e21 speedo/odo and manual conversion

[Creaver 55]

Quick question on behalf of my mate who owns an e21 318i auto.

He is in the process of converting it to manual and found it very hard to aquire an e21 manual box. He currently has an e30 m10 getrag 240, but it doesn't have a speedo drive (like the e21 box's).

He has a few ideas on how to get a working speedo/odo. If I recall it was to get a diff from an e30 and wire up the electronic speedo to an e30 instrument cluster, but he is also wanting some advice from others.

Now, the questions:

- Are speedos/odo's a WOF requirement? (we know they note the km's on the odo, but does this affect anything else?)

- What ways would you suggest to get a working speedo?

Cheers,

Ian.

[CamB 48]

He is in the process of converting it to manual and found it very hard to aquire an e21 manual box. He currently has an e30 m10 getrag 240, but it doesn't have a speedo drive (like the e21 box's).

The diff idea might work, but would be hard as the back plates are different and the sensor mounts through the back. From having looked in there, but not tried, I'd guess the chopper ring from the E30 diff would fit (R&P is the same for e21 and e30 small case).

Alternatively, he could:

a) put in a 4 speed. I have one (or maybe 2) that would be cheap as chips. The problem with them would be finding the right length propshaft

b ) put in some sort of aftermarket speedo

c) I have the correct e21 5 speed and could be convinced to part with it for the right $$$. It has the speedo cable, and it whines a little). I don't really want to sell it coz it would mean I have to stuff around getting a speedo to work in my car

Edited June 3, 2008 by CamB

[Creaver 55]

Wouldn't swapping the chopper ring be sort of redundant as you'd need to switch backing plates anyway because you need a sensor? Also, how much would it take to get the manual off your hands? There's a couple of other issues like is it the narrow or wide bellhousing arrangement, and would a prop shaft suited to an e30 5 speed fit the e21 5 speed?

[Mark 178]

- Are speedos/odo's a WOF requirement? (we know they note the km's on the odo, but does this affect anything else?)

Yes.

[QuickSilver 0]

In regards to prop shaft, getting one thats too long cut and welded and balanced would also solve your problem, I understand its not to costly.

[kerrynzl 3]

Chuck the correct box in it.

All BMW 'Diff' speedo drive measures Axle speed [ thats why swapping ratio's don't alter speedo readings , but wheel sizes do ]

The Gearbox speedo drive measures Driveshaft speed , by the time this is all connected up and recalibrated you could have spent a bit more $$$ for the correct gearbox

[Five Star 0]

Putting in a dif from an e30 is possible, but not a simple job. e12 5 series dif is the way to go.

I'd suggest just putting in e21 parts, they can be found. It'll be far, far easier. Unless he's planning on running a lot of power??

[Creaver 55]

No performance, just wants a manual. The problem is that he doesn't want to go to a four speed, and e21 five speeds seem to be very hard to find. What makes this worse is the bellhousing bolts issue where two otherwise identical gearboxes have a different bolt pattern by one bolt and consequently won't fit on the engine. Likewise driveshafts are also hard to find. Any info pointing in the right direction would be great.

[CamB 48]

Wouldn't swapping the chopper ring be sort of redundant as you'd need to switch backing plates anyway because you need a sensor? Also, how much would it take to get the manual off your hands? There's a couple of other issues like is it the narrow or wide bellhousing arrangement, and would a prop shaft suited to an e30 5 speed fit the e21 5 speed?

The chopper ring would be very hard work.

The box is a 240 - it comes from an '83 e21. It is the same as the e30 318i but with a speedo drive. Based on my experience, it fits on an e30 M10 and on a 2002 M10 - I don't see why it wouldn't fit the e21 that it came from!

I don't know about the driveshaft, but the comment about cutting up a standard one is probably correct.

I'd want $400 PLUS your mate's e30 318i box, and that's for the box plus speedo cable plus old clutch/pressure plate, but nothing else (I need the throwout bearing, slave, and shift cradle). As I said, the box shifts well etc - the only issues are that it whines slightly and leaks a little from the speedo cable hole. I replaced the input and output seals.

[Five Star 0]

Do it once, do it right. I've got a 4 speed in my e21 320/6 and it's great. But give me the option of a 5 speed (sport maybe? ) and I'd probably take it.

I've seen 5 speeds offered on trademe recently from e21 wrecking cars. I'd have taken them if I had the time/money.

If you get stuck chuck a post on http://www.bmwe21.net/forum/ and hope for a reply. They know everything and anything when it comes to e21's, and you'll find write ups on changing dif's (to e30 and e12 5 series.. and everything else). I'm a bit rushed for study, otherwise I'd link you right there.

Just remember most e30 parts won't fit in an e21 without some modification.

[v8e21dreamer 0]

I have never heard of the bolt holes not lining up although I do know you need to get a custom driveshaft if your using anything other than the e21 5spd, even when swaping from a e21 4spd to a e21 5spd you need to swap in the drive shaft from the 5spd.

Try doing a searh in the e21 section at bimmerforums they are a great bunch of guys and anything you need to know will have been discused before so be shore o do a search before asking.

[CamB 48]

I have never heard of the bolt holes not lining up

Could be 4 cylinder vs 6 cylinder - then they wouldn't work.

Thinking about it, I have 2x 4spd Getrag 242 in reasonable condition (one whines slightly, one has a worn 2nd gear synchro), plus an old clutch, flywheel, pressure plate, throwout bearing, clutch slave and 2002 driveshaft (probably too short for an e21). All that's missing is crossmember and gear shift (I have the gear cradle etc too but it would need a new shift rod and gear lever as the ones I have are stuffed), plus something would need to be done with the driveshaft. I probably have the speedo cable too.

Do I need to talk to your mate about whether he'd be keen on this - it's a 4spd option and I'd be happy with $250 for the lot (no need to swap anything like I'd want for the 5spd).

[Creaver 55]

Thanks for all the replies. Have spoken to him, and he said he'd rather have a speedoless 5speed than a 4speed where he has to mess with the driveshafts (he has already measured up and bought some new driveshafts to fit the e30box).

He said he will put the box in and get it running etc and sort the speedo out later. Unfortunately he is not willing to spend/swap all that for your 5speed box as he has already bought 2 boxes/pedal box/driveshafts which fit etc.

If anyone has any more ideas for a speedo (which will work with the standard instrument cluster, as he wants to keep it original if possible, or perhaps swap the e30 instrument cluster in somehow) that would be great.

Thanks.

[CamB 48]

Thanks for all the replies. Have spoken to him, and he said he'd rather have a speedoless 5speed than a 4speed where he has to mess with the driveshafts (he has already measured up and bought some new driveshafts to fit the e30box).

He said he will put the box in and get it running etc and sort the speedo out later. Unfortunately he is not willing to spend/swap all that for your 5speed box as he has already bought 2 boxes/pedal box/driveshafts which fit etc.

If anyone has any more ideas for a speedo (which will work with the standard instrument cluster, as he wants to keep it original if possible, or perhaps swap the e30 instrument cluster in somehow) that would be great.

Thanks.

Cool - if he changes his mind let me know. My 5spd box is a straight swap size-wise to an E30 240 for an M10. The only difference between the E30 box and the E21 box is the end plate has a speedo drive.

I'd be happy with only $200 plus an E30 box if I knew the box I was swapping with was good (no leaks or crunches). There is no way he can get a working speedo for less than that (unless he is a fabrication wizard).

Edited June 5, 2008 by CamB