Engine
E32/E34 vs E28etc
Basically, you want the engine out of an E32 / E34. It's newer, better (bigger valves), & easier to fit than that out of an E28 (due to a coolant elbow on the back of the E28 head, & the need for the E32/E24 sump & oil pump with either engine). I had the option of a free E28 engine, but turned it down because of the above! There are parts of an E28 that are well worth having though - see below.
Mounts
.de mounts are the most commonly used, copies are also available. Roughly £150, & let you bolt the engine straight in. You can use standard M20 rubber mounts (others?). There are 2 positions on the .de mounts - I'd recommend using those that place the engine furthest back (AKA 'position 3'). You may have clearance issues with the bulkhead - I didn't, but other people have solved them with judicious application of a lump hammer... If you use the furthest forward position, you'll have virtually no room for a radiator, as well as worse weight distribution.
Some people have also had issues with clearance to the brake servo - again I didn't, there's usually nothing a dab with a grinder on the inlet manifold can't solve. Failing that, a mk1 golf GTI servo is a straight swap (It is smaller in diameter but slightly thicker, makes the pedal a little harder as it's capacity is slightly lower but it has no effect on the car's overall braking force).
WRT actually putting the engine in the car - I'd do it with the gearbox attached, as bolting the two together under the car would be challenging to say the least (changing the clutch will also be a horrible job under the car - buy a new one now!) It's easily doable this way round, providing your engine crane goes high enough.
Alternatively (if you really want to be able to remove the gearbox on its own), you can bash the transmission tunnel floor up where it meets the bulkhead and chop the top bellhousing bolt lug off of the gearbox.
Gearbox
(anyone used an auto?)
(any issues with the E34 box differing from E28?)
E34/E28 manual box. M20 boxes won't bolt up to an M30, but some M10 boxes will.
You'll need the clutch to match the gearbox, & a flywheel to suit. Easiest way is to get it all out of one car! But if you've got a auto donor, don't forget you'll need a spigot bearing for the end of the crank too. E28 M535i flywheels are lighter than E34 ones, so go for one of these if you can! You'll want the clutch to match (the E34 cluch won't work with an E28 fly for example) - I'd certainly recommend a new clutch while it's out & easy to change...
The M30 'box bolts to the shell using standard E30 gearbox box mounts. The 325i gear linkage is needed (320i is no good), to make the gear lever stick up in the right place...
M20others? clutch slave cylinder can be used.
Prop
You've got a few choices here - none being the obvious 'best'
1: E30 M3 prop. This has the correct flange to bolt to the E30 diff & M30 box. Depending on your engine position though, it may well not be short enough to fit. It's an expensive option if you then need to get it shortened. You can make it a little bit shorter by removing the lock nut from the middle - don't forget to align the 2 halves (white dot on each) when you put them back together though.
2: E36 328i prop with reversed centre bearing
3: Custom - companies like reco-prop (www.reco-prop.com) can shorten / fabricate a prop for you. I had one made using an E28M535i front half, & E30 rear half. This was slightly too long for me to use as standard (the 2 halfs mate ok though), so reco-prop shortened the front half, fitted a new centre bearing & balanced & painted it for me. That cost £150 ish.
4: Gearbox flange swap - you can swap the flange on the back of an M30 box to enable using a standard E30 prop. The M30 uses a bigger flange (& coupling) for a reason though...
5: M10 box/prop
Diff
You can use any E30 diff. E28 / E32 items would require extensive mods to fit.
Small case diffs don't last long though (ask Gareth), & anything shorter (higher number) than a 3.64 will probably be too short to ideally suit the M30. 3.64 is close to ideal on a standard engine, with 3.46 etc more suited to those with more power...
Wiring
Using the M30 engine loom, some minor modifications are needed... Temp sensor - the brown temperature sensor on the M30 block will need swapping for an E30 (M20 only?) item.
Extend coil connection - you'll probably find the coil will need to move, & the 2 (non-HT) connections to it will need extending. Not a difficult job, & best left until you know exactly where you'll mount it & how long they need to be.
Facelift wiring mods (these apply to those with a facelift shell) - the engine will run without doing them, but for everything to function correctly, the following are needed;
To get the 'economy swingometer thingy' working you need to swap pins in the M30 loom:
Pin 3 (black and white) and pin 8 (black and purple).
To get the electric windows and sunroof to work with the doors shut and for the heater blower to work at all you need to connect the black and green wire from pin 15 on the E30 C101 to a small spade connector on the starter motor.
rev counter?
Prefacelift mods (these apply to those with a pre-facelift shell);details
C104/C101 rev-counter & econometer mods
Starter cable - If you're using an E32 engine, you'll need the +'ve cable to the starter motor from your E30, as the E32 power terminals are on the other side of the engine bay (& much nearer the starter motor). E34?
Power distribution block - there is a power distribution block on the E32 (E34?) loom, near the ECU, that needs a direct live feed to it.
Using the M20 engine loom...
ECU
The standard E32 / E34 ECU should be used. The M30 loom will allow it to be fitted under the dash, but getting all of the connectors through the bulkhead is a PITA! The loom is also slightly short - you may have to rotate the ECU to allow it to bolt in place.
Plumbing
You'll need an E32/E34 top hose, with the built-in T-piece to the heater matrix. This T-piece goes to the bottom connecton on your heater matrix.
You need another T-piece to go in the pipe from the thermostat housing to the header tank (from an E28; BMW part number # 11 53 1 272 866). You can then connect from here to the top connection on your heater matrix.
Header tank
If you've got a pre-facelift shell, you'll need to move your header tank - the stock location is in the way of the air intake. A facelift m20 header tank sits nicely on the nearside wing - you'll need to extend the level sensor wiring round to it. It can obviously stay where it is if you're starting with a facelift m20 shell!
Radiator
You can use a standard E30 radiator - a new 325i rad will probably do the job. An M30 is a big engine in a small E30 engine bay though, & heat is an issue, so a bigger radiator is preferable.
An E28 m535i radiator can be had from GSF for £150ish (IIRC), is loads bigger than an E30 rad and fits perfectly. There are even unused holes in the shell that you can bolt it up to - anyone would think BMW intended it to go there...
An E34 radiator can also be used, but it's significantly thicker than the E28 item, so you may have clearance issues to the front of the engine. To mount the E34 radiator you can use the standard 325 bottom plastic 'cup' mount on the right hand side and another right hand side one on the left hand side, riveted to the body as it doesn't clip in quite perfectly. The radiator sits in this like it was made to measure!
You'll need to make some kind of mount for the bottom of the radiator. I made a simple mounting bar that bolts onto the standard mounting points, and locates on the bottom of the E28 radiator, so no modifications were needed to the shell or rad.
The crankshaft pulley will be very close to the radiator whichever you use. Unless you're keeping the M30 aircon setup (& I very much doubt you are!), you can chop the air conditioning belt drive part of the pulley off, simply by running an angle grinder down the middle of the 'V', it removes the spot welds and the two halves fall away.
Fan
You will never fit an M30 in an E30 engine bay with the viscous fan on the front! Electric is the way forward. You'll have to get creative with how you mount it, but plenty of cable ties & simple brackets should sort you out. Mount it in front of the rad obviously, & make sure you wire it up the right way round!
You can get an electric fan from pretty much any car. I don't even remember where mine came from! An E32 or E34 aircon fan is nice & big & powerful though...
An E28 m535i radiator has temperature switches fitted to it, that you can use for your fan. Alternatively, you'll need to fit a temp switch somewhere, or a manual switch inside the car (you can have both!).
To do a 'nice' fan install, you can add a relay & fuse to the fusebox. insert details
Airbox
The E32/E34 airbox fits just fine in the E30 bay. It's got a built in heat shield too - a distinct bonus as it sits above the exhaust manifold... Aftermarket options are out there, but I can't see an advantage other than space. M20 cone filters etc will be too small incedentally.
To fit the standard airbox you will need to move the washer bottle. An alternative bottle can be fitted to the E30 airbox mount (corsa bottles apparently fit!), or the standard location - an E34 non-intensive bottle is a nice fit here. Alternatively, find something in the scrap yard that looks right! 324td washer bottle (p/n 6166 1385 280) is ideal.
Unless you find a suitable dual washer bottle, you'll need to modify / remove the associated intensive/headlamp washer electronics.
Throttle cable
The M20 throttle cable is too short - use one from an E32/E34 - about £15 brand new from BMW or off your donor. My M20 throttle cable was pretty ropey when I inspected it; a new one might not be a bad idea.
Exhaust
The issue here is clearance to the steering coupling.
An E28 manifold is apparently a nightmare in this respect, & the E32 item I had (with a flexible coupling in the front section) would also have needed lots of work. The E34 item benefits from the removal of excess material from the flange (insert pic), & bending the lip on the coupling heat-shield (it's easy to see what catches!) but is a comparatively easy fit. Further work will be needed to enable the fitting of an E36 steering rack.
E32 / E34 downpipes can be used, usually cut off before the front box.
Some custom work will be needed to get from here to the back of the car! Options include attaching a flange to the downpipes to connect to an M3 exhaust system (details), getting handy with a welder, or taking the car to a custom exhaust shop.
Fuel connections - the return to the tank comes from the FPR. The pipes should just go straight on...
PAS - use the M30 pump; the E30 M20 pipes will bolt straight to it (pipes from a 4cyl E30 are too short).
Cruise control - if you have it, it'll connect straight to the M30 throttle linkage with no issues.
Brake servo connection - you may need a new vacuum pipe to go from the M30 inlet manifold to the E30 brake servo.
Maintenance / prep - before fitting the engine it's well worth doing the sump gasket, as that'd be a serious PITA in the car, but easy on the stand. Water pump, Oil/filter, Coolant, PAS fluid, Spark Plugs, PAS/altenator belts, dizzy cap/rotor arm - these will all want changing too & I'm sure you can work out which need to be done before the engines in & which need to wait!
