m46 to m90 conversion questions..

[NeoSpeed740ti]

My gearbox is dying (m46) but unlike so many other m46's I've heard about grenading, this one just grinds and shifts like a garbage truck and pops out of gear. :( Not sporty at all. So this brings to the topic of m90 conversions, cuz I'm not about to throw in another m46 and have the same headache later. I already know what I want (m90L or L2) I want to have the shorter (more usable) top gear.

After doing some searches I still was unable to figure this one out. Can the crossmember for the m46/47 be used with the m90 tranny in place of the m90 crossmember? As far as the rest goes I've come to the conclusion all I need is the m90 and the front half of the drive shaft, It should work with the stepped flywheel that was stock on the turbo m46 cars with maybe some gear chatter due to the shorter input shaft not riding inside the pilot bearing, right? I'm just trying to sort this out so I know exactly what I need when I do an m90 conversion. I think I should be able to get one from the UK, but if anyone has an m90 they want to sell and wouldnt mind shipping it to Oceanside, CA I'll buy it right now. pEACE.

-Joe

[Chigga 744SE]

hey man, this is just something to think about.

about few months ago I decided to do a proper tranny swap. I was stuck between a Getrag 265 and a M90. Both works out to be equal amount, and Getrag might be even more, but at the end, ask yourself a question. If the M90 goes, can you find a replacement in a week?? of course if you have storage place, then getting two trannies at once is ideal. But I don't, I live in a condo.

so at the end I chose Getrag 265 cause its hella easier to get parts or entire tranny, and it holds slightly more power.

[Wagner]

What car you going to put the m90 in?

If you have a 200-series car, then a readily available drive shaft does not exist.

If your car does not have a hydraulic clutch then you need a master cylinder and a slave cylinder too for the clutch fork (and the original m90 clutch fork naturally). Now it is possible to convert the m90 to cable operated clutch fork, but going the hydraulic way is easier, at least i found it to be so. You can use 700 and 900-series parts (even some 200-series cars had the hyd. clucth fork operating system).

If you have a cable driven speedometer you're going to have to convert to an electrical speedometer as the m90 does not have a speedo cable output. This is no biggie, you need a rear axle from a car with an electrical speedo (or the carrier from such) and the speedometer itself.

Some Volvo 800-series diesel clutch disc fits the m90 main shaft and is 228mm in diameter. That is the size of the clutch plate when using a stepped flywheel. That might be the easiest solution, though there might be some pressure plate/clutch disc fitment issues. I'm not sure of that. I used a BMW 228mm sport pressure plate (i used the same pp with the getrag project) and a custom sintered clutch disc with the flat flywheel. They do not fit directly, so the flywheel has to be modified to accommodate the BMW pressure plate.

The crossmember has to modified also if putting the m90 to a 200-series car.

If you're planning to use the m90, you might wanna do the welding/strenghteting modification to it before installing it to your car. The instructions for that can be found in a Bilsport article, which has been translated to English on this site. Search is your friend.

[NeoSpeed740ti]

It's going into a 740 with a hydraulic clutch. Does the 740 m46 crossmember work with an m90 or do I need the crossmember for the m90? As far as parts are concerned If I break something I can take the guts out of an 850 manual tranny and swap them in. Thanks for the tip on the weld trick for the 3rd gear I remeber reading something about that a while ago. As far as going the getrag route, I don't think the getrag is any stronger then the m90, and I like the idea of using a volvo tranny, jesus puts an ungoldy amount of power through his m90. Thanks for the tips.
-Joe
----------------------------------
'98 b230ft, megasquirt, t4/t3 hybrid, npr intercooler etc. .......and a sh*tty gearbox :(

[Wagner]

What i don't like about the m90 is that it leaves the main shaft kind of "floating" in the air. It does not reach to the pilot bearing, unless you do some sort of really odd looking "holder/extesion/thingamagic" for it.

It is a strong tranny compared to the m46, but i have seen broken main shafts on the m90s too. You do need a lot of torque for that to happen though.

And the Swedes are driving 11s on the 1/4 mile strip with those trannies. They are good for something.

[Captain Bondo]

Originally Posted by Wagner

What i don't like about the m90 is that it leaves the main shaft kind of "floating" in the air. It does not reach to the pilot bearing, unless you do some sort of really odd looking "holder/extesion/thingamagic" for it.

I had been worried about that, but when doing a clutch on an M56 I discovered it is the same way in the FWD, and people are putting TONS of power through the M56.
The M56 input shaft doesn't even have a little pilot section on the end of the shaft, it just kind-of ends.
Seems weird but that's how they are stock, which makes me feel less concerned about it.

[Wagner]

So I found some pictures of the main shaft situation:

here's how it's on the M-46 (and getrag also)



Here's how it's on the m-90



As you can see the main shaft is too short for it to reach the pilot bearing if one does not make some sort of silly looking adaptor/holder/thingy for it. But as Capatin Bondo stated, that's the way they are stock, the main shaft just hanging out in the open air. And people do put alot through these trannies.

Originally in the 900-series, where these trannies come from, they are coupled with a dual mass flywheel. I've never seen one myself. It was suggested to me, that volvo had the pilot bearing in the flywheel when using the dual mass flywheel and therefore the main shaft would be long enough. I do not know whether it is so or not. I doubt it though.

And now that Cap Bondo told us that there is no pilot bearing on 800-series, it makes me doubt the "pilot bearing in the dual mass flywheel" thing even more.

But that's just me rambling. It has been done before in such a way that the main shaft is left hanging in the air and it has been fine. It is hanging in the air in my setup too and it has been fine. It just does seem a bit, umm, silly.

But here's a picture of the 900-series to M90 crossmember. I don't know if it does or does not fit directly to a 700-series car.





The distance from the middle of the hole A to hole B is approximately 1 inch

The distance from the middle of the hole B to hole C is approximately 3.1 inches

The distance from C to D is approximately 16 inches

[CHESH740R]

Originally Posted by Wagner

But here's a picture of the 900-series to M90 crossmember. I don't know if it does or does not fit directly to a 700-series car.

hope this answers your question.

http://forums.turbobricks.com/showthread.php?t=32626

[BB-Q]

While we're on the subject of M90's, it seems daft not to change the oil on mine while it's still sat on the garage floor. Does anyone have a definitive answer on what oil it should take? Some say synthetic ATF and some say ep80/90.

[CHESH740R]

Couldnt tell ya, the volvo part number is 1161645 and you need 2 of these litre bottles.

Can't rememeber the price to be honest, and the bottle doesnt have any tech specs on it, apart from its good down to -48C

The Volvo oil is absolutely the best.

We tried another "super oil" in my dads M90 when it passed 125k.
It got changed again at 150k to Volvo oil.
It got kinda rough in the winter with the old oil.

[Julio]

Maybe the same Volvo oil used in the M56 stateside can be used in the M90?

[CHESH740R]

Originally Posted by Julio

Maybe the same Volvo oil in used in the M56 stateside can be used in the M90?

The bottle states M56 transmissions as well so i would expect so.

[Julio]

Originally Posted by CHESH740R

The bottle states M56 transmissions as well so i would expect so.

Xcellent! Thanks Chesh. Now I know what to buy.

[HRPufNStuf]

Volvo pocket data book(TP 0302207) lists:

M90H/L
synthetic oil p/n -11 61 423 oil capacity 1.75L

M56L/M56L2/M56H/M58/M59/M58L/M58L2
synthetic oil 5W30 p/n -11 61 423 oil capacity 2.1L

Originally Posted by Julio

Xcellent! Thanks Chesh. Now I know what to buy.

[NChoy]

Originally Posted by Bertiebandit

While we're on the subject of M90's, it seems daft not to change the oil on mine while it's still sat on the garage floor. Does anyone have a definitive answer on what oil it should take? Some say synthetic ATF and some say ep80/90.

I'm using Redline Synthetic in mine. Good oil, no chatter, smooth shifting...

[foggyjames]

Just don't ask me to ship you one - three and counting waiting to go out

Good luck with the project, it's an awesome gearbox.

cheers

James

[BB-Q]

Just done some research on the clutch and can confirm that the 2.4TD clutch is identical to the M46 clutch with the exception of the release bearing on the later models (by identical I mean the the pressure plate and release bearing on the earlier models and the pressure plate on the later ones. Obviously the friction plate os different or it wouldn't fit the input shaft!).

If you know the year of the M90 you have then you can just buy the appropriate clutch kit. The later ones, though are quite a bit dearer, and the only difference is the release bearing. If you're on a mega- tight budget then get the earlier clutch kit and use the M46 release arm in he M90 box.

[leomartin6]

In order to improve the performance, this sort of conversion is necessary. i am also planning to convert mine too.

[MadDog_945]

Its just that simple


If you have M46 youll need

- M90 ;)

- Kardan shaft from M90

- M46 Pressure plate for TurboDiesel with M90 >95 Sachs No°3082 204 033
(or Sachs performance No° 883082 999763)

- M46 Clutch No° 1861 905 039 (or performance 881864 999996)

- Shift Lever with all stuff and boltsnnutsnstuff and so on ;) - M90 4sure ;)

- Gearbox Mountingbridge M90

Thats all you need



AND ! Yep.. the pilot bearing you can throw away.. gearboxshaft will be too short to fit..

AND N°2 The M90 is a quite cool gearbox.. shifting is like in a sportscar :D

[foggyjames]

Originally Posted by MadDog_945

- Gearbox Mountingbridge M90

This part (crossmember) is the same as for an M46 in a 7/900. What you will need is the bracket which bolts onto the gearbox. Sometimes this (four bolts) is removed, instead of the one bolt from the mount to the bracket...strange!

cheers

James

[Janspeed]

Originally Posted by MadDog_945

Its just that simple


If you have M46 youll need

- M90 ;)

- Kardan shaft from M90

- M46 Pressure plate for TurboDiesel with M90 >95 Sachs No°3082 204 033
(or Sachs performance No° 883082 999763)

- M46 Clutch No° 1861 905 039 (or performance 881864 999996)

- Shift Lever with all stuff and boltsnnutsnstuff and so on ;) - M90 4sure ;)

- Gearbox Mountingbridge M90

Thats all you need



AND ! Yep.. the pilot bearing you can throw away.. gearboxshaft will be too short to fit..

AND N°2 The M90 is a quite cool gearbox.. shifting is like in a sportscar :D

AND a clutch release bearing from a '95-'98 M90-940LPT
If you use the clutch release bearing of the M46 it will rattle

AND a pivot bolt of the M46 (= slightly longer then the original M90 pivotbolt, the longer one is needed to compensate for the lesser distance from crank mountingface to flywheel frictionface when using a solid dogdish flywheel in stead of the dual-mass flywheel to which the M90 was matched from the factory.)

[tree18is]

why not go T-5? you wanna keep it volvo thru and thru?

[arsenix]

hm... i just can't decide which face palm image to link. So many to choose from.

[MadDog_945]

Originally Posted by foggyjames

This part (crossmember) is the same as for an M46 in a 7/900. What you will need is the bracket which bolts onto the gearbox. Sometimes this (four bolts) is removed, instead of the one bolt from the mount to the bracket...strange!

cheers

James

Maybe cause the Screw from the Gearbox rubberbearing is a little bit too deep in that bracket.. so you cant see it.. i dont know.. but youre right ;)

But thought the release bearings were the same @ m46, m90... ??