Speedo on my Acewell has a tendancy to stop working occasionally. As if the magnets come off if you like but then it fires up again.

It happens when going fast as in at the track day went off on the straight going flat out then comes on again slowing down round the bend.

Its a magnet and reed switch setup, is the switch getting confused and tripping up due to the high trigger rate?

Will the Acewell be more reliable with the Ford sensor attached to the type 9 output??

Ta,
Steve

I've never had any problems with mine using the standard Acewell sensor [except when I forgot to tighten the bracket holding the sensor].

Not done a track day yet though.

Stu

Sounds as tho' something is moving when under extremes of power etc. possible the prop may be moving fore & aft a bit if engine/gearbox/diff mounts have a bit of movement? The reed switch works best with the magnet lined up with one of the lines across the end of the switch
You could only use the Ford sensor if it has a square wave output (like Hall sensor/reed switch) I believe.

How many magnets are you using and where are they located?

At a high enough frequency the switch cannot react quick enough and it ends up staying closed. At this point the output would drop to 0 pulses resulting in 0mph.

If the magnets are on the prop, you could try locating them on the drive shaft to reduce the frequency, or use less magnets and re-calibrate.

Or as said before it may be that something is moving that is causing a loss of magnetic field by the switch.

Cheers

Ian

There's just one magnet on the forward UJ of the prop. The sensor is on a bracket bolted to the gear box case.

Can't really see it moving much but as said drops to 0mph.

I have one magnet on the prop just behind the UJ and it seems OK.

What speed is it going off at? Mine has only been up to just under 100MPH [on a private road obviously] and was fine.

Stu

Its around 70~80mph but isn't all the time. I've just had a thought... need to take the tunnel off and make sure the gap is correct after my crash as it didn't do it before that

Steve