many shops wouldn't do it, but it's certainly doable. In fact there's a copmany that sells an enlightened dual mass (OE Luk that's been lathed down to about 5 to 7 kilos less than the OE) as the "ultimate flywheel".

Hard disagree. When I took the 323 to the shop to get the clutch replaced the guy said he used to resurface them until he had a few comebacks in a row. The car had about 120,000 mi on it but would shudder badly from a stop. Judging by the 32 mpg average the OBC showed *after* I'd had it for a while and finally retrofitted the stalk those were almost exclusively highway miles. The clutch grabbed just fine and a postmortem didn't show any abnormal wear on the friction surfaces. I'd already replaced the center bearing and the flex disc and the conclusion I came to was that the flywheel failed internally. I went with the FX100 + steel flywheel in hopes of having something cheaper, streetable, and not disposable. Instead I ended up with something loud as hell and really obnoxious to drive in traffic.

I'm sure you can resurface and reuse a dual mass flywheel with skill and some luck, but it's not worth it for a shop that's got to eat the cost of a potential failure and IMO not worth it as a DIYer either unless you enjoy dropping the transmission for fun. It's not just about getting a smooth surface, there are moving parts inside the flywheel that wear out.

The aluminum LWFWs Clutchmasters sells have replaceable friction material and the steel one I used was heavy enough (18 lbs?) I'm sure you could shave it down once or twice. But why? Unless you're making too much power for an OE clutch or tracking the car the chatter and rattle are ridiculous and aftermarket friction materials simply aren't as streetable.

[blarf]

Yes the LuK clutch discs are not sprung because they're designed to be used with a dual mass flywheel. A lightweight single mass flywheel with a sprung hub clutch (e.g. FX100) will still make a ton of noise. After about four or five years the FX100 in the 323 finally broke in a bit and was easier to modulate but was still exceptionally stiff. You'd think San Francisco traffic would've broken it in earlier but I guess not. For the record it always slipped a bit with high RPM shifts (smelled like waffles). The people at Clutchmasters have no idea what they're talking about and have clearly used their own products.

I expect the difference between the Subie and BMW is that the rice rocket crowd already expects their cars to be harsh and buzzy. Rice rockets are all about being loud and obnoxious, and you're probably not going to hear the gear rattle over the fart cannon anyways – I can't hear myself think every time my vape tard neighbor with the WRX goes by. If that's what you're going for, go with an aftermarket clutch. Otherwise you're overthinking it. There's no magic unicorn clutch setup that you're going to discover.

With your power goals and a $1,200 budget an OEM setup is a no-brainer. Don't get me started on the garbage Dinan sells I have enough of it on the 540 to know better.

[ThaDoubleJ]

Subies are economy cars, no doubt about that. Mine was a Forester, so a bit more refined (and completely invisible to the police) than a Rex or STI, but with the same engine/trans/drivetrain/suspension so it was easy to modify into a sleeper. No fart can though, not a fan of those.

Noises I can handle. What I wonder is will the LWFW/stock disc/stock plate setup make me roll away from a stop funny or break stuff if I roll away from a stop with the rear tires spinning? The only (stockish) sprung center disc I can find was sold by Turner about 10 years ago, doesn't seem to be a thing anymore. Maybe that unicorn Einhorn thing is the way to go. What's 400 bucks, right? Tank of gas in my Silverado pretty soon the way things are going.

[jicaino]

Hard disagree. When I took the 323 to the shop to get the clutch replaced the guy said he used to resurface them until he had a few comebacks in a row. The car had about 120,000 mi on it but would shudder badly from a stop. Judging by the 32 mpg average the OBC showed *after* I'd had it for a while and finally retrofitted the stalk those were almost exclusively highway miles. The clutch grabbed just fine and a postmortem didn't show any abnormal wear on the friction surfaces. I'd already replaced the center bearing and the flex disc and the conclusion I came to was that the flywheel failed internally. I went with the FX100 + steel flywheel in hopes of having something cheaper, streetable, and not disposable. Instead I ended up with something loud as hell and really obnoxious to drive in traffic.

I'm sure you can resurface and reuse a dual mass flywheel with skill and some luck, but it's not worth it for a shop that's got to eat the cost of a potential failure and IMO not worth it as a DIYer either unless you enjoy dropping the transmission for fun. It's not just about getting a smooth surface, there are moving parts inside the flywheel that wear out.

The aluminum LWFWs Clutchmasters sells have replaceable friction material and the steel one I used was heavy enough (18 lbs?) I'm sure you could shave it down once or twice. But why? Unless you're making too much power for an OE clutch or tracking the car the chatter and rattle are ridiculous and aftermarket friction materials simply aren't as streetable.

You could also get a failed unit, sometimes it happens. The shudder wasn't probably the flywheel, but I don't weigh in with opinion based on rabbits out of my butt. I've refurbished lwfw. Not hard, not unsafe, and if you knownwhat ate you doing, sometimes you can make them better than new. I sometimes buy "single use" dual mass flywheels and refurb them for a quick cash injection.