A hopefully comprehensive guide for M30b35 swapping a BMW e3
Hello, Mark. This is primarily for you. Site in Progress...
A hopefully comprehensive guide for M30b35 swapping a BMW e3
Hello, Mark. This is primarily for you. Site in Progress...
Engine Related Issues
This information may help with a M30b35 swap into other BMW platforms using the M30 engine. E12, maybe e28. I will address and provide as many photos as I can for each of the items I will list below
The reason I have selected to use a standalone engine management system (the www.classicdaily.net Turkey and Cheese) was to eliminate a few proprietary components that can be problematic or difficult to obtain. The Motronic DME can have issues with the circuit board after 30+ years of heat cycling. The Air Flow Meter (AFM) can be problematic and even rebuilt ones are expensive. The Throttle Position Sensor (TPS) is being replaced with an easier to find BMW M50 engine style. The Turkey and Cheese is compatible with the Motronic 1.3 55 pin engine harness and incorporates a wideband O2 sensor for better monitoring. I have also decided to use their coil over plug kit (using VAG R8 coil packs) to eliminate the distributor and central, single, ignition coil. With a lumpier camshaft, headers and a good fuel injection map, the b35 will produce significantly more power than the stock engine.
This project will also outline the retrofitting of a 5 speed Getrag Transmission. This has been more problematic than I anticipated.
COMPATIBILITY/ADAPTATION CONSIDERATIONS: ENGINE ONLY
Engine Mounts- later M30b35 blocks have different bolt boss locations. The exhaust side mount requires significant augmentation, The intake side probably does not but only 3 of 4 mounting holes line up so I did add a some material to the back of the mount to reduce potential flexing.
Throttle Actuation Assembly This was actually kind of fun to figure out but you will have to modify the pushrod set up for the carbs to work with the cable operated throttle body of the b35.
Cooling System I did not anticipate this being an issue but it is. Mostly due to the coolant hose routing.
Intake Modifications/AFM Delete
Accessories Do you want to use the 140a Alternator from the e34 (e32?) You will need to modify the mounting bracket from the donor engine if so, This was not straightforward but I will show what I did for this. Otherwise- you can use everything from your e3 and it will be easier.
Oil Pan/Oil Pump The oil Pan for the b35 will not work with the e3 subframe. The pan swap is easy- the oil pump took some figuring out.
Integrating Motronic 1.3 Wiring
Brake Booster The giant e3 brake booster will not allow for clearance for the b35 intake plenum (unless you cut/modify the plenum.)
Fuel System Additions A high pressure fuel pump and supply line will need to be installed.
Camshaft Choice This is especially important if you are going to go with a standalone engine management system. You will gain more power and torque with a more aggressive cam. I chose a 284 degree cam. The stock b35 cam is 264. Keeping the stock cam will make things a lot easier overall if you are fine with the stock setup.
Transmission/Drive line Issues
(If applicable)
My Bavaria was originally equipped with a Borg Warner automatic transmission.
I converted it to a 4 speed manual.
I was fortunate enough to acquire a 5 speed manual for very little money almost by accident. I am not sure installing a 5 speed is really worth the money otherwise. I thought it would only require a different driveshaft with a few other parts but,unfortunately, I was wrong.
Parts required for Getrag 265 5 speed installation:
-Bell Housing for m30 with internal plastic (or brass) pivot pin for clutch fork.
-Slave Cylinder- Good news- it's the cheap one. (note- if your manual transmission has the external mounted slave cylinder on driver side of the bell Housing- the OEM cylinder for the Bavaria is very expensive if you can even find one. The slave cylinder from a BMW 2002 tii is nearly the same size and much less expensive. Drill and tap the the outside for an m6 set screw. Then you can shim the approximately 2mm gap between the body of the cylinder and the mounting hole. Insert and tighten set screw to secure the slave cylinder. I have used this solution for about 13 years so far at the time of this writing.
test section-reference photo
Fuel System Additions
Adding the Fuel Injection Return Line
The carbureted E3 models used a mechanical fuel pump mounted to the
exhaust side of the cylinder head. These pumps are prone to premature diaphragm failure and will not provide the required 45psi of fuel pressure your new injection system requires. You will now also need a return fuel line for the fuel rail. I used the existing fuel line from the tank as the return line as it is not highly pressurized. I did run 8mm aluminum fuel to the rear of the vehicle for the high pressure supply line to the engine. I was hoping to avoid any rubber fuel line junctions in the line underneath the car. I was concerned this would be difficult as there are some hard turns in the line toward the back of the undercarriage, but, the soft aluminum tubing was easy to bend at gentle radiuses without kinking.The only rubber lines will be at the injector rail and the feed from the fuel tank. There may be better ways to route the new line but I followed the path of the old fuel line. I used sections of wire loom to cover the thing anywhere I used tie-wraps to secure it to the existing mounting points. This is to prevent two metallic tubes rubbing against one another and potentially wearing through. Make sure the 8mm rubber fuel line you choose is rated for fuel injection and use high quality hose clamps. (see photos) Also note- inspect the fuel rail for the injectors. There are two very short sections of rubber hose that have likely expired. One piece is straight and easy to change with properly rated hose. The other one, near the fuel pressure regulator is bent as the radius is tight. You will need to either order the special hose kit for BMW ($31 at FCP Euro as I write this of you can find a $10 8mm multi bend fuel hose (rated for 75psi) on Amazon and make your own replacement section.
High Pressure Fuel Pump Installation
This is in progress- images not loading
On the advice of a man who builds vintage racing BMWs I chose to use a genuine Bosch 044 high pressure fuel pump. The biggest advantage to using a universal type in line pump is if you have a roadside failure, a local auto parts store could likely carry this or a clone to get you back on the road. A BMW pump for a fuel injected classic model will at times be difficult to source and trying to find another model pump that can be made to be compatible is likely going to be a pain in the ass. Others may have a different opinion but if it's good enough for DB Couper, it's good enough to for me. I will get to how I installed it later but this section will address the electrical needs of this pump.
To start off you will need to run two separate stranded 12 gauge wires from under your dash to the rear of the trunk interior. These wires can run under the carpet and trim on the driver side. One wire should be a dedicated conductor for the pump only. I ran a wire directly from the battery to a fuse block and directly to the trunk. i will refer to this wire as the "hot" wire. The second wire need to run from a circuit either from the ECU or a ignition switched circuit. This will be a low current circuit used to trigger the fuel pump relay which I installed on a panel in the trunk.
The second component needed is an inertia fuel cut off switch. I suppose this isn't mandatory but if you are being responsible, it should be. In case of an accident, the impact will shift a weight in this switch which will in turn cut the voltage supply to the fuel pump. No need to have high pressure gasoline spraying about after a crash. I used one from a Ford mustang that I bought on eBay. These seem to be about $40 on Amazon.
The 3rd item you will need is a Bosch style 5 pin automotive relay. This will supply power to the fuel pump when the ignition switch is on. I installed a switch in my console to be able to turn the pump off if I need to troubleshoot something with the ignition on but car not running. Put this switch inline with your 12vdc trigger feed to the trunk if you want this option.
(upload additional photos)
Helpful Products/Resources
IN PROGRESS
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E34 X20 Chassis Receptacle
Classic Daily PnP Standalone ECU for BMW M30 -"Turkey and Cheese"
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Thanks to The Advisory Board
These are the people who helped me with advice to keep this project on track. Thank you all.
Clay Weiland
Arthur Krill
Jake Barkell
Mark Taylor
DB Couper
Alonzo Taylor
Marty Roach