MOC offers new back plates to suit SIBA contact breakers. These come complete with a new felt pad that should be lubricated with BOSCH grease, (available from Partsmart), to prolong the life of the Crankshaft cam and the contact breaker heel. BOSCH contacts have been unavailable as proprietary items for more than 20 years.

When setting the contact breakers, note that the time/position that the contact breakers open is the most critical part of the setting. The single lift cam has adequate time for re-charging the coil voltage at almost any gap setting. It is often not possible, (due to a worn cam), to set the gap to the correct specification together with the correct opening point. In this case, set gap as near as possible to the specification with the opening point at 4.5mm to 5.5mm before TDC. For the reverse timing, the gap is always a compromise, and adjusting the gap is the only way to achieve the correct opening point of 3mm to 4mm before TDC. The reason for this is that many cams are seriously worn from previous neglect of the felt pad and failure to use BOSCH grease. See articles in the Partsmart publication, “Karo-Tips”.

The following is a summary of the various contact breaker types, together with cost and fitting details:-

SIBA

Contact breakers originally fitted including a retaining clip for holding the coil wire as it passes through the clutch housing. Forward direction is marked ‘V’ (German – Vorn = forward). These are interchangeable with the reverse assembly marked ‘R’ (German – Rueckwarts=reverse). The R or V is upside down if the two types are transposed. This does not affect operation. The Black wire connects to ‘V’ on the right-hand set of contacts. The Red wire connects to ‘R’ on the left-hand set of contacts.

Part No. 279: Original Schier Kontakte part no:4681, Marked ‘V’ (forward) but may also be used in the reverse position. No longer available.

Replacement back plate for SIBA contact breakers, complete with new felt pad. Accepts original contacts above or the cheaper Villiers engine type listed below.

Part No 280: Siba backplate – Available from Partsmart

Bosch

Contact breakers originally fitted including a retaining clip for holding the coil wire as it passes through the clutch housing. Forward direction is marked ‘V’. These are not interchangeable between forward and reverse. Reverse direction is marked ‘R’. New BOSCH mounting plates are not available. If your contact breakers are worn out, you should convert to SIBA type with a new backplate.

Part No 278: Original Schier Kontakte part no:2162, Bosch part no: ZKT 72Z4Z forwards. No Longer available

Part No 281: Original Schier Kontakte part no: 2163, Bosch part no: ZKT 72Z5Z reverse. No Longer available

Alternative, – non original parts: SIBA

Contact breaker assembly as used in British Villiers engine. These are interchangeable with the reverse assembly. The forward assembly is fitted with a black cable and the reverse is fitted with a red cable. To fit these to a SACHS engine it is necessary to shorten the cable and connect to the appropriate wire using an insulated connector block, (not supplied). There is ample space within the contact breaker cover to fit the connectors. These contact breakers can be used with the above SIBA backplate, (Pt. No 280), to convert a BOSCH contact system to SIBA.

Part No 277: SIBA contact breaker assembly, (Villiers Type), state forward or reverse, available from MOC.

Ignition unit – inductive discharge – retains existing contact breakers

Worn contact breakers can be used almost indefinitely by using these systems as the contacts become a simple switch with no significant power flowing. See: Link to external site

Electronic Ignition Systems

There were 3 suppliers in Germany for electronic ignition systems for KR200; Steini-KTZ, Pukes, and a third one with programmable advance features. The systems are fully integrated into the existing contact breaker housing and an impulse rotor is attached to the crankshaft. The two existing wires and the engine ground are used as control and supply for the unit. Reversing system operates as before as the impulse sensor is timed exactly for the opposite direction of rotation. This is not a cheap solution but the spark is improved with more reliable running. A significant advantage is the easy replacement of the original contacts in case of failure on the road. For a compact unit that fits in the contact breaker housing check this website.

Siba dynastarts have a red oxide colour paint finish. Bosch units are finished in lime green paint. An extractor is needed to pull off the flywheel (Available from MOC Partsmart). You can identify the dynastart type by reference to the terminal tag numbers. (refer to Siba and Bosch black box systems and note the terminal numbers). The picture shows a Siba dynastart system fitted to all KR200 models up to chassis number 70643 ? reported date of introduction 6th April 1959.

Siba Units Fault: Pigtail routed around brush holder so that the cable is rubbing against the segment Insulation is worn through by friction on the rotating segment connecting wires ? when contact with the cable is made, the resulting short circuit damages both the armature and the stator.

Preventive action: As above, take care that the terminal is fastened to keep the cable close to the brush holder and without twisting.

Fault: Two of the brushes are connected to a terminal post between them and the pigtail can be too long or twisted, causing the cable to rub against the segment. Insulation is worn through by friction on the rotating segment connecting wires ? when contact with the cable is made, the resulting short circuit damages both the armature and the stator.

Preventive action: Ideally, the cable should be just long enough to reach the terminal post thus avoiding contact with the rotating segment connecting wires. If the cable is too long, it should be cut to length and a new terminal soldered or crimped on. Note the brush wire routing as shown in the above photograph.

Bosch units

Pigtail routed around brush holder so that the cable is rubbing against outside of central hub. Insulation is worn through by friction on hub ? when contact with the cable is made, a dead short occurs that often destroys the armature connections to the commutator.

Preventive action: Fasten the terminal so that the cable is held closely to the brush holder while allowing the brush to move freely as it wears. (see attached diagram). Take care not to create a twist in the cable that may increase the chance of it contacting the commutator segment connection wires. These are 1.5mm thick varnish insulated copper wires.

2. Pigtail routed around brush holder so that the cable is rubbing against the segment Insulation is worn through by friction on the rotating segment connecting wires ? when contact with the cable is made, the resulting short circuit damages both the armature and the stator.

Preventive action: As above, take care that the terminal is fastened to keep the cable close to the brush holder and without twisting. Refer to the drawing above for brush wiring arrangement on BOSCH units.

Note that the carbon brushes should be inspected frequently and certainly at each engine removal. If the brushes wear down to the connecting pigtails, and beyond, serious damage will occur to the commutator. In some cases, they can be restored by turning on a lathe but normally this can be done once only. In each case, the clearance must be restored between each commutator segment. If you do not understand any of the techniques involved, leave the servicing to a specialist. Dynastart components are hard to find on the used market and often extremely expensive. Look after yours and it will last the life of the car!

Service life of the brushes is dependant on the following factors:

1. number and duration of starting operations
2. Correct set-up of the carbon brushes
3. Condition of the commutator, excessive wear on brush operating area
4. Oil leaks from the main bearing seals. This can create short circuits from the carbon/oil paste that will burn out the unit
5. Run-out and excessive end float on the crankshaft
6. Total hours run of the engine
7. Worn main bearings

Life of the brushes can be extended by avoiding use of the reversing feature. The reason for this is that the small lateral movement in the brushes causes them to wear with a slight taper on the operating face. When reverse operation is selected, the contact area is reduced and excessive wear can occur. This effect can be reduced by minimising the lateral movement in brush holder. Squeezing the holder sides in reduces the play. Of course, the brush must be able to move freely within the holder.

How to identify Bosch & Siba systems

Late in 1958, soon after FMR took over from RSM, a number of changes were made to the engines including a different crankshaft and dynastart system. If you have a Messerschmitt with FMR badges and vehicle identification number plate, then it was normally built with a BOSCH system. All cars with FMR diamond badges and plates were built with BOSCH electrical equipment. The U.K. has more BOSCH units than other countries because Messerschmitts were sold in here in greater numbers than other countries from 1959. Many have since had replacement engines from earlier cars and thus require identification of the dynastart for service work and repair parts. It should be noted that each type will function equally well in a car equipped with Bosch or Siba control boxes. There are only minor differences in the Black Box internal circuitry and these do not affect operation. Almost all terminal connections are dual marked for both systems ? you do not need to mark the cables before disconnection as each has the identifying code stamped on the rear of the terminal. Take care when replacing any worn or damaged terminal flags ? these are ?handed? left and right to avoid contact with the adjacent terminal post on the terminal block.

Removing the dynastart flywheel.

Do not attempt this job without the necessary holding tool for the flywheel unless an air wrench is available. Never try to stop rotation by jamming the fan blades (many have been ruined this way). The correct procedure is:

1. Remove engine from the car and place on workbench. If you have a vice, clamp the front engine mounting plate in the vice jaws with the silencer taking the weight at the rear.
2.  Remove the fan cover and fan.
3. Place the holding tool in the locating holes and slot in the outer casing (as shown in the manual.
4. If you do not have the holding tool, you can fabricate an anti rotation device from a strip of metal locating on the fan retaining screw holes. CAUTION: take great care not to fit longer screws into the fan retaining holes. If a screw is forced in too far, some of the commutator segments will be pushed out and the dynastart armature will be damaged beyond repair!
5. One alternative is to use an air operated power wrench when it is not normally necessary to use a locking device at all. (These wrenches are used in car tyre shops to remove wheel nuts. They exert great torque with a hammer blow action and will loosen the most stubborn nut without rotating the crankshaft).
6. After dismantling, clean everything as described in the manual. Replace brushes as required. Carefully inspect the key. If the key is loose and there is evidence that the flywheel/ armature has been moving on the shaft, you will need a replacement crankshaft. Note that the out of balance condition created by this fault is a major cause of low engine power output.
7. Inspect the keyway on the dyanastart flywheel bore. If there is evidence of movement, the same caution as above applies. (see note below about replacement flywheel hubs).
8. If all is well, carefully re-assemble ensuring the key is properly in place. Fit the spring washer before the crankshaft nut and tighten. Failure to tighten this nut sufficiently is a major cause of the damage described above. If you have a torque wrench, you can set it to 110Nm (81 il/ft). Alternatively, use an air wrench providing you are sure it is capable of maximum torque.

How to identify BOSCH and SIBA dynastart systems:-

BOSCH – The flywheel, (technically this is the armature), is painted a light green colour. A 5mm wide key is machined into the crankshaft to locate the flywheel and prevent it rotating on the crankshaft. The bore is machined to a taper of 7.5:1 to match the BOSCH type crankshaft. The internal diameter is slightly smaller than the SIBA unit, preventing use with a SIBA stator.

BOSCH stator or field coil assembly: Almost identical to the SIBA system but can be identified by the terminal connection markings on the main power leads: 92r, 92l, D+, 30h, & 31, Earlier SIBA codes (shown below) are also included on each terminal allowing connection to BOSCH or SIBA black box system. Brushes are smaller than SIBA and have different terminal size and geometry. Can be used with a SIBA flywheel and will fit a SIBA engine. Theoretically, performance will be slightly reduced because of the small increase in the air gap between flywheel and stator. In practice, these performance differences will not be noticed.

SIBA flywheels are painted light brown colour similar to red oxide primer. A 3mm wide key is machined into the crankshaft to locate the flywheel and prevent it rotating on the crankshaft. This key is a special rounded type and must not be replaced with a standard key. (Note that MOC exchange SIBA crankshafts have a standard type key). The bore is machined to a taper of 10:1 to match the SIBA type crankshaft. The internal diameter is slightly larger than the BOSCH unit, allowing use with a BOSCH stator.

SIBA – stator or field coil assembly: Almost identical to the BOSCH system but can be identified by the terminal connection markings on the main power leads: A,B1,B2, HE, M. Brushes are larger than BOSCH and have different terminal size and geometry. One pair of brushes is connected to a 4mm terminal stud post and fastened with a nut. Cannot be used with a BOSCH flywheel because the external diameter is too great.

How to identify BOSCH and SIBA black box control systems:-

The black box control system can be used with either type of dynastart system. BOSCH systems can be identified by the black cover on the votage regulator. Many BOSCH systems are worn out now and the contacts are flimsy and prone to failure and most have been replaced with the SIBA product from Partsmart. It is possible to replace a BOSCH regulator with a SIBA unit but the back plate must be drilled to accept the different hole centres and some cables will need to be extended. It is often more cost effective to buy a complete new box from Partsmart particularly as all the cables, regulator, and ignition coil are new.

New Dynastart hub assembly. These can be available separately (price on application), or your existing dynastart can be fitted with a new hub. This is a time consuming job requiring specialised equipment as each re-built assembly must be dynamically balanced to the original armature. It is normally only worth doing if the armature is in good condition and free of deep grooves in the commutator face. Note that this repair service is done in Germany and can take up to six months to complete. Cost varies according to the work involved but is typically around 130UKP. If your need is urgent, you will need to buy a new one as listed below.

1574 SIBA flywheel  This is a complete new flywheel dynamically balanced and ready for use. Identified by light brown colour paint similar to red oxide primer and narrow keyway to suit SIBA crankshaft. Does not include stator or field coil assembly. Because of the heavy and fragile nature of this part, postage is extra at cost.

1575 BOSCH flywheel  This is a complete new flywheel dynamically balanced and ready for use. Identified by yellow colour paint, (we could not find a match for the light green), and 5mm keyway to suit BOSCH crankshaft. Does not include stator or field coil assembly. Because of the heavy and fragile nature of this part, postage is extra at cost.

Repair of the stator or field coil assembly is a specialised job. If you feel you have the necessary skills, excellent repair and fault finding instructions, with pictures, are included in 1807 engine manual 5.50UKP from Partsmart. Alternatively, take this manual, with your defective stator to an electric motor repair shop.

Other useful publications are:

1821 Dynastart leaflet Siba
1822 Bosch Dynastart manual

When the engine is stopped and the ignition switch turned on, the battery supplies power to all circuits.

1. START

Turning on the start switch energizes the start relay. Heavy duty contacts of this relay will supply high current to the stator coils, which are in series with the rotor by way of, HE of the reverse relay (which is de-energized as shown in the forward start position), B1, the rotor, B2 and ground. This is a series connected DC motor which has the characteristic of a very large amount of torque at low RPM’s.

After the engine starts and the ignition switch is released, the starter relay deenergizes. The stator coils are out of the circuit and from this point on the system operates like a DC generator. This DC generator supplies voltage and current to all electrical components in the car and charges the battery when the engine is running. The generator voltage must be controlled because a high generator voltage will result in a high generator output current. Too high of a generator voltage will cause light bulbs to burn out, fuses to blow, overheat the coil and overcharge the battery causing battery water to boil away. Generator output voltage is controlled by the voltage regulator relay.

2. GENERATOR

One side of the generator field coil is connected to the rotor through HE and B1 of the reverse relay. The B2 side of the rotor is grounded by the reverse relay as is the DF side of the generator coil through normally closed contacts of the regulator relay. This puts the generator field coils in parallel with the rotor creating a “shunt wound” generator that is driven by the engine. The output voltage of a shunt-wound generator is more constant than that of a series wound generator but will still increase as RPM’s increase.

3. REGULATOR OPERATION

The voltage regulator controls the generator voltage output by controlling the current in the “generator field coils”. Increasing field current generates a stronger magnetic field which results in a higher generator output voltage. Decreasing the current, produces a lower output voltage. The DF side of the generator fiels coil is grounded through the normally closed contacts of the voltage regulator relay.

When the engine starts and is running at low RPM, the regulator relay contacts are as shown on the diagram. As engine RPM’s increase, the generator output voltage will increase. This voltage is applied to the voltage cutout relay and the voltage regulator relay trying to energize both relays. (The voltage cutout relay would be more properly called the “charge circuit connecting relay). The voltage cutout relay will operate first when the generator output reaches 12.8 volts. Its contacts will connect the battery charging circuit (through the blue coils), to terminal 51/30 and the battery. The current flowing in these coils is the battery charging current.

Since generator voltage is greater than 12 volts, current will now be flowing into the battery and the battery will now be charging. (The charging current through the blue coil on the voltage cutout relay will add to the magnetic field to help keep this relay energized). When RPM’s increase and generator output reaches a voltage between 13 and 13.5 volts, the normally-closed contacts of the voltage regulator will open but will not fully transfer to terminal 61/D+. At this point, the ground is removed from the DF side of the generator field coil and a 6 ohm resistor is placed in series with it. This will reduce the generator output voltage by about 10%. This (normally closed) regulator contact will be opening and closing when the generator output varies between 13 and 15.5 volts to limit the charging current to the battery.

As engine speed increases, the generator output reaches 15.5 volts. Now the battery charging current becomes too high and excessive current could overheat the generator field coil and the voltage could possibly damage other electrical components. At 15.5 volts, the regulator relay contacts transfer completely across and connect DF to 61D+ and HE. This will “short out” the generator field coil and the generator output voltage will drop to zero volts. At this point, both the voltage cutout and voltage regulator relays will de-energize and disconnect the charging circuit. (blue coils). Now the whole procedure repeats giving us a charging current with over-charge protection.

When the generator output voltage is higher than the battery voltage, the charging current in the “blue coils” will try to keep both relays energized and current is flowing into the battery. If the generator voltage is less than battery, the current is reversed in these coils which will help to de-energize the relays and open the charging circuit when the cutout relay de-energizes. This insures that the battery is not supplying current to the generator field coil when the generator voltage is low. (This would happen when the generator output drops to 11 volts or 8 volts or even lower.)

4. LOW SPEED

With the engine running at low RPM’s, the generator produces a low voltage at “HE”. This low voltage is connected to one side of the Charge Lamp. The other side of the lamp is connected to the battery through the “Run Switch”. The charge lamp will be illuminated until the generator output voltage starts increasing and then the lamp will begin to dim. When the generator output voltage reaches 12 volts, there will be no voltage across the lamp and it will be completely extinguished. When the generator output reaches a maximum of approximately 15 volts, there will only be 3 volts across the lamp which is not enough to illuminate it.

5. MAINTENANCE

The only maintenance that could be performed is cleaning of the relay contacts. Contacts may be dirty or slightly pitted due to continual operation and sparking. DO NOT use a file, sandpaper or emery paper to clean the contacts. The bset way to clean them is to use a “contact burnishing tool” which may be found at an electrical supply store. This is an almost smooth metal blade that is inserted between the contacts and rubbed to polish them smooth. This will remove any dirt or small burrs on the contacts. If you can’t find a burnishing tool, you can use “crocus cloth”. This is an emery cloth impregnated with a material like “red jewelers rouge” that will clean and polish the contacts without scratching them.

6. ADJUSTMENTS

This is the easiest part of all. On the SIBA regulator there are no adjustments. However, if you want to make adjustments, you need a 12 VDC power supply that you can vary the output. With the regulator on the bench, apply +12 volts to terminal 61/D+ and the grounded case. When you increase the voltage to 13 or 13.5 volts the normall closed contact should open. It is possible to gently bend the normall closed contact so that the arm of the contact opens at this voltage. Further increasing the voltage to 15.5 volts should move the arm over to connect to the normally open contact. This contact can be bent to operate at this voltage. The cutout relay contacts should close at 12.8 volts.

7. AMMETER

For anyone wanting to install an Ammeter, all that is necessary is to disconnect the heavy copper wire from the top blue coil to terminal 51/30 and connect it to the Ammeter. This would mean adding an insulated terminal to the voltage regulator box. The ammeter would now measure current flowing into and out of the battery but not the starter current. I have installed an ammeter but the only units I could find was 0 to 30 amps. What I really wanted was a zero to plus and minus 10 amps. After many attempts to make a low resistance meter shunt (.000?? ohms) by paralleling small resistors I found an easy way. I took a length of heavy guage wire, formed it into a coil, and attached it across the ammeter terminals. I don’t know how accurate it is and don’t really care. It just shows me when the battery is charging and when it is discharging.

Any comments, suggestions or corrections would be appreciated.
Hajibaba@stny.rr.com

Late in 1958, soon after FMR took over from RSM, a number of changes were made to the engines including a different crankshaft and dynastart system. If you have a Messerschmitt with FMR badges and vehicle identification number plate, then it was normally built with a BOSCH system. All cars with FMR diamond badges and plates were built with BOSCH electrical equipment. The U.K. has more BOSCH units than other countries because Messerschmitts were sold in here in greater numbers than other countries from 1959. Many have since had replacement engines from earlier cars and thus require identification of the dynastart for service work and repair parts. It should be noted that each type will function equally well in a car equipped with Bosch or Siba control boxes. There are only minor differences in the Black Box internal circuitry and these do not affect operation. Almost all terminal connections are dual marked for both systems ? you do not need to mark the cables before disconnection as each has the identifying code stamped on the rear of the terminal. Take care when replacing any worn or damaged terminal flags ? these are ?handed? left and right to avoid contact with the adjacent terminal post on the terminal block.

Removing the dynastart flywheel.

Do not attempt this job without the necessary holding tool for the flywheel unless an air wrench is available. Never try to stop rotation by jamming the fan blades (many have been ruined this way). The correct procedure is:-
1. Remove engine from the car and place on workbench. If you have a vice, clamp the front engine mounting plate in the vice jaws with the silencer taking the weight at the rear.
2. Remove the fan cover and fan.
3. Place the holding tool in the locating holes and slot in the outer casing (as shown in the manual.
4. If you do not have the holding tool, you can fabricate an anti rotation device from a strip of metal locating on the fan retaining screw holes. CAUTION: take great care not to fit longer screws into the fan retaining holes. If a screw is forced in too far, some of the commutator segments will be pushed out and the dynastart armature will be damaged beyond repair!
5. One alternative is to use an air operated power wrench when it is not normally necessary to use a locking device at all. (These wrenches are used in car tyre shops to remove wheel nuts. They exert great torque with a hammer blow action and will loosen the most stubborn nut without rotating the crankshaft).
6. After dismantling, clean everything as described in the manual. Replace brushes as required. Carefully inspect the key. If the key is loose and there is evidence that the flywheel/ armature has been moving on the shaft, you will need a replacement crankshaft. Note that the out of balance condition created by this fault is a major cause of low engine power output.
7. Inspect the keyway on the dyanastart flywheel bore. If there is evidence of movement, the same caution as above applies. (see note below about replacement flywheel hubs).
8. If all is well, carefully re-assemble ensuring the key is properly in place. Fit the spring washer before the crankshaft nut and tighten. Failure to tighten this nut sufficiently is a major cause of the damage described above. If you have a torque wrench, you can set it to 110Nm (81 il/ft). Alternatively, use an air wrench providing you are sure it is capable of maximum torque.

How to identify BOSCH and SIBA dynastart systems:-

BOSCH – The flywheel, (technically this is the armature), is painted a light green colour. A 5mm wide key is machined into the crankshaft to locate the flywheel and prevent it rotating on the crankshaft. The bore is machined to a taper of 7.5:1 to match the BOSCH type crankshaft. The internal diameter is slightly smaller than the SIBA unit, preventing use with a SIBA stator.

BOSCH stator or field coil assembly: Almost identical to the SIBA system but can be identified by the terminal connection markings on the main power leads: 92r, 92l, D+, 30h, & 31, Earlier SIBA codes (shown below) are also included on each terminal allowing connection to BOSCH or SIBA black box system. Brushes are smaller than SIBA and have different terminal size and geometry. Can be used with a SIBA flywheel and will fit a SIBA engine. Theoretically, performance will be slightly reduced because of the small increase in the air gap between flywheel and stator. In practice, these performance differences will not be noticed.

SIBA flywheels are painted light brown colour similar to red oxide primer. A 3mm wide key is machined into the crankshaft to locate the flywheel and prevent it rotating on the crankshaft. This key is a special rounded type and must not be replaced with a standard key. (Note that MOC exchange SIBA crankshafts have a standard type key). The bore is machined to a taper of 10:1 to match the SIBA type crankshaft. The internal diameter is slightly larger than the BOSCH unit, allowing use with a BOSCH stator.

SIBA – stator or field coil assembly: Almost identical to the BOSCH system but can be identified by the terminal connection markings on the main power leads: A,B1,B2, HE, M. Brushes are larger than BOSCH and have different terminal size and geometry. One pair of brushes is connected to a 4mm terminal stud post and fastened with a nut. Cannot be used with a BOSCH flywheel because the external diameter is too great.

How to identify BOSCH and SIBA black box control systems:-

The black box control system can be used with either type of dynastart system. BOSCH systems can be identified by the black cover on the votage regulator. Many BOSCH systems are worn out now and the contacts are flimsy and prone to failure and most have been replaced with the SIBA product from Partsmart. It is possible to replace a BOSCH regulator with a SIBA unit but the back plate must be drilled to accept the different hole centres and some cables will need to be extended. It is often more cost effective to buy a complete new box from Partsmart particularly as all the cables, regulator, and ignition coil are new.

New Dynastart hub assembly. These can be available separately (price on application), or your existing dynastart can be fitted with a new hub. This is a time consuming job requiring specialised equipment as each re-built assembly must be dynamically balanced to the original armature. It is normally only worth doing if the armature is in good condition and free of deep grooves in the commutator face. Note that this repair service is done in Germany and can take up to six months to complete. Cost varies according to the work involved but is typically around 130UKP. If your need is urgent, you will need to buy a new one as listed below.

1574 SIBA flywheel 270UKP This is a complete new flywheel dynamically balanced and ready for use. Identified by light brown colour paint similar to red oxide primer and narrow keyway to suit SIBA crankshaft. Does not include stator or field coil assembly. Because of the heavy and fragile nature of this part, postage is extra at cost.

1575 BOSCH flywheel 270UKP This is a complete new flywheel dynamically balanced and ready for use. Identified by yellow colour paint, (we could not find a match for the light green), and 5mm keyway to suit BOSCH crankshaft. Does not include stator or field coil assembly. Because of the heavy and fragile nature of this part, postage is extra at cost.

Repair of the stator or field coil assembly is a specialised job. If you feel you have the necessary skills, excellent repair and fault finding instructions, with pictures, are included in 1807 engine manual 5.50UKP from Partsmart. Alternatively, take this manual, with your defective stator to an electric motor repair shop.

Other useful publications are:

1821 Dynastart leaflet Siba ?0.60
1822 Bosch Dynastart manual ?3.50

Each circuit is individually fused with separate fuses for each headlamp filament and two independent side light circuits. Thus, when a fault does occur, it is much easier to trace because a minimum of components is affected. Furthermore, if a fault occurs out on the road, there are still enough lighting circuits operational to allow you to continue your journey. The fuse box has eight separate circuits, the top two are for ignition switch controlled circuits such as the windscreen wiper and flashers. The remaining six are for main and dip beam headlamps, and left and right side lamps. All should be rated at eight amperes maximum, check yours now! Correctly sized new ones are available from Partsmart. All wiring assemblies are fully sheathed in PVC giving much greater mechanical protection than the taped wiring found in may modern cars. Each circuit is numerically coded according to German vehicle electrical standards and the same system is still in use in today?s German cars. Even the cable colours are similar and easily identified by those familiar with the standard. There is one major weakness in the design in that there is no protection for the main power and ignition coil circuits. If a short circuit occurs in the main red power cable (code number 30), the black ignition coil circuit (code number 15), or the feeds to the headlight dip switch, then the cable system will be severely damaged. When this happens the car will fill with grey smoke and may catch fire, only a quick disconnection of the battery will save it. Until recently, the batteries suitable for the Messerschmitt battery tray did not have sufficient power to create major damage and the internal resistance was often high enough to give time to disconnect the battery. January Kabinews detailed two separate incidents of short circuits, one of which caused injury to the owner from trying to disconnect the affected cables. Recent developments in battery design and the introduction of high-powered motorcycles with electric starters have led to the introduction of small high power batteries. Thus it is possible to fit a battery of 36 Ampere Hours into the same battery tray that would previously accommodate a battery of only 14 ampere hours.

Always fit the most powerful battery available to fit the battery tray. Gell cell batteries are particularly useful on a Messerschmitt. Starting current does not normally exceed eighty amperes and this is well within the battery capabilities. Originally intended as back up power supplies for emergency lights and alarm systems, they are completely sealed and can even operate inverted. These batteries must be re-charged at a low rate as there is only a limited provision to vent off the hydrogen gas produced during high charge and discharge rates. All have charging instructions and warnings on the case about over-charging. In normal use, the SIBA or Bosch dynastart does not provide enough power to overcharge the battery and output is regulated anyway by the current / voltage regulator. Dynastart output is barely adequate at the best of times and a quick calculation of the wattage of the various bulbs reveals that there is insufficient reserve power available from the maximum 135 watt charging output of the dynastart. Sachs and FMR put out dealer notices when the cars were in production warning that the battery required weekly re-charging if the car was used for short journeys in winter when the lights were in use. Many people believe that a larger battery will overload the dynastart charging circuit. In fact the reverse is true, a larger battery will be less loaded during the starting phase and will require less power to recharge. However, the high current available from these batteries will allow the Dynastart to be used for a long period before the battery is flat. Avoid using the starter continuously for more than twenty seconds and be sure to allow intervals of five minutes before operating the starter again. This will allow everything to cool down thus preserving the life of the Dynastart.

While there are many benefits of using a high capacity battery, one danger is the previously mentioned unprotected circuits and the additional capacity can allow sufficient current to pass to cause a fire. One way to avoid this is to place a fuse in the main red power cable at the rear bulkhead terminal strip. Partsmart now offers an in line fuse of 30 amps rating to protect this circuit. Simply disconnect the large red wire from the terminal strip located at the rear bulkhead, insert one wire of the fuse-holder into the vacant terminal and re-connect the red wire into the terminal provided with the fuse holder. One spare 30amp fuse is provided with the holder and the standard replacements can be obtained throughout the world.