Topics:
- BMW engine
- Initial project tasks
- Oil pump inspection
- Distributor removal
- Starting and charging system
- Frame with displays and computer
- Dashboard with electrical installation
- Cooling
- Fuel tank
- Intake pipe, air filter, crankcase ventilation hoses
BMW engine
The decision to use this BMW engine for the conversion project was made quickly; it was too defective for students to work on, but still good enough to refurbish. The engine is from a BMW 5-series E34. The table below shows the engine’s specifications.
Initial project tasks:
As previously mentioned, the BMW engine is in good condition. A highly motivated student immediately started removing auxiliary parts. The wiring harness, original ECU, and the ODB1 diagnostic connector are definitively removed. Other parts such as the valve cover, manifolds including exhaust, frame with radiator are checked, cleaned, and later reassembled with new gaskets, O-rings, and hose clamps. The valves are adjusted, and the coolant pump is preventively replaced due to age and rust.
Of course, the oil is changed and the cooling system cleaned. At a later stage, when the engine has run for at least an hour, the fluids are replaced again and the filters renewed.
The photos below show the beginning of the project where the auxiliary parts are disassembled and the valve clearance adjusted. Click on the photos for full size.
Oil pump inspection:
While cranking the engine, attention was paid to the oil circulation in the cylinder head. During starting, there was no oil supply visible to the camshaft etc. It was unclear whether the oil pump and pick-up screen were functioning correctly; after all, the engine had been used for practical assignments in the past. Something might have been lacking in the oil supply. Therefore, it was decided to remove the oil pan and inspect the oil pump and screen.
After disassembly and inspection, we concluded that the oil pump and its components were in order. The parts were reassembled and the oil refilled.
Removing the distributor:
The ignition system will be equipped with a DIS coil. We remove the original coil and distributor. Removing the distributor left an uncovered hole in the cylinder head. Here, the end of the camshaft and the camshaft seal are visible. At a later stage, a camshaft position sensor can be installed here in combination with a MegaSquirt III (for now we’re using the MS-II). To neatly cover the opening, a cover plate was designed using AutoCAD and created with a 3D printer. The photo was taken 10 minutes after the start of printing. In total, printing took 3.5 hours.
Starting and charging system:
One of the visible defects was a faulty starter relay. At least, the stud terminal was broken. Repairing the starter relay seemed impossible. Fortunately, the costs were manageable: for 9,- the local revision specialist provided a new starter relay. The image shows the defective one (left) and the new one (right).
We had less luck with the alternator. After connecting the positive wires, a short circuit was discovered when connecting the ground wire. After a brief search, the cause was found: the B+ terminal of the alternator was in contact with the casing. The resistance between the B+ and the housing was 0.2 ohms. The alternator was immediately disassembled and opened. What was found? The D+ terminal was contacting the casing because the internal components were not seated straight in the housing, and the plastic bush was broken. The alternator could never function this way; presumably, a student disassembled and incorrectly reassembled the alternator years ago when the engine was no longer running.
After repairing the starter motor and alternator, the wiring was started. The red wires are visible in the image below.
The positive wire from the battery is connected to the B+ terminal of the alternator. Additionally, the positive wire to the starter motor is mounted on the same stud.a0
The D+ wire on the alternator is connected via the charge indicator lamp on the dashboard to a fuse (terminal 15). The control wire from the starter motor (terminal 50) is operated by the start button on the dashboard.
Frame with displays and computer:
A desktop computer with two displays is mounted on the engine frame. These displays will eventually show the dashboard meters and ignition maps. It is also possible to demonstrate measurements with an oscilloscope (Picoscope) on a screen.
The frame is modified so that the two screens can be mounted one below the other. The screens are tilted at a certain angle for clear visibility when standing in front of the engine.
The desktop computer is placed behind the displays on the engine frame. The PC is a Dell brand Optiplex XE (Core2Duo 2.6 GHz, 4 GB RAM). This type of computer is designed to run 24/7 under heavy industrial applications in warm, dusty environments. This PC is therefore extremely suitable for functioning on the engine frame as the engine runs. The standard hard drive is replaced by an SSD to minimize the risk from vibrations. The PC and displays are sponsored by Zenid.net.a0
Dashboard with electrical installation:
A panel with several components is installed below the displays. The image shows the back of the panel with the wiring.
From left to right:
- Ground disconnect switch
- Ignition switch (terminal 15) and start button (terminal 50)
- Cooling fan switch
- Lamp terminal 15
- Charge indicator lamp D+
- Fuse box 1 (6x)
- Fuse box 2 (6x)
The wiring diagram was recently modified. The new version will be added to this page soon.
Cooling:
The original cooling system components were incomplete, dirty, and/or defective. In addition to a new coolant pump replaced preventively, the following components are newly installed:
- Radiator;
- Coolant reservoir;
- Six new radiator hoses;
- Cooling fan.
These components are not from an E34 but an E46 (3-series). The size of the radiator, the diameter of the coolant hoses, and the capacity of the cooling fan are sufficient to ensure proper cooling. The cooling fan has a capacity of no less than 390 W.
The images above show the radiator and the expansion reservoir. These components belong together; the reservoir can be attached to the top and bottom of the radiator. A special frame is required between them. This frame is not depicted.
The image below shows the cooling fan. The fan is also part of the radiator and the reservoir; these three components are mounted together. The image below also shows the moment the cooling components, consisting of the described items, were hung in the frame. In this way, the height and distance between the thermostat housing and the reservoir pipe could be adjusted. Ultimately, an S-shaped cooling hose is used here.
The radiator is mounted as follows:
- Rubber blocks are placed between the radiator and the horizontal bar of the motor frame for support;
- The radiator is clamped in all directions by the metal rods on the left and right;
- The metal rods on the top prevent the radiator from tilting.
The flange on the top of the radiator is normally equipped with a coolant hose of original dimensions. The bends in the hose do not match the space available for this engine. Therefore, the standard coolant hose was removed from the flange, and the ring that had shrunk around it was ground off. In its place, two hoses with a diameter of 38 mm (G4278-17033) were cut to size and mounted in an S-bend.
There was some searching for a suitable junction for the two hoses. Plastic PVC pipe proved too soft and deformed with warm coolant, so it was unsuitable. The auto parts store eventually found a brass hose connector (WK 34305) that fit perfectly. The ribs on the exterior securely clamp the hoses in place.
The image below shows the brass hose connector halfway inserted into one coolant hose. The other coolant hose is also mounted on the connector, and the hose clamps are tightened firmly.
The same type of hose connector is also mounted between two other coolant hoses at the bottom of the radiator.
Fuel tank:
The fuel tank with a capacity of 20 liters was already in the same position in the old setup. The tank is attached to the engine frame and is located in the corner, next to the battery, underneath the lower radiator hose. An original chrome cap seals the tank.
The image below shows the fuel tank and the two fuel hoses. One is the supply and the other the return. The hoses run to the fuel rail, where the injectors are mounted. These components are described in the “actuators” section.
Intake pipe, air filter, crankcase ventilation hoses:
The original intake pipe, crankcase ventilation hoses, PWM idle air control valve, and air filter housing were missing. Even if some parts had been present, it was likely due to aging and frequent disassembly/assembly that cracks would have formed. These parts, except for the PWM control valve, have been newly purchased. The intake pipe and crankcase ventilation hoses were ordered from a BMW dealer. The original air filter housing would not fit neatly on the engine frame, so the choice to install an open air filter was quickly made. The air filter (K&N, KNRC-3250) had the same diameter as the intake pipe.
Using AutoCAD and a 3D printer, an adapter was designed and printed to fit between the air filter and the intake pipe.
