All you need to know about the M90

[ThunderCougarFalconBird]

Hi TB!

I just installed an M90 in my 1993 945T and I can't get the clutch to disengage. What's the best way to adjust the engagement point of the clutch?

In 1st gear with the rear end off the ground, the wheels spin the same even if the clutch pedal is fully depressed.

The clutch setup is off another TBer's 945T, with a flat flywheel, 850 clutch disc, and a pressure plate - though I couldn't say which one (I imagine it came with the flat flywheel). Since its last installation, the clutch disc was replaced (damaged in shipping) and the flywheel was refaced.

The clutch fork sticks out of the bellhousing perpendicular to the input shaft, and the pivot ball is already spaced on 4 washers. The slave cylinder rod is ~4 inches long. With the slave installed, the throwout bearing rests against the pressure plate. With the clutch pedal fully depressed, the slave moves the clutch fork ~1cm.

The hydraulic system was bled by pressing the pedal & bleeding the slave. I tried a reverse pressure bleed but it didn't go anywhere.

The master cylinder rod that attaches to the clutch pedal will spin, but that doesn't appear to adjust the rod length.

Where should I start adjusting? I can post a video of the clutch actuating if it would help with diagnosis!

Thank you!

[ZVOLV]

I would really really really bleed the clutch. I did a Mini Cooper transmission recently and it called for a special tool to compress the slave cylinder during bleeding and I was, like, " I don't need that ****!" And I was wrong. Couldn't get the cclutch to relase. Wouldn't even go into gear. I made a special tool, rebleed, and got it to work.


I doubt you could even smash a dog dish pressure plate against a flat wheel, but maybe.

Plate could also have bent or worn fingers. A fresh one should have been installed.


I forget exact spec for clutch pedal throw, but 1 cm may not be enough.

[Mule]

Just wondering if I can pick your collective brains?

So, I'm building a 240 with a T6 and whiteblock M90.

What would the best clutch set up be for 370-400bhp and 460ishNm?

850t5 240mm solid flywheel with shorter bolts.
850r clutch and a either a 850r pressure plate or Sachs 707 (is this a direct bolt on fit?).
Maintain the original external slave cylinder, fork and bearing or go to a concentric slave?

Is there a better set-up that doesn't cost the earth?

Any recommendations for UK suppliers?

I'm waiting to hear back from TTV.

Cheers for your help.

[Chris Wilson]

Originally Posted by Mule

Just wondering if I can pick your collective brains?

So, I'm building a 240 with a T6 and whiteblock M90.

What would the best clutch set up be for 370-400bhp and 460ishNm?

850t5 240mm solid flywheel with shorter bolts.
850r clutch and a either a 850r pressure plate or Sachs 707 (is this a direct bolt on fit?).
Maintain the original external slave cylinder, fork and bearing or go to a concentric slave?

Is there a better set-up that doesn't cost the earth?

Any recommendations for UK suppliers?

I'm waiting to hear back from TTV.

Cheers for your help.

Tilton or Quarter Master concentric release for sure, forks are like carburettors, history. Much better pedal feel, effort and reliability. Avoid ceramettalic clutch plates for a road driven car if you can find an organic plate and cover to handle the torque. Use a sprung centre plate. On a budget look at using a Saab or Ford concentric release, but you may spend the savings getting stuff made to fit them onto the bellhousing unless you have machining facilities FOC.

[Mule]

Originally Posted by Chris Wilson

Tilton or Quarter Master concentric release for sure, forks are like carburettors, history. Much better pedal feel, effort and reliability. Avoid ceramettalic clutch plates for a road driven car if you can find an organic plate and cover to handle the torque. Use a sprung centre plate. On a budget look at using a Saab or Ford concentric release, but you may spend the savings getting stuff made to fit them onto the bellhousing unless you have machining facilities FOC.

Cheers for the information.

Concentric master cylinder it is then. I'll have a look at the ones you recommend but maybe I can go Volvo 850?

Just thought I would clarify. I don't mind the prices of Volvo and Sachs new, so don't mind spending a few £££. I'm not in the position to spend on a custom clutch I don't think.

I think the 850R organic plate will be fine. It's more the pressure plate really and what's best.

[pujdeme_domu]

Hi guys, can somebody ensure me, the gearbox on picture

http://www.prestolholding.cz/admin/u...2fdd4b8013.jpg

is M90 whiteblock?

Thanks a lot

[V945]

Hi! Where on M90 I can find identification plate? I found number 6942485 on back side, it enough for detect modification M90?

[classicswede]

Originally Posted by pujdeme_domu

Hi guys, can somebody ensure me, the gearbox on picture

http://www.prestolholding.cz/admin/u...2fdd4b8013.jpg

is M90 whiteblock?

Thanks a lot

No it is not a whiteblock M90

[classicswede]

Originally Posted by V945

Hi! Where on M90 I can find identification plate? I found number 6942485 on back side, it enough for detect modification M90?

If still there it is a white label

[pujdeme_domu]

Originally Posted by classicswede

No it is not a whiteblock M90

Interesting is, that it fits B5234T3, the number is 1023650-8, I cannot find it anywhere, looks different than any other M90 marking

[themidnightgarage]

I am planning to put a M90 on my 1994 940 b200ft.
can i use the pressure plate from the m46 setup with a TDI clutch?
It has the same specs as far as i can see but im not sure.
Is there a difference between the m46 and the TDI pressure plate?
both are 228mm

[MadDog_945]

oh.. my.. god.. i opened it... this... is.. a mess :D

does anyone have plans of the m90? ;) This is the first time i opened something and fearing not being able to put it together again :D

[petiww]

Good pics, keep them coming!

I'm curious about the bearing sizes, i hope they are not some special 'only for m90 only' ones. Getting the preload right with new bearings is going to be pita though, more likely because I don't even know if the factory specs exist in any greenbook.

[MadDog_945]

Originally Posted by petiww

Good pics, keep them coming!

I'm curious about the bearing sizes, i hope they are not some special 'only for m90 only' ones. Getting the preload right with new bearings is going to be pita though, more likely because I don't even know if the factory specs exist in any greenbook.

thats the reason i opened that ****er up.. i want to know whether all the bearings are replaceable.. seems that koyo and skf is all over the place.. havent found a different manufacturer till now

[RolinOldies]

So i got myself this M90 gearbox to install in my Amazon Combi B230 Turbo.
I am now running a M46, it is still holding up with the 227HP/373nm but i don't want to wait for d-day and prepair a stronger unit. Ofcorse more tunnel work and other mods will have to be done.

My guess was it was a M90L2.
Turing the input and count the revs in versus out, first and second gear confirmed it is indeed a L Type (L1 or L2).
Then doing the same on fifth gear to know if it is the L1 or the L2.
BUT... to my surprise it matches neither one of those

The L1 type has a 5 ratio of 0.81 to 1 and the L2 type 0.7 to one.

Mine has a 0.7525 to one ratio!

I googled about an hour to find other gearing types for the box but ALL showed the same, know as 0.81 and 0.7 5th gear.
I learned the internals *might* be interchangable between FWD M56/M66 and M90 boxes, so i looked that too (maybe someone switched the gearing on 5), but also for these boxes no 0.7525 or anything near that seem to exist.

I'm sure i did the correct measuring:
I first turned the input shaft until the out made a full turn. The in made about just 3/4 of a turn, just a tad more.
To find out how much exactly, i then turned until the out made 4 turns. The in made then 3 turns and a bigger tad.
So then i turned until the out made 16 turns, the in made 12 and about 14° extra.
Then i made 12 times 12 turns (on input) and found that the mark i made on input then almost made 1/2 turn extra to align the out on it's mark.
So i turned input again 12 times 12 turns (now total 24 x 12) and fount i needed to turn it once more 12 turns to get the input mark straight up (360 degrees) again.
Margin of error reading marks is very small now the input shaft turned 301 times, so the fault is devided by that! 2x(12x12), +12 (+1 the mark turned 360° extra)
while the out made 25 x 16 = 400 turns. 301/400 = 0.7525 gear ratio.

Now i suspect ALL documentation is WRONG about the L2 being 0.7 in 5
Did anyone alread did the math turning and counting, or did anyone already OPEN THE BOX AND COUNT THE TEETH ON FIFTH GEAR GEARS?

or do i just have an exotic and spooky M90

[RolinOldies]

Two days ago i bought myself another M90, this time a H1 type.
I did the test on all gears by turning and all are just like in the spec's.
Next step will be opening the L2 box, since no one seem te have done this to count the teeth on 5th...
I re-tested and re-calculated over and over, still come to 0.7525 / 1 or 270.9 degrees on the in for a full turn on out.

[RolinOldies]

Originally Posted by MadDog_945

oh.. my.. god.. i opened it... this... is.. a mess :D

Hi MadDog, did you put yours back together? and do you know what type it is?
I also opened my L2 to check 5th gear and i was right!,
drive gear is 46 teeth, driven gear is 30 teeht so 0.652174 ratio multiplied by the end ratio from secundary axle to outgoing axle (26 to 30 teeth) 1.153846 makes 0.7525084
SO ALL DOCUMENTATION IS WRONG!!!, or i have a special one

on this image of you the 5th is (for an L2) 30 teeth on the right axle top gear, and 46 teeth on the middle axle top gear (left axle is upside down in your pic but not important for 5th)



I didn't get the outgoing axle out of the housing tail, did you press it or just hammer?
Is that middle part some removable bushing?


Now i want to also open my H1 to check if i can swap first gear into the L2
Anyone ever tried this?

[MadDog_945]

mh.. sry long time ago.. i can remember i struggled hard on this one.. i had a guy helping me keeping the 2 shafts out of the way then just pull like a retard and it popped out..

[RolinOldies]

Ok, i'll get it off somehow
Here is an image i found on the web i added some extra info and translate to another unspeakable langue .

Also found that third gear is NOT 1.38 but 1.35, could be 1.38 if gear 16 had 42 teeth instead 41, i think someone miscount making the info, i count it at least 5 times
and Reverse is NOT 3.00 but 3.80, chequed also by turning, but who cares about reverse

Here's the ratios i calculated on my L2 box:
1st: 3.9053254
2nd: 2.1978022
3th: 1.3516484
4th: 1
5th: 0.7525084
R: 3.8051889

Based on the number of teeth in the pic you can do the math.
After (if) i open my H1 box i'll post results here too.
cheers!

[volvo78244]

Does anyone have the pictures of the gearbox parts in the first post?

Just picked up another M90L2 and need some parts replaced.
Don't want to bother the dealer with all my questions about stuff they don't know.

Thanks.

[kittysgreyvolvo]

On a facebook article:

https://www.facebook.com/groups/2376...9103561083561/

Someone selling an M90 in Indiana.



Volvo M90 Gearbox Volvo PN 1023650-8

Post here to show this part number exists in the Volvo M90 all I want and need to know, verily!

[usuniety]

Hi, does anyone maybe have pictures from the first post of this topic?