Driveline upgrade M635csi

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GazM3
Posts: 1791
Joined: Wed Oct 26, 2011 12:55 pm
Location: Melbourne, Australia

Driveline upgrade M635csi

Post by GazM3 »

After I reckon a 4 year hiatus I’m finally doing some works on my m635csi.

some time ago my 280 gearbox failed so I quickly replaced it with the dogleg box and a changed the diff to a more reasonable 3.46. Clutch has been slipping past few years progressively getting worse to the point it needs to be changed. As the gearing was still pretty short (approx 2950rpm@100kmh).

Originally I was going to use a 260 getrag with the stock 3.73 diff but both first and 2nd looked short with a big gap to 3rd. I had my old large case ratio 3.23:1 from my m3 so doing the maths it matches well to the dogleg, and 100kmh at a more reasonable 2650rpm with a taller first and 2nd making them more usable. Like everything one small job snowballs into multiple jobs. A quick summary:

Gearbox: getrag 265/5dogleg with uuc adjustable shifter
Clutch: custom Spring centre segmented with altered pressure plate using 11lb flywheel

Diff: large case with 3.23 ratio, altered ramp angles on pressure ring, shimmed clutches, new bearings & seals.

Driveshaft/cv joints: all refreshed with new dust boots, degreased, new bearings

Shocks: rear shocks rebuilt bilstein HD

Bushes: new adjustable urethane control arm bushes to finally correct the toe and -3.5deg camber


These upgrades should make a world of difference and really enhance the enjoyment of the car.
BMW’s
84 E24 M635csi
90 E34 M5 3.6
94 E34 540i/6 SC E85
97 E36 M3 euro SC U/C
97 Z3 2.8 widebody

OTHERS
11 Audi S5 3.0 SC
19 VW Amarok V6
baders
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Re: Driveline upgrade M635csi

Post by baders »

Nice Gaz ! I prefer the 3.07 behind my dogleg and S38B36 as she has plenty low down torque and very quick top end :) Looking to also correct rear camber since the suspension upgrades, just need to sort out how best to do it.
1986 635csi LOCUTUS / Arktis Blau Metallic / Pearl Beige / S38B36/ Close ratio dogleg 5sp
2002 E46 M3 / Topaz Blau Metallic / Black Nappa / 6 speed SMG software tuned / Bilstein PSS10 Coilovers / CMP RACP reinforcement
GazM3
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Joined: Wed Oct 26, 2011 12:55 pm
Location: Melbourne, Australia

Re: Driveline upgrade M635csi

Post by GazM3 »

I’ll report soon on the kMac bushes. I used them on the e34 and it totally transformed the way it handled.

I thought Of a taller diff as I had a 3.15, but it told me that first had going going to peak around 76kmh and 2nd around 117 or so. I think though the 3.23 with a tight functioning lsd will be much better than a 3.46 with a sloppy lsd that barely functions as one.
BMW’s
84 E24 M635csi
90 E34 M5 3.6
94 E34 540i/6 SC E85
97 E36 M3 euro SC U/C
97 Z3 2.8 widebody

OTHERS
11 Audi S5 3.0 SC
19 VW Amarok V6
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jps635
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Re: Driveline upgrade M635csi

Post by jps635 »

Hi Gaz. Weclome back, you've been missing a while.

Baders, I have the rear K Macs - they do a good job of correcting the rear camber squat with Bilstein sports / H&R's, but do stiffen things up a bit.

Replaced the below tyres late last year - 255/40/17 on 9" RC ET22 rims with 15mm spacers. 35,000 k's over 6 years. Very even wear across the tyre, but still a small bevel on the inside corners.
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'85 635csi JPS (RA2-66)
baders
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Re: Driveline upgrade M635csi

Post by baders »

Thanks chaps, I'd appreciate any info on the Kmac bushes, installation etc.
1986 635csi LOCUTUS / Arktis Blau Metallic / Pearl Beige / S38B36/ Close ratio dogleg 5sp
2002 E46 M3 / Topaz Blau Metallic / Black Nappa / 6 speed SMG software tuned / Bilstein PSS10 Coilovers / CMP RACP reinforcement
GazM3
Posts: 1791
Joined: Wed Oct 26, 2011 12:55 pm
Location: Melbourne, Australia

Re: Driveline upgrade M635csi

Post by GazM3 »

Well things are starting to take shape.
Diff redone and back in car
Rebuilt bilstien sport shocks done and back in place.
Bushes removed (10 tonne press reqd)
Cv joints redone
Clutch/flywheel/pressure plate removed and sent to direct clutch in QLD

Both the flywheel and pressure plate were heavily scored with still a reasonable amount of friction material left on the clutch plate so perhaps pressure plate fingers lost tension. Anyway it will be sorted.

Yes it seems ages since playing with the m635csi. It’s had a slipping clutch for about 3yrs now. I’ve been busy playing with my e34 540i manual that’s now supercharged and running 16psi of boost and straight E85, and also a little golf yellow 2002 came into my life unexpectedly which has taken some time, cash, and attention. It’s hard having like 3 project cars all going simultaneously. Can’t wait to have the e24 back on the road and driving sweet.
BMW’s
84 E24 M635csi
90 E34 M5 3.6
94 E34 540i/6 SC E85
97 E36 M3 euro SC U/C
97 Z3 2.8 widebody

OTHERS
11 Audi S5 3.0 SC
19 VW Amarok V6
GazM3
Posts: 1791
Joined: Wed Oct 26, 2011 12:55 pm
Location: Melbourne, Australia

Re: Driveline upgrade M635csi

Post by GazM3 »

Got the clutch today. Who delivers on a Saturday? Hopefully not long now
BMW’s
84 E24 M635csi
90 E34 M5 3.6
94 E34 540i/6 SC E85
97 E36 M3 euro SC U/C
97 Z3 2.8 widebody

OTHERS
11 Audi S5 3.0 SC
19 VW Amarok V6
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hornhospital
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Re: Driveline upgrade M635csi

Post by hornhospital »

GazM3 wrote: Sat Jun 27, 2020 9:25 amWho delivers on a Saturday?
Don't know about where you are, but here? USPS, UPS, FedEx, DHL, Prime.....
Ken Kanne
'84 633CSi "Sylvia"; '85 635CSi "Katja";'85 325e "Hazel Ann"; '95 M3 "Ashlyn"
GazM3
Posts: 1791
Joined: Wed Oct 26, 2011 12:55 pm
Location: Melbourne, Australia

Re: Driveline upgrade M635csi

Post by GazM3 »

Well got car back and after a few adjustments including proper phasing of the driveshaft to remove annoying hitting the body.

Firstly gearing feels much better. Nice to have a few legs in first and 2nd. The 3.23 combined with the dogleg seems to be a good combination. Rebuilt shocks feel great. The kMac adjustable bushes fit up well but the cups don’t have much overlap.

It’s going for a full alignment on Thursday morning so this will tell if I can dial out some of the negative camber at the rear. Aiming for around -1.5deg each side with around 1.5mm of toe in pet side. I’ll retain the -2deg at the front end and just a tiny bit of toe in say 0.3mm per side just to look after the inside edges.

Yes it’s been some time the 6 has had some loving. Probably 3 years. Been busy doing other cars so it’s hard to focus on 3 builds at once. The others are pretty well sorted so hopefully some more activity for the e24.

It really needs a standalone computer to get the best out of it. Being hearing abit of noise that ecu master have a plug and play m30 motronic 1.1 plug and play loom. Uses an e36 variable tps with wideband sensor, intake temp sensor and map sensor. It will be nice to have an adjustable ecu so it will allow easy upgrades when changes to the engine. I played with one of the 123ignition distributors and the dramatic change you can make to how a car drives with optimised ignition timing.
BMW’s
84 E24 M635csi
90 E34 M5 3.6
94 E34 540i/6 SC E85
97 E36 M3 euro SC U/C
97 Z3 2.8 widebody

OTHERS
11 Audi S5 3.0 SC
19 VW Amarok V6
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