bmwe21.net forums

ok been trying to decide for a while what donor car to buy to swap into my e21, originally wanted a 320/330/530d with 6 spd manual box but cost of donor and the hassle with the electronics has put me off

considering a m51 conversion from a 325tds/e34 525tds

is there much involved, would i need mounts made up and would there be much wiring?

done a search but not much there

The question is why do you want to put Diesel engine in your E21? IMHO Diesel just doesn't go with classic, sexy appeal of E21.

because its the only way i can drive it all day every day as i drive up to 1000 miles per week and cannot afford to do this in a petrol car

do it it wont be long before someone does it why not be the first. IMO its an awesome idea 123d engine in e21 would be hilarious.

oh im doing it ive been quoted 600euro for the conversion and can get the donor for £500 but want to know is there much to it that i could manage it myself as im very much hands on and prefer the built not bought kind of car

what a car it would be e21 330d turbo 6 speed do it go on do it you know you want to

harleytrike wrote:what a car it would be e21 330d turbo 6 speed do it go on do it you know you want to

i do i do but prefacelift 5 spd is 1500 car then 1500 for conversion and ecu needs flashed and all other nonsense for 190bhp

tune the 143bhp m51 and maybe get somewhere close for less than 1/2 price

I'm 99% sure the block is near enough an m20. Id hazard a guess that it will slot straight in using the e21 mounts.

What gear ratios does the m51 use?... You may find you'll need to do an electric speedo conversion..

Grab the engine from an e34... The sump will be the right way round.

Only issues I can see is the heating system for the glow plugs.. And then there's the torque. If your not careful you will have problems with snapping diffs and shafts. 280lbs is all the stock diff takes.

nas80 wrote:I'm 99% sure the block is near enough an m20. Id hazard a guess that it will slot straight in using the e21 mounts.

What gear ratios does the m51 use?... You may find you'll need to do an electric speedo conversion..

Grab the engine from an e34... The sump will be the right way round.

Only issues I can see is the heating system for the glow plugs.. And then there's the torque. If your not careful you will have problems with snapping diffs and shafts. 280lbs is all the stock diff takes.

ahh yes i forgot ive been advised to do a e30 rear end swap to make use of an electric speedo which is another Q i had haha

e34 it is!

if it used the e21 mounts that would be ideal!

You can use a kit car pulse generator on the prop for an electric speedo. perhaps butchering a speedo cluster out of an old 7/5 series?

The thing you need to watch out for is the turbo touching the standard brake assembly. I'm a big hater of what bmw did with the rhd e21 brakes.

You may find that flipping the turbo manifold upside down may work if it is in the way .. or even a custom effort if your desperate.

Good idea though.. If you get single headlights you got v.easy intercooler pipe routing.

nas80 wrote:You can use a kit car pulse generator on the prop for an electric speedo. perhaps butchering a speedo cluster out of an old 7/5 series?

The thing you need to watch out for is the turbo touching the standard brake assembly. I'm a big hater of what bmw did with the rhd e21 brakes.

You may find that flipping the turbo manifold upside down may work if it is in the way .. or even a custom effort if your desperate.

Good idea though.. If you get single headlights you got v.easy intercooler pipe routing.

i was thinking a custom speedo to save the hassle of the rear end swap, theres a fella local who put an s2000 engine in his e30 and went that way with the speedo

already have single headlights in

141hp and 200lb/ft that will go pretty well i reckon.

Do it!

Would love to see this done, would be very very cool imo.

My brother inlaw had an e39 525tds with the M51 when I lived in the UK.

The torque moved the car well enough, and cruising on the motorway we used to average 43mpg with stints at 85mph.

In the light e21 chassis they should be spirited enough and get up around 50mpg.

Anyway - here's some inspiration for you - a 190E with a new C Class 250CDi engine goes from 0 - 100 in 6.1 seconds, averages 48mpg!

http://carscoop.blogspot.com/2009/09/ba ... ofits.html

The engine will fit pretty much as a m5* but i think the engine angle is the same as the m20, if you car has an m20 at the moment you could try use the current box which would sort the speedo.

Take the engine from an e34 or even a opel omega (same engine), later engines will have more issues with ecu, currently try to swap a 1 series from a m47 to an n47 and looks we are going have to buy a complete car to swap the body looms