Z4 6 speed gearbox in a Z3 -Help
Z4 6 speed gearbox in a Z3 -Help
I want to fit a 6 speed box in my 2.8 M52TU. I can buy a G6S-17 box from a Z4 that has a 2.5 N52 engine. Does anyone know if the gearbox bolts will line up with my M52TU? I realise there are other issues to sort, but the bolting up is fairly key.
You will have to make a template to be sure.
I've been told it will work, but you should be able to compare the two bell housings.
Please let me know how you get on.
I guess if you try roadfly or bimmerforums you might get an answer (it may take a very long time searching though).
Good luck!
I've been told it will work, but you should be able to compare the two bell housings.
Please let me know how you get on.
I guess if you try roadfly or bimmerforums you might get an answer (it may take a very long time searching though).
Good luck!
someone in a minority once wrote:I know I'm in a minority
Thanks -Okay I think I'll take the plunge and buy it. A couple of people have mailed me and said it will fit. Mpire from Bimmerforums has said that a bigger concern is getting it to physically fit in the tunnel.
If it does bolt up then I will also need to sort out what to do about the flywheel. The N52 only has 6 bolts onto the crankhsaft where as the M52TU has 8. If I use my existing flywheel I will need to make a new bearing housing for the splined input shaft as I believe Z4 gearbox has a shorter input shaft. I will also have to use the Z4 clutch as the splines are different, but the Z4 clutch is only 228mm and the Z3 has a 240mm clutch.
These are the issues I know -perhaps there other issues that I currently do not know.
If it does bolt up then I will also need to sort out what to do about the flywheel. The N52 only has 6 bolts onto the crankhsaft where as the M52TU has 8. If I use my existing flywheel I will need to make a new bearing housing for the splined input shaft as I believe Z4 gearbox has a shorter input shaft. I will also have to use the Z4 clutch as the splines are different, but the Z4 clutch is only 228mm and the Z3 has a 240mm clutch.
These are the issues I know -perhaps there other issues that I currently do not know.
This seems like an incredible amount of aggravation & expense. I'm not sure why one would want 6 gears on an engine with such a wide torque curve thanks to the Vanos. Added to the fact that fifth gear is tall enough as is. I've never felt the need for an overdrive on my ///M.
Perhaps there's something I'm missing here
Perhaps there's something I'm missing here
Last edited by Robin on Sun 17 Dec, 2006 20:43, edited 1 time in total.
'High G' motoring enthusiast
My friend bought an MR rather than an M3 for the very reason that the MR has the more functional 5 speed box rather than the frilly sales gimmick 6 speed box.
I admire your enthusiasm for an engineering challenge. Pressumably you've driven an M3 so you know what your in for having to faff around with a six speed box bolted to an engine that doesn't need it.
I admire your enthusiasm for an engineering challenge. Pressumably you've driven an M3 so you know what your in for having to faff around with a six speed box bolted to an engine that doesn't need it.
'High G' motoring enthusiast
I want 6 speed box because :
a) I like engineering and I want a new project.
b) I do find the engine a little high reving when driving on the motorway.
Looking at it objectively it is totally rediculous and pointless, but I just want to do it.
I am still keen to know if there are any other engineering issues that I am not aware of.
a) I like engineering and I want a new project.
b) I do find the engine a little high reving when driving on the motorway.
Looking at it objectively it is totally rediculous and pointless, but I just want to do it.
I am still keen to know if there are any other engineering issues that I am not aware of.
6 speed
I don't think you will have a problem. I put the M3 engine into the Z1 with no gearbox problems.
http://i81.photobucket.com/albums/j224/ ... 2f5aaf.jpg
viewtopic.php?t=8482
BUT! you must keep the flywheel and starter paired i.e you need the Z3 flywheel and starter or M3 flywheel and starter
I originally had the Z1 flywheel and M3 starter and that did not work.
You will also have to check the END diameter of the 1st motion shaft. If they are different then you need to change the bearing in the crankshaft (engine side). I think you will have a smaller bearing in the 2.8 compared to the M3. Bearing is about £1, but hard to get out.
http://i81.photobucket.com/albums/j224/ ... 2f5aaf.jpg
viewtopic.php?t=8482
BUT! you must keep the flywheel and starter paired i.e you need the Z3 flywheel and starter or M3 flywheel and starter
I originally had the Z1 flywheel and M3 starter and that did not work.
You will also have to check the END diameter of the 1st motion shaft. If they are different then you need to change the bearing in the crankshaft (engine side). I think you will have a smaller bearing in the 2.8 compared to the M3. Bearing is about £1, but hard to get out.
Engine Transplants by Night, Heart Transplants by Day. "you own the best Z1 in the world"
I've read that the 5-speed is supposed to be a better shift and less prone to problems. Either way I think a 6-speed would be better for this engine; it came with a 6-speed when it was released in the M3 EVO.Robin wrote:My friend bought an MR rather than an M3 for the very reason that the MR has the more functional 5 speed box rather than the frilly sales gimmick 6 speed box.
I admire your enthusiasm for an engineering challenge. Pressumably you've driven an M3 so you know what your in for having to faff around with a six speed box bolted to an engine that doesn't need it.
I find the gears a little long and drawn out (ie if you're doing 45ish or so dropping to 2nd is a little OTT but 3rd is 45-105mph), it would be nicer to have shorter intermediate gearing with a 6th thats slighter higher than the current 5th. It'd make the car more fun to drive IMO and feel more pokey too.
now that makes complete sense to me nowTimS wrote:I want 6 speed box because :
a) I like engineering and I want a new project.
b) I do find the engine a little high reving when driving on the motorway.
Looking at it objectively it is totally rediculous and pointless, but I just want to do it.
I am still keen to know if there are any other engineering issues that I am not aware of.
I have been diagnosed with ADHOTS. Attention Deficit Hyperactive Ohh That's Shiney
6 into 3 will go!
If anyone is interested .....The Z4 6 speed box will fit the Z3. You need to do a bit of engineering to make it happen, but it's fairly straight forward.
Gear changes and clutch operation are now much improved plus the engine is much lower revving on the motorways.
Gear changes and clutch operation are now much improved plus the engine is much lower revving on the motorways.
-
///M_aniac
- Z Register member
- Joined: Sat 30 Jul, 2005 19:34
- Posts: 4054
- Location: Belfast
TimS,
Why would you want to do this??
Why would you want to do this??
BMW Z3, the only way to build a true roadster
- The most powerful letter in the world.
- The most powerful letter in the world.Cloz wrote:There is something that will never change is my love for Z3
smartypants wrote:Conor?
With an M??
The World's gone mad
smartypants wrote:The Z3 rear is a great thing to behold
Here's a brief overview of what I did:
1) With the car on ramps I removed the exhaust, heat shield and driveshaft.
2) Made a cradle for my trolley jack to enable raising lowering of the gearboxes safely.
3) Unbolted the gearbox rear mount. You can then get at the splined bolts that hold the gearbox onto the engine. These bolts were a major pain to remove. I had to make a 3 foot extension for my socket set and then I had to hold the end of the wrench in place with a piece of wood wedged in the tunnel while I used my foot to push the wrench. I guess a real man would be strong enough to do it without this hassle.
4) Removed the old gearbox.
5) Removed the clutch.
6) Up to this point I planned on replacing the Z3 flywheel with the Z4 flywheel as the input shaft on the Z4 gearbox is shorter and the Z4 flywheel has the shaft bearing within it. However the new dual mass flywheels are not as well made as the one in my M52TU so instead I made a bearing housing adapter to take the Z4 shaft. To fit this bearing adapter you need to pull out the old bearing from the crankshaft.
7) Fitted a new clutch disk. The splines on the Z4 gearbox are different. I used a clutch from a 330i as its 240mm. The Z4 disk is only 228mm.
8) Fitted the new gearbox. I say new in fact it's secondhand -I had to repair it as it came from a smashed up Z4 but that's another essay in itself.
9) Made and fitted some adapters to take the new gearbox mounts. I spent a long time messing about here (2-3 hrs) to get the height right.
10) Cut down the Z4 control arm for the shifter (29mm)
11) Fitted the new shifter. - The Z4 shifter is real short - nice
12) Cut down the old driveshaft by 105mm. Had to make a steady for the lathe to do this. Again I spent a couple hours making sure I got the shaft tru before tacking and welding.
13) Fitted the driveshaft and heat shield.
14) Fitted the exhaust. This bit came as a surprise as it runs very close to the new gearbox mounts, but it doesn't seem to get too hot.
The whole job took around 2 weeks working Weekends and some evenings when I felt like it.
Why would I do this.....Well I like this type of thing and I am really pleased with the results. Gear shifting is much improved. The new ZF transmissions are certainly a lot slicker than the original one in my car.
1) With the car on ramps I removed the exhaust, heat shield and driveshaft.
2) Made a cradle for my trolley jack to enable raising lowering of the gearboxes safely.
3) Unbolted the gearbox rear mount. You can then get at the splined bolts that hold the gearbox onto the engine. These bolts were a major pain to remove. I had to make a 3 foot extension for my socket set and then I had to hold the end of the wrench in place with a piece of wood wedged in the tunnel while I used my foot to push the wrench. I guess a real man would be strong enough to do it without this hassle.
4) Removed the old gearbox.
5) Removed the clutch.
6) Up to this point I planned on replacing the Z3 flywheel with the Z4 flywheel as the input shaft on the Z4 gearbox is shorter and the Z4 flywheel has the shaft bearing within it. However the new dual mass flywheels are not as well made as the one in my M52TU so instead I made a bearing housing adapter to take the Z4 shaft. To fit this bearing adapter you need to pull out the old bearing from the crankshaft.
7) Fitted a new clutch disk. The splines on the Z4 gearbox are different. I used a clutch from a 330i as its 240mm. The Z4 disk is only 228mm.
8) Fitted the new gearbox. I say new in fact it's secondhand -I had to repair it as it came from a smashed up Z4 but that's another essay in itself.
9) Made and fitted some adapters to take the new gearbox mounts. I spent a long time messing about here (2-3 hrs) to get the height right.
10) Cut down the Z4 control arm for the shifter (29mm)
11) Fitted the new shifter. - The Z4 shifter is real short - nice
12) Cut down the old driveshaft by 105mm. Had to make a steady for the lathe to do this. Again I spent a couple hours making sure I got the shaft tru before tacking and welding.
13) Fitted the driveshaft and heat shield.
14) Fitted the exhaust. This bit came as a surprise as it runs very close to the new gearbox mounts, but it doesn't seem to get too hot.
The whole job took around 2 weeks working Weekends and some evenings when I felt like it.
Why would I do this.....Well I like this type of thing and I am really pleased with the results. Gear shifting is much improved. The new ZF transmissions are certainly a lot slicker than the original one in my car.
What about long term implications. I'm all for retrofits, but they have to be as good or better in the long run to be worthwhile, otherwise you are just openning up to a world of pain later.
Can you forsee any long term failure in the work Tim?
Can you forsee any long term failure in the work Tim?
1998 2.8 M52TU, pre-facelift, hard top, montreal blue, tan interior, 91K
