Sachs 765 Pressure Plate on an M20?

[SLEEPYDUB]

Hey guys, my clutch started slipping around 25psi on my M20 using a 6 puck clutch, and I need something that will hold the abuse of clutch kicking in 3rd.

I have read that I can use an M30 or M52/S52 flywheel, an M50 starter, and a Sachs 765 Pressure Plate.

Can anyone break this down for me and tell me exactly which parts from which models I need? Exactly which starter do I need to use? Which Flywheel because some people say M52 and not M50, or has to be M30/S38. I just need confirmation before I purchase. Thanks in advance!

[Northern]

-765 pp is m30/S38 flywheel fitment, or that RHD flywheel that's M30 clutch fitment with 24v starter gear. Rated in the sachs pdf for 437ftlb with an organic disc, or 518 ftlb with a sintered plate.

-792 is S52 flywheel fitment, and rated for 352/organic or 418/sintered. (I've heard of very few people running this one)

-618 is M20 flywheel fitment, and rated for 333/organic or 392/sintered. (but seems to hold almost double that.)

I don't think there's a sachs race plate in M52 fitment.

[SLEEPYDUB]

-765 pp is m30/S38 flywheel fitment, or that RHD flywheel that's M30 clutch fitment with 24v starter gear. Rated in the sachs pdf for 437ftlb with an organic disc, or 518 ftlb with a sintered plate.

Ok so its just that easy then? Get the RHD flywheel, 24v starter, and a 765 and Im good to go? Do you have a link to the different clutch disc that can be used with this combo?

[Northern]

Should be pretty straightforward, I'm just not sure about the disc.

I think Sachs makes sintered and organic discs with their race series pressure plates, but I don't know how they differ from the normal BMW offerings.

I'd definitely go for a sprung hub disc. There's really no power loss, just easier on the hardware to have something sprung in there.

M30/S38 would have 240mm sprung hub discs. Should be easy to find aftermarket organic or sintered clutch discs for it. They would work fine, I'm just not sure if the Sachs Race specific stuff is somehow better.

[Wanganstyle]

Should be pretty straightforward, I'm just not sure about the disc.

I think Sachs makes sintered and organic discs with their race series pressure plates, but I don't know how they differ from the normal BMW offerings.

I'd definitely go for a sprung hub disc. There's really no power loss, just easier on the hardware to have something sprung in there.

M30/S38 would have 240mm sprung hub discs. Should be easy to find aftermarket organic or sintered clutch discs for it. They would work fine, I'm just not sure if the Sachs Race specific stuff is somehow better.

I would actually choose the S52 setup; using 2x of them in 36m/30; both with twincams

1. aftermarket s52 flywheels are easily avail; to attach to m20 just run m50 starter.

2. pressure plate is lighter than s38 unit; if needed aftermarket clutches are many to choose from.

3. sprung hub is not needed with s52 clutch; I have ran both sachs s52 pressure plate with a sprung friction disc and sachs s52 clutch set with un-sprung friction disc; both are mild enough to drive around in san francisco.

4. As far as power holding is concerned; the s52 OEM sachs clutch/unsprung friction disc is easy to drive for all drivers and is good enough to run for the 25hrs of thunderhill + s54 @ 310rwhp; locally proven in endurance use.

[Northern]

3. sprung hub is not needed with s52 clutch; I have ran both sachs s52 pressure plate with a sprung friction disc and sachs s52 clutch set with un-sprung friction disc; both are mild enough to drive around in san francisco.

I'm assuming he's running a single mass flywheel with any of these setups, hence the sprung disc recommendation.

[Wanganstyle]

Sachs 765 Pressure Plate on an M20?

I'm assuming he's running a single mass flywheel with any of these setups, hence the sprung disc recommendation.

Like I stated:

S52 Oem presssure plate and
UNsprung s52 friction disc
+ single mass flywheel

In BOTH of my cars (e30 m54/ e36m) is ok to daily drive in San Francisco.


The difference between a spring loaded friction disc and non with the same single mass flywheel and s52 pressure plate is almost moot.

[Wanganstyle]

Sachs 765 Pressure Plate on an M20?

Please delete

[Northern]

A sprung clutch disc or flywheel has nothing to do with holding power, so there's zero reason to pair the two solid parts together...

The crankshaft accelerates in an oscillation from the 3 combustion events per revolution, and the springs just damp these acceleration events.

Removing the sprung disc/flywheel just causes them to be passed on through the transmission. Between lash and the guibo they probably disappear quickly, but considering the springs in the discs fail so rarely, there's no advantage gained by running a solid disc, only potential for ever-so-slightly more wear on the clutch and transmission.


I understand that you'll likely disagree with this, and that's fine.

[ForcedFirebird]

Like I stated:

S52 Oem presssure plate and
UNsprung s52 friction disc
+ single mass flywheel

In BOTH of my cars (e30 m54/ e36m) is ok to daily drive in San Francisco.


The difference between a spring loaded friction disc and non with the same single mass flywheel and s52 pressure plate is almost moot.

I can agree this works, and works fine. But as Northern said, you really want the dampening somewhere IMO. It's splitting hairs, but don't you agree your transmission bearings will be a little happier with dampening?

Some people don't care about idle clutch rattle #becauseracecar, and some people will cry at a squeak from a trailing arm bushing - so some of this topic is subjective YMMV.

[The Dark Side of Will]

Bearings give zero fucks.

Also:

Damped:


Dampened:

[Wanganstyle]

I can agree this works, and works fine. But as Northern said, you really want the dampening somewhere IMO. It's splitting hairs, but don't you agree your transmission bearings will be a little happier with dampening?

Some people don't care about idle clutch rattle #becauseracecar, and some people will cry at a squeak from a trailing arm bushing - so some of this topic is subjective YMMV.

the transmission cares a lot more about the fact that its original dual mass flywheel was replaced by a solid piece; the undamped friction disc is native to the transmission.

both e36m and e30 are dohc 24v single vanos; none of these had a native single mass

but in reality it does not care at all. 286k miles original vin matching transmission to engine and body

[The Dark Side of Will]

The ONLY function of the sprung hub disk is to reduce gear rattle in the transmission.

It does *NOT* affect torque transients through the driveline in any way.

The springs bottom out with comparatively little torque applied to the disk. A sprung hub disk doesn't cushion anything in any meaningful way.