Speed prop speed sensor

[willturner]

Please can somone advise me where I might obtain a speedometer drive sensor. Mine is broken.
The instruments all have white backgrounds and "Marlin" logos. There is a marlin fish logo on speedo and tacho.

[terryrscott]

Re: Speed prop speed sensor

i had the same problem and got mine from car builder solutions, thats if you just want the adadpter that fits onto a short speedo cable that comes out of the gearbox., if you need more info, get back to me.

[A_Hogg]

Re: Speed prop speed sensor

Maybe try Caerbont . I take it that you have an electronic speedo not mechanical? What do you mean by broken as I've found that the sensor positioning is quite critical in order to get a reading at the speedo face.

[terryrscott]

Re: Speed prop speed sensor

sorry maybe i assumed to much
on my cabrio i have an electronic speedo with a mechanical drive (speedo cable) from the gearbox about 6 inches long which fits onto car builder solutions item on this link https://www.carbuilder.com/uk/digita...gnal-adapter-2
i then wired that to the speedo, and it works

[milliemarlin]

Re: Speed prop speed sensor

I think you need to determine what type of sensor you have at the moment. One of the joys of hand built vehicles is that each builder finds a different way to solve a problem.

I am pretty sure the instruments you have need a electrical pulse to gauge the speed. Most donor vehicles have a mechanical cable drive from the gearbox to the speedo. So the speedo drive has to be set up in another way to the donor.

A couple of ways of implementing a speedo sensor that I know of are:

1. As mentioned convert the mechanical output from the gearbox to an electrical signal. A number of companies have such convertors. Check to see if there are wires near the gearbox speedo output. If you know the type of gearbox you have I may be able to be more specific.

2. When I built my car such senders were very expensive so I took a more diy approach. I bonded four small magnets to the prop shaft near the diff. I then made a bracket to mount a sensor to detect the magnets as the car is driven. I started with a steel bracket but that interfered with the magnets. So I remade it in alloy. This had a disadvantage that after a year or so the bends relaxed and the sensor ended up too far away to detect the magnets reliably. Fortunately it is an easy job to adjust the sender and after a number of years it seems to be stable. This is probably the best case scenario for you - a simple adjustment to fix the problem.

Good luck with the hunt. If you have problems let us have a bit more information if possible.

Better still share your success story.
Paul

[willturner]

Re: Speed prop speed sensor

Thank you for the responses. I should have mentioned thet this is an electronic speedo, I can see it is part of a matched set, maybe bought from Marlin, maybe sourced from Caerbont. I will go through a careful set-up calibration, before declaring the sensor U/S. I see demon tweeks sell revotek sensors at £55.00. This will make me very careful to declare the sensor dead before purchasing, especially as there seem to be a lot of sensors (usually motorbike) at £5;00 to 10:00...........

[chris_cussen]

Re: Speed prop speed sensor

Same solution as Paul using an ETB speedo which can be programmed to show the correct speed by setting the number of counts per mile.

[kieran78]

Re: Speed prop speed sensor

I have smiths cobra speedo (digital) and have connected up one of these https://www.force4.co.uk/item/veethr...iver-Cable/T55

Unfortunately, my 'cobra' speedo is 1st generation (-A on part code) and over 21-years old. Despite incredible service from technical, it appears to be incompatible with gps, the current generation (-B) is OK. I suspect a correctly chosen resistor would smooth the signal out, but it is beyond my skill.

Therefore, hall sensor ordered from ebay.