Help! E21 M30B35 Conversion

[dtm]

Heya everyone, just wondering if anyone has done the M30B35 conversion in an E21 and give me some help??

Mid next week I am picking up my first Euro car it's a 1980 E21 which was originally a 320 6 cyclinder manual. When I pick it up it will have a M30B35 engine already in the engine bay which was originally from a 1987 E32 735i. The engine will be bolted in and basically all I have left to do in terms of the engine bay is wire it up and work out the fuel system. The engine also needs bolting up to a gearbox as the car currently does not have one. So here come my questions:

1) As far as im aware the 1980 E21 320i 6 cyclinder originally had a carburettor setup whereas the 1987 E32 735i was fuel injected, yes? Now I want to keep the remainder of the work on this car as cheap as possible so I want to keep the car carburetted in the meantime and further down the track when funds permit I will convert it to fuel injection. So what sort of carburretor set up should I look at?

2) The E21 was originally a manual car, not sure whether the E32 was or not, and I wish to keep the E21 as manual. I hate automatics! What gearbox would I be looking at bolting into the car??

3) Finally where is the best place to locate the gearbox and carburettor gear I will need to finish of this car? Im located in Adelaide.

I had a quick search to try to find some answers to these questions but couldnt find anything hence why Im asking.

Im really excited about picking up this E21 next week as Ive always loved the early 3 series and have been after one for quite a while now. The one Ive found has a good body and retrimmed interior and comes with lots of parts and Im getting it at a very reasonable price too. I want to find out what I have to do to finish of the car so that I can hopefully pick up some parts for it over the weekend as I will need to get it running a.s.a.p as it will be daily driver.

Any help is greatly appreciated

[Stoney]

Dont even consider a carby setup on the motor, it will cost more than setting up a proper efi system? as you will require a custom inlet, and triple 45mm webers (its the only way you would go with a carby setup)

modifying the original fuel tank to accomodate an EFI pump, sender, and cradle would be the best solution, just source a setup from some small car that has a metal fuel tank the same depth as yours, basically cut around the fuel pump opening, and weld that onto your tank, whilst setting the pickup in the right place, maybe even add some baffles to help prevent fuel surge (welding obviously once the tank has been washed internally with soapy water)

Sorry to say, but the hardest part of this conversion will be the wiring, i'd work out what you do and dont want, like A/C, power steering, etc and modify the engine/ECU loom to its bare essentials, and keep it as seperate as possible from the body loom

[dtm]

ok so EFI it is then. in terms of what i want to keep, as its a light car (around the 1000kg mark) im not bothered about keeping the power steering but i do want to keep A/C. ill be getting an auto electrician to wire it up for me though, how much is this going to set me back? what should i do about the gearbox set up? can i use an e21 320 gearbox from another car or will this not bolt up to the m30b35 motor?

[matt_dumesny]

Dont even consider a carby setup on the motor, it will cost more than setting up a proper efi system? as you will require a custom inlet, and triple 45mm webers (its the only way you would go with a carby setup)

modifying the original fuel tank to accomodate an EFI pump, sender, and cradle would be the best solution, just source a setup from some small car that has a metal fuel tank the same depth as yours, basically cut around the fuel pump opening, and weld that onto your tank, whilst setting the pickup in the right place, maybe even add some baffles to help prevent fuel surge (welding obviously once the tank has been washed internally with soapy water)

Sorry to say, but the hardest part of this conversion will be the wiring, i'd work out what you do and dont want, like A/C, power steering, etc and modify the engine/ECU loom to its bare essentials, and keep it as seperate as possible from the body loom

We've ran them with 350 Holleys and have a stack of twin carb manifolds - we have a twin carb M30 engine with auto trans sitting beside the shed at the moment.

[dtm]

We've ran them with 350 Holleys and have a stack of twin carb manifolds - we have a twin carb M30 engine with auto trans sitting beside the shed at the moment.

would you be willing to sell the twin carb set up? =)

[Gruelius]

my 5c is that if you are capable at auto wiring yourself i would just go straight to fuel injection by a stock system. there are assloads of m30's at local wreckers so you wouldnt be set back much more than a set of good carbies for the manifold injectors ecu and loom.

[Varden]

Gudday dtm, I'm also a fan of the e21 but I opted for the somewhat easier M20B25 conversion.

The M30 motor is easy to find as they last forever and as a consequence they are plentiful in euro wrecking yards and in beaters with crapped out auto boxes.

BUT

You'll be needing the box from a e28 528i or any 5spd to fit the M30 big six engine from the e28-e34 range.

Problem is they are somewhat sought after and hard to get your hands on, I saw a complete e28 5spd manual conversion kit sell recently on fleabay for just under $1k.

And correct me if I'm wrong folks but the manual box will need to be the same vintage as the efi as i think there is a reference sensor in the bellhousing.

Best bet is to keep your eyes open for a shit box e28 M30 6cyl with a 5spd, theres a car up here right now for $1400 that would make a great donor.

You could use a 318i box from the e21 but I dunno how long it would last before you killed it.

Or you could mate an M30 auto bellhousing to a supra box with a custom tailshaft, but I'm just speculating about that as an option as I've never heard it done.

As for the electric pump for the efi, a 323i e21 tank will have an intank pump and if its not supporting the e21 kjet you *may* just get away with the one pump to run your efi but I'd look at putting on an external pump too.

As for more answers look here ---------> http://www.bmwe21.net/forum/

And if you come to your senses there is an M20B25 on ebay here -------------> http://cgi.ebay.com.au/ws/eBayISAPI....=STRK:MEWAX:IT

[Gruelius]

varden may be on the money, i got told a e21 is quite hard to drive on the edge

[dtm]

yeah the m20b25 would probably be easier but im picking up an E21 with completely retrimmed leather interior, good body, a heap of spare parts, the m30b35 already in the engine bay for about $3k. ive just gotta sort out the wiring, fuel system and the gearbox... and do it all asap on a very limited budget as it will be daily car

[Varden]

When you say "Already in the engine bay." do you mean, custom engine mounts, custom radiator mounts, custom radiator, custom exhaust and correct sump etc already fabricated and ready for a 5spd box?

Or do you mean the engine is sitting in there and i just have to figure out how to make the engine mounts, what radiator to use and how to fit it into the e21 engine bay with the M30?

[dtm]

When you say "Already in the engine bay." do you mean, custom engine mounts, custom radiator mounts, custom radiator, custom exhaust and correct sump etc already fabricated and ready for a 5spd box?

Or do you mean the engine is sitting in there and i just have to figure out how to make the engine mounts, what radiator to use and how to fit it into the e21 engine bay with the M30?

the guy im buying it off said that he would drop the motor into the bay for me and sort it all out and he said all i would have left to do to get it running and driveable is to wire up the loom, wire up the efi and locate and install a gearbox...

i had a good search around for information on the gearbox and the best thing i could find was to use the gearbox from a 528i e28 and then wreck the rest of the car out for parts. the cheapest one i can find in adelaide is $1500 and i dont have that sort of money lying around. its now looking unlike i will be buying this car from him as i will have to get a loan out to finish it and thats something i dont want to do.

he has also got an e30 rolling shell hes happy to sell me on the cheap so i may just buy that and leave it undercover in my driveaway until the uni holidays in november when i have time to do some sort of engine conversion to it.

[Gruelius]

just take the e21 without the m30 for $500 less, then pick up a written off e34 for $500.

Either route you go there is no way you will have it done in a week, but the m20 path is much more manageable.

[Varden]

if you've got your heart set on a 3 series, i'd be picking up a e30 318i 2dr if i were you, you should find one of those regd and RWC for $3k.

You get your daily and there is much scope for future mods (M20B25), oh and M10 engines last forever too.

[dtm]

yeah im really keen for a 3 series. i love E21s and E30s a great deal and will probably end up getting an E30 now as they are easier to find and locate parts for. ive decided i will buy his E30 rolling shell which is complete minus engine and gearbox which i can get for $400. ill keep it covered on my driveway and continue using my current commodore as my daily. then in 2 months time when uni is over and i have more free time and less of a need for a car i can sell the commodore for about $3000 which i can then plow into the E30.

Ill either *puts on flame suit* drop a 13bt engine and gearbox into as i am a big rotor fan or i will perhaps go with a m20b25 or something similar bmw wise. Ive got a couple of months to look into either route. the main aspects i will be looking at is: cost for the conversion, reliability, modification potential, future costs in terms of maintenance and modifications and how each engine will affect the car in terms of handling.

i think the two engine choices are relatively evenly matched. the bmw motor would be cheaper and easier. the rotor would have a greater modification potential and would be nice and light in the car giving better handling than a big i6. both would be roughly matched in terms of reliability and maintenance costs. rotors can be reliable if set up right.