E30 Zone

Has anyone used a m10 gearbox on a m30 engine before? If so what was it like?

Thanks Rav

I've finished one conversion and I'm not far off finishing my 2nd with an M10 box.

Option 1
E30 M10 box
E30 320i prop
E30 320i gear linkage
M10 flywheel
M10 clutch
M30 starter

Option 2
Same as the above BUT
S14 M3 flywheel
M20 clutch

You have to use an uprated clutch for the M10 flywheel, I got a 5 puck paddle clutch from CG clutches for £250. I wasn't entirely sure it was up to the job but it worked.

I'm just about finishing my conversion with the S14 flywheel and M20 clutch which I have high hopes for. M20 clutch is a direct fit with the S14 flywheel, though an M20 flywheel physically bolts up it won't work as the ring gear is the wrong pitch for the M30 starter.

In actual use you won't notice that it's an M10 box, it just gets on with it. The flywheel is incredibly light though

Would love to do option 2 but finding a m3 flywheel is going to be a nightmare unless I buy one from bmw I should think.

Mine was £60 but was badly worn and has needed extensive skimming. As a disclaimer I haven't yet had option 2 running but the gearbox bolts up over the flywheel/clutch and the engine turns over freely with a socket on the crank bolt, I've read that it works too

For anyone that's interested, three flywheels: top left S14, top right E28 M30 M535i, bottom E30 M20


As above, here you can see the ring gear difference with the M20 flywheel


M30 with S14 flywheel and M20 paddle clutch

Rob, did you weigh your S14 Flywheel ?

I weighed an e34 535 DM Fly and it was 20kg!!!

The M10 fly must be about 10kg i would say so a hugh advantage

rob0r wrote:Thanks Rav

I've finished one conversion and I'm not far off finishing my 2nd with an M10 box.

Option 1
E30 M10 box
E30 320i prop
E30 320i gear linkage
M10 flywheel
M10 clutch
M30 starter

Option 2
Same as the above BUT
S14 M3 flywheel
M20 clutch

You have to use an uprated clutch for the M10 flywheel, I got a 5 puck paddle clutch from CG clutches for £250. I wasn't entirely sure it was up to the job but it worked.

I'm just about finishing my conversion with the S14 flywheel and M20 clutch which I have high hopes for. M20 clutch is a direct fit with the S14 flywheel, though an M20 flywheel physically bolts up it won't work as the ring gear is the wrong pitch for the M30 starter.

In actual use you won't notice that it's an M10 box, it just gets on with it. The flywheel is incredibly light though

Appologies for the thread hijack but this what I was searching for....

So what you saying robor is that this option will be best for my 320 cab?

just comparing it to the wiki parts list

M30 engine & gearbox
Custom engine mounts
E30 M20 rubber mounts
E30 325i exhaust
E30 M20 radiator in good condition (preferred choice is E28 535i rad)
E30 325i gear linkages
E30 325i manual prop
E30 325i gearbox flange
E30 M20 matrix hose (or E28 T piece)
E34 throttle cable
Electric fan

i have a possible m30 and m10 box lined up for a good price as my budget is anorexic to say the least...

The above list will work fine but i would get the burton power engine mounts and definitely the e28 535 radiator. Do use the m20 coolant tank hose rather than the t piece.

You really need an uprated M10 clutch if you use an M10 flywheel (M30 doesn't fit apparently), so your anorexic budget would need to swallow at least £250 for that. Swap out the bits in my list compared to the wiki list and you'll be golden.

For what it's worth, I've used Burton mounts a few times now and the last set fell apart within 30 mins of track driving (with a lighter M20!). Seriously unimpressed, the imbedded metal plates sunk into the rubber are too shallow IMO. I use hockey pucks and don't notice any ill affects, but most don't like this idea.

How much abuse will the m10 box and clutch take, not that I`m taking the cab drifting but for the occassional spirited drive and odd trackday ? Just trying to guage whether or not to go m30 box route as wont make much sense having to be replacing clutch quite often @ £250 a pop, whereas m30 b0x and clutch will have longer periods of use before replacing

If you don't find it any easier to go M10 then I would go M30 every time for ease of clutch sourcing and knowing the clutch will hold the power. I've only gone M10 a few times due to availability of the boxes (I have several) and the fact both of my cars have been 320i manuals, meaning the prop and gear linkage is already correct.

I believe the M10 box will take as much power as you could ever throw at it. In my latest conversion I'm using a solid centre paddle clutch and the car will primarily used for drifting, I don't anticipate any problems.

rob0r wrote:If you don't find it any easier to go M10 then I would go M30 every time for ease of clutch sourcing and knowing the clutch will hold the power. I've only gone M10 a few times due to availability of the boxes (I have several) and the fact both of my cars have been 320i manuals, meaning the prop and gear linkage is already correct.

I believe the M10 box will take as much power as you could ever throw at it. In my latest conversion I'm using a solid centre paddle clutch and the car will primarily used for drifting, I don't anticipate any problems.

Sounds like a beast....be sure to post a vid or two when doing what you do!

Im running a M10 box with STD M10 clutch I give the thing HEAPS !! Every day driving and spirited driving the clutch has no problems it's just when I give it all it's got it slips
I'm going to get a new std M10 pressure plate updated
As for the box they take a beating