Electric headlamp conversion.
Posted: Fri Feb 13, 2015 4:40 pm
Although this topic has been covered many times in the past, when I mentioned the conversion in an unrelated thread, there was some interest in me posting details. Indeed I am always happy to read new posts on old subjects, something of interest often turns up. So here goes. Firstly I would like to acknowledge all previous posters on this subject, upon which my conversion was based. The only thing new, I believe, is the use of the headlight retractor unit to enable headlamp flashing. Flashing can be achieved by wiring a diode between the main and dipped beam feeds. This is an elegant solution used by MX5 owners without the flash facility. It does however place the total load of motor, main and dipped beam on the column stalk switch and feed which may or may not be detrimental. Also the stalk must be held long enough for the flash to take place above the bodywork. My solution required both the Mazda retractor unit and 3 relays (the 4th for dipped beam isn't strictly necessary ), which is a less than elegant! It will be interesting to possibly hear, from those more electrically competent than me, of a more elegant solution. Above all this was a fun project providing some geometrical and electrical challenges and works extremely well, so justifying the many hours spent on, in particular, the rarely used flash facility!
The car is a 1973 Plus 2 S130/5, so the mechanical conversion is to the failsafe, with balance bar, variant.
Both the motor and the retractor unit were from a Mazda MX5. I opted to mount the motor on the left side and utilise the existing balance bar lever. The motor arm is splined to the spindle so can easily be rotated to suit the mounted orientation of the motor.
The movement required to raise and lower the pods is governed by the relationship between the length of the arm on the motor and the length of the actuating lever on the balance bar. I opted to leave the motor arm as found and alter the actuating lever to suit since this is a straightforward cut n shut job.
This .pdf shows the relationship between the motor arm and the balance bar levers, also the calculations I did to determine the required length for the balance bar actuating lever.
The actuating lever was cut to size and welded leaving the existing pivot tube which was sleeved and threaded to accept a ball joint one side and a bolt on the other.
Next up fabricating a bracket.
The motor assembly must be mounted such that it's spindle is in line with an imaginary line drawn through the actuating lever pivot tube when in fully raised and fully lowered position. The motor arm must be moved to align with this imaginary line also.
A threaded stainless steel rod with a ball joint on each end provides the link. The length of this rod is determined by the distance from motor arm to balance bar lever and any adjustment on the rod is merely to achieve the correct length. The range of movement of the pod is solely determined by the length of the motor arm and the length of the lever on the balance bar. One of the heavier springs is used to damp vibration of the pod when the mechanism is in it's dwell angle.
The wiring diagram and description of operation is in this .pdf file.
I hope all this doesn't waffle on too much. All the original calculations and wiring diagrams were of course scribbled on some dirty scraps of paper and the time found to tidy it all up has only been found due to confinement following a ski accident! This will also impact on the planned May launch date .
The car is a 1973 Plus 2 S130/5, so the mechanical conversion is to the failsafe, with balance bar, variant.
Both the motor and the retractor unit were from a Mazda MX5. I opted to mount the motor on the left side and utilise the existing balance bar lever. The motor arm is splined to the spindle so can easily be rotated to suit the mounted orientation of the motor.
The movement required to raise and lower the pods is governed by the relationship between the length of the arm on the motor and the length of the actuating lever on the balance bar. I opted to leave the motor arm as found and alter the actuating lever to suit since this is a straightforward cut n shut job.
This .pdf shows the relationship between the motor arm and the balance bar levers, also the calculations I did to determine the required length for the balance bar actuating lever.
The actuating lever was cut to size and welded leaving the existing pivot tube which was sleeved and threaded to accept a ball joint one side and a bolt on the other.
Next up fabricating a bracket.
The motor assembly must be mounted such that it's spindle is in line with an imaginary line drawn through the actuating lever pivot tube when in fully raised and fully lowered position. The motor arm must be moved to align with this imaginary line also.
A threaded stainless steel rod with a ball joint on each end provides the link. The length of this rod is determined by the distance from motor arm to balance bar lever and any adjustment on the rod is merely to achieve the correct length. The range of movement of the pod is solely determined by the length of the motor arm and the length of the lever on the balance bar. One of the heavier springs is used to damp vibration of the pod when the mechanism is in it's dwell angle.
The wiring diagram and description of operation is in this .pdf file.
I hope all this doesn't waffle on too much. All the original calculations and wiring diagrams were of course scribbled on some dirty scraps of paper and the time found to tidy it all up has only been found due to confinement following a ski accident! This will also impact on the planned May launch date .